Re: [R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Rolando Valdez]

into 0,1, which you could do with lapply() instead of
> using
> >> inverse durations.
> >>
> >> Hope this helps,
> >>
> >> Roger
> >>
> >>> El vie., 21 de jun. de 2019 a la(s) 02:53, Andres Diaz Loaiza (
> >>> madi...@gmail.com) escribió:
> >>>
> >>>> Dear Rolando,
> >>>>
> >>>> The advantage of using Open Street Maps engine is that you can give
> the
> >>>> travel option. This means you can select whether are you traveling by
> >> bike,
> >>>> car or walking. The previous approach didn't consider this topic. For
> >> this,
> >>>> you should have added a vector layer depending on your position of the
> >>>> street you can take (or not). Open Street Maps project allow you two
> >>>> options: a service in which you give your current position, the
> position
> >>>> you want to reach and your transport method (giving you back the
> fastest
> >>>> route). Or the option to download the engine/algorithm compile by
> >> yourself
> >>>> (if I am not wrong is made in C or python) and then you can make your
> >> own
> >>>> calculation at your own computer. For the first option, the package
> >> OSRM is
> >>>> an interface in which send a request to the OSM web page and wait for
> an
> >>>> answer. With this method, you can send a couple of request at the same
> >> time
> >>>> but no to many (you should read the manual for this). Of course, also
> >> will
> >>>> depend on whether the OSM server is down or not (or busy).
> >>>>
> >>>> I have to say that I used some years ago this app and nowadays I know
> >> that
> >>>> for some cities OSM has more streets reported than the same google
> maps.
> >>>> Also is an open project and they let you download their data for free,
> >>>> contrary to what google maps do.
> >>>>
> >>>> All the best,
> >>>>
> >>>>
> >>>> Andres
> >>>>
> >>>> El vie., 21 jun. 2019 a las 4:30, Adrian Baddeley (<
> >>>> adrian.badde...@curtin.edu.au>) escribió:
> >>>>
> >>>>> Rather than converting an object of class 'SpatialLines' or
> >>>>> 'SpatialLinesDataFrame' to the spatstat class 'psp' and then
> >> converting it
> >>>>> to the spatstat class 'linnet', it is safer and more efficient to
> >> convert
> >>>>> the SpatialLines* object directly to class linnet using
> >>>>> as.linnet.SpatialLinesDataFrame() from the package 'maptools'.
> >>>>>
> >>>>>
> >>>>> Prof Adrian Baddeley DSc FAA
> >>>>>
> >>>>> John Curtin Distinguished Professor
> >>>>>
> >>>>> Department of Mathematics and Statistics
> >>>>>
> >>>>> Curtin University, Perth, Western Australia
> >>>>>
> >>>>>
> >>>>> 
> >>>>> From: Rolf Turner 
> >>>>> Sent: Friday, 21 June 2019 10:08 AM
> >>>>> To: Rolando Valdez
> >>>>> Cc: r-sig-geo@r-project.org; Adrian Baddeley; Ege Rubak
> >>>>> Subject: Re: [FORGED] [R-sig-Geo] Create a Spatial Weight Matrix
> based
> >> on
> >>>>> road distance
> >>>>>
> >>>>>
> >>>>> On 21/06/19 12:26 PM, Rolando Valdez wrote:
> >>>>>
> >>>>>> Dear community,
> >>>>>>
> >>>>>> Is there any way to create a spatial weight matrix based on road
> >>>>> distance?
> >>>>>> I am trying to use the road distance between two points instead of
> >>>>>> euclidean distance.
> >>>>>>
> >>>>>> I've seen that there is a package named osrm. Can anyone give some
> >>>>> advice?
> >>>>>
> >>>>> I don't know anything about "osrm".  Calculating "road distances" can
> >> be
> >>>>> done in the spatstat package reasonably easily, if you take the
> trouble
> >>>>> to represent your collection of roads as a "linnet" object.
> >>>>>
> >>>>> Given that you have done so, suppose that your linnet object is "L"
> and
> >>>>> that you have vectors "x" and "y" specifying the points on L (i.e. on
> >>>>> your roads) between which you want to know the distances.
> >>>>>
> >>>>> Do:
> >>>>>
> >>>>>   X<- lpp(data.frame(x=x,y=y),L)
> >>>>>   dMat <- pairdist(X)
> >>>>>
> >>>>> The object "dMat" is a (symmetric) square matrix; dMat[i,j] is the
> >>>>> distance between point i and point j.  (Of course the diagonal
> entries
> >>>>> are all 0.)
> >>>>>
> >>>>> If your collection of roads is specified by means of a shapefile,
> >>>>> vignette("shapefiles") will tell you how to turn this collection
> into a
> >>>>> "psp" ("planar segment pattern") object; the function (method)
> >>>>> as.linnet.psp() can then be used to turn the "psp" object into a
> >>>>> "linnet" object.
> >>>>>
> >>>>> HTH
> >>>>>
> >>>>> cheers,
> >>>>>
> >>>>> Rolf Turner
> >>>>>
> >>>>> --
> >>>>> Honorary Research Fellow
> >>>>> Department of Statistics
> >>>>> University of Auckland
> >>>>> Phone: +64-9-373-7599 ext. 88276
> >>>>>
> >>>>>  [[alternative HTML version deleted]]
> >>>>>
> >>>>> ___
> >>>>> R-sig-Geo mailing list
> >>>>> R-sig-Geo@r-project.org
> >>>>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
> >>>>>
> >>>>
> >>>> --
> >>>> Andrés D.
> >>>>
> >>>
> >>>
> >> --
> >> Roger Bivand
> >> Department of Economics, Norwegian School of Economics,
> >> Helleveien 30, N-5045 Bergen, Norway.
> >> voice: +47 55 95 93 55; e-mail: roger.biv...@nhh.no
> >> https://orcid.org/-0003-2392-6140
> >> https://scholar.google.no/citations?user=AWeghB0J=en
> >
> >
> --
> ___
> Danlin Yu, Ph.D.
> Professor of GIS and Urban Geography
> Department of Earth & Environmental Studies
> Montclair State University
> Montclair, NJ, 07043
> Tel: 973-655-4313
> Fax: 973-655-4072
> Office: CELS 314
> Email: y...@mail.montclair.edu
> webpage: csam.montclair.edu/~yu
>
> --
Rol~

[[alternative HTML version deleted]]

___
R-sig-Geo mailing list
R-sig-Geo@r-project.org
https://stat.ethz.ch/mailman/listinfo/r-sig-geo

Re: [R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Danlin Yu]

l

depend on whether the OSM server is down or not (or busy).

I have to say that I used some years ago this app and nowadays I know

that

for some cities OSM has more streets reported than the same google maps.
Also is an open project and they let you download their data for free,
contrary to what google maps do.

All the best,


Andres

El vie., 21 jun. 2019 a las 4:30, Adrian Baddeley (<
adrian.badde...@curtin.edu.au>) escribió:


Rather than converting an object of class 'SpatialLines' or
'SpatialLinesDataFrame' to the spatstat class 'psp' and then

converting it

to the spatstat class 'linnet', it is safer and more efficient to

convert

the SpatialLines* object directly to class linnet using
as.linnet.SpatialLinesDataFrame() from the package 'maptools'.


Prof Adrian Baddeley DSc FAA

John Curtin Distinguished Professor

Department of Mathematics and Statistics

Curtin University, Perth, Western Australia



From: Rolf Turner 
Sent: Friday, 21 June 2019 10:08 AM
To: Rolando Valdez
Cc: r-sig-geo@r-project.org; Adrian Baddeley; Ege Rubak
Subject: Re: [FORGED] [R-sig-Geo] Create a Spatial Weight Matrix based

on

road distance


On 21/06/19 12:26 PM, Rolando Valdez wrote:


Dear community,

Is there any way to create a spatial weight matrix based on road

distance?

I am trying to use the road distance between two points instead of
euclidean distance.

I've seen that there is a package named osrm. Can anyone give some

advice?

I don't know anything about "osrm".  Calculating "road distances" can

be

done in the spatstat package reasonably easily, if you take the trouble
to represent your collection of roads as a "linnet" object.

Given that you have done so, suppose that your linnet object is "L" and
that you have vectors "x" and "y" specifying the points on L (i.e. on
your roads) between which you want to know the distances.

Do:

  X<- lpp(data.frame(x=x,y=y),L)
  dMat <- pairdist(X)

The object "dMat" is a (symmetric) square matrix; dMat[i,j] is the
distance between point i and point j.  (Of course the diagonal entries
are all 0.)

If your collection of roads is specified by means of a shapefile,
vignette("shapefiles") will tell you how to turn this collection into a
"psp" ("planar segment pattern") object; the function (method)
as.linnet.psp() can then be used to turn the "psp" object into a
"linnet" object.

HTH

cheers,

Rolf Turner

--
Honorary Research Fellow
Department of Statistics
University of Auckland
Phone: +64-9-373-7599 ext. 88276

 [[alternative HTML version deleted]]

___
R-sig-Geo mailing list
R-sig-Geo@r-project.org
https://stat.ethz.ch/mailman/listinfo/r-sig-geo



--
Andrés D.





--
Roger Bivand
Department of Economics, Norwegian School of Economics,
Helleveien 30, N-5045 Bergen, Norway.
voice: +47 55 95 93 55; e-mail: roger.biv...@nhh.no
https://orcid.org/-0003-2392-6140
https://scholar.google.no/citations?user=AWeghB0J=en




--
___
Danlin Yu, Ph.D.
Professor of GIS and Urban Geography
Department of Earth & Environmental Studies
Montclair State University
Montclair, NJ, 07043
Tel: 973-655-4313
Fax: 973-655-4072
Office: CELS 314
Email: y...@mail.montclair.edu
webpage: csam.montclair.edu/~yu

___
R-sig-Geo mailing list
R-sig-Geo@r-project.org
https://stat.ethz.ch/mailman/listinfo/r-sig-geo

Re: [R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Rolando Valdez]

gt;>> Rather than converting an object of class 'SpatialLines' or
> >>> 'SpatialLinesDataFrame' to the spatstat class 'psp' and then
> converting it
> >>> to the spatstat class 'linnet', it is safer and more efficient to
> convert
> >>> the SpatialLines* object directly to class linnet using
> >>> as.linnet.SpatialLinesDataFrame() from the package 'maptools'.
> >>>
> >>>
> >>> Prof Adrian Baddeley DSc FAA
> >>>
> >>> John Curtin Distinguished Professor
> >>>
> >>> Department of Mathematics and Statistics
> >>>
> >>> Curtin University, Perth, Western Australia
> >>>
> >>>
> >>> 
> >>> From: Rolf Turner 
> >>> Sent: Friday, 21 June 2019 10:08 AM
> >>> To: Rolando Valdez
> >>> Cc: r-sig-geo@r-project.org; Adrian Baddeley; Ege Rubak
> >>> Subject: Re: [FORGED] [R-sig-Geo] Create a Spatial Weight Matrix based
> on
> >>> road distance
> >>>
> >>>
> >>> On 21/06/19 12:26 PM, Rolando Valdez wrote:
> >>>
> >>>> Dear community,
> >>>>
> >>>> Is there any way to create a spatial weight matrix based on road
> >>> distance?
> >>>> I am trying to use the road distance between two points instead of
> >>>> euclidean distance.
> >>>>
> >>>> I've seen that there is a package named osrm. Can anyone give some
> >>> advice?
> >>>
> >>> I don't know anything about "osrm".  Calculating "road distances" can
> be
> >>> done in the spatstat package reasonably easily, if you take the trouble
> >>> to represent your collection of roads as a "linnet" object.
> >>>
> >>> Given that you have done so, suppose that your linnet object is "L" and
> >>> that you have vectors "x" and "y" specifying the points on L (i.e. on
> >>> your roads) between which you want to know the distances.
> >>>
> >>> Do:
> >>>
> >>>  X<- lpp(data.frame(x=x,y=y),L)
> >>>  dMat <- pairdist(X)
> >>>
> >>> The object "dMat" is a (symmetric) square matrix; dMat[i,j] is the
> >>> distance between point i and point j.  (Of course the diagonal entries
> >>> are all 0.)
> >>>
> >>> If your collection of roads is specified by means of a shapefile,
> >>> vignette("shapefiles") will tell you how to turn this collection into a
> >>> "psp" ("planar segment pattern") object; the function (method)
> >>> as.linnet.psp() can then be used to turn the "psp" object into a
> >>> "linnet" object.
> >>>
> >>> HTH
> >>>
> >>> cheers,
> >>>
> >>> Rolf Turner
> >>>
> >>> --
> >>> Honorary Research Fellow
> >>> Department of Statistics
> >>> University of Auckland
> >>> Phone: +64-9-373-7599 ext. 88276
> >>>
> >>> [[alternative HTML version deleted]]
> >>>
> >>> ___
> >>> R-sig-Geo mailing list
> >>> R-sig-Geo@r-project.org
> >>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
> >>>
> >>
> >>
> >> --
> >> Andrés D.
> >>
> >
> >
> >
>
> --
> Roger Bivand
> Department of Economics, Norwegian School of Economics,
> Helleveien 30, N-5045 Bergen, Norway.
> voice: +47 55 95 93 55; e-mail: roger.biv...@nhh.no
> https://orcid.org/-0003-2392-6140
> https://scholar.google.no/citations?user=AWeghB0J=en



-- 
Rol~

[[alternative HTML version deleted]]

___
R-sig-Geo mailing list
R-sig-Geo@r-project.org
https://stat.ethz.ch/mailman/listinfo/r-sig-geo

[R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Timothée Giraud]

Dear Rolando,

OSRM (Open Source Routing Machine) is a routing engine designed to run 
on OpenStreetMap data.

There is a public instance of the engine, a demo server. This server 
has limitations 
(https://github.com/Project-OSRM/osrm-backend/wiki/Demo-server) like 
the number of requests/minute, or in your case the maximum size of a 
requested distance matrix (1, meaning 100 origines x 100 
destinations).  As they say :"he demo server usage is restricted to 
reasonable, non-commercial use-cases. We provide no guarantees wrt. 
uptime, latency, or data updates."

A solution is to run your own instance of the server to get rid of 
these limitations. The prefered and simplest way to run an instance is 
to use a Docker container 
(https://github.com/Project-OSRM/osrm-backend#quick-start).
When launching the Docker you'll have to set a large value for the 
--max-table-size parameter. Something like:
docker run -t -i -p 5000:5000 -v "${PWD}:/data" osrm/osrm-backend 
osrm-routed --algorithm mld --max-table-size 900 
/data/berlin-latest.osrm

The osrm R package is an interface between R and OSRM. The default 
server used by the package is the OSRM demo server. But you can change 
the default server with :
options(osrm.server = "http://0.0.0.0:5000/;, osrm.profile = "driving")

Cheers,

Timothée



[[alternative HTML version deleted]]

___
R-sig-Geo mailing list
R-sig-Geo@r-project.org
https://stat.ethz.ch/mailman/listinfo/r-sig-geo

Re: [R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Roger Bivand]

On Mon, 24 Jun 2019, Rolando Valdez wrote:


Dear Andres,

I could follow an example provided with the package, it was a little bit
simple, however, I got this message:


dists <- osrmTable(loc = muns13, measure = "duration")

The OSRM server returned an error:
Error: The public OSRM API does not allow results with a number of
durations
higher than 1. Ask for fewer durations or use your own server and set
its
--max-table-size option.

My sample size is 2,457


Were you asking for the whole nx(n-1)/2 set of durations in one run? You 
see that the API limits the number of interactions (possibly by time and 
by unique IP number). So you need to reduce the number of queries. If you 
are going to impose a distance threshold anyway, you can do that using the 
Great Circle (not Euclidean) distances between your geographical 
coordinates and dnearneigh(), and step through the nb list object with 
src= being the data frame of the observation coordinates, and dest= the 
data frame of the neighbours' coordinates.


library(sf)
nc <- st_read(system.file("shapes/sids.shp", package="spData")[1], 
quiet=TRUE)

st_crs(nc) <- "+proj=longlat +datum=NAD27"
nc1 <- st_transform(nc, 32019)
nc2 <- st_centroid(nc1, of_largest_polygon=TRUE)
nc3 <- st_transform(nc2, 4326)
crds <- st_coordinates(st_geometry(nc3))
df <- data.frame(id=nc3$FIPSNO, long=crds[,1], lat=crds[,2])
library(spdep)
nb <- dnearneigh(crds, 0, 50, longlat=TRUE)
library(osrm)
res <- vector(mode="list", length=nrow(df))
for (i in seq(along=res)) res[[i]] <- osrmTable(src=df[i,],
 dst=df[nb[[i]],], measure = "duration")
res1 <- lapply(res, function(x) 10/x$duration)
lw <- nb2listw(nb, glist=res1, style="B")

gives general spatial weights based on 10/# minutes travel time between 
county centroids (centroids calculated from projected coordinates), for 
county centroids closer than 50 km measured by Great Circle.


In your case, you may need to split the for() loop into portions of 
cumsum(card(nb)) of less than the limit. If durations are symmetric, 
you could also halve the query count by taking only neighbour ids > i, 
but you'd have to fold them back afterwards. You also wanted to categorise 
the durations into 0,1, which you could do with lapply() instead of using 
inverse durations.


Hope this helps,

Roger



El vie., 21 de jun. de 2019 a la(s) 02:53, Andres Diaz Loaiza (
madi...@gmail.com) escribió:


Dear Rolando,

The advantage of using Open Street Maps engine is that you can give the
travel option. This means you can select whether are you traveling by bike,
car or walking. The previous approach didn't consider this topic. For this,
you should have added a vector layer depending on your position of the
street you can take (or not). Open Street Maps project allow you two
options: a service in which you give your current position, the position
you want to reach and your transport method (giving you back the fastest
route). Or the option to download the engine/algorithm compile by yourself
(if I am not wrong is made in C or python) and then you can make your own
calculation at your own computer. For the first option, the package OSRM is
an interface in which send a request to the OSM web page and wait for an
answer. With this method, you can send a couple of request at the same time
but no to many (you should read the manual for this). Of course, also will
depend on whether the OSM server is down or not (or busy).

I have to say that I used some years ago this app and nowadays I know that
for some cities OSM has more streets reported than the same google maps.
Also is an open project and they let you download their data for free,
contrary to what google maps do.

All the best,


Andres

El vie., 21 jun. 2019 a las 4:30, Adrian Baddeley (<
adrian.badde...@curtin.edu.au>) escribió:


Rather than converting an object of class 'SpatialLines' or
'SpatialLinesDataFrame' to the spatstat class 'psp' and then converting it
to the spatstat class 'linnet', it is safer and more efficient to convert
the SpatialLines* object directly to class linnet using
as.linnet.SpatialLinesDataFrame() from the package 'maptools'.


Prof Adrian Baddeley DSc FAA

John Curtin Distinguished Professor

Department of Mathematics and Statistics

Curtin University, Perth, Western Australia



From: Rolf Turner 
Sent: Friday, 21 June 2019 10:08 AM
To: Rolando Valdez
Cc: r-sig-geo@r-project.org; Adrian Baddeley; Ege Rubak
Subject: Re: [FORGED] [R-sig-Geo] Create a Spatial Weight Matrix based on
road distance


On 21/06/19 12:26 PM, Rolando Valdez wrote:


Dear community,

Is there any way to create a spatial weight matrix based on road

distance?

I am trying to use the road distance between two points instead of
euclidean distance.

I've seen that there is a package named osrm. Can anyone give some

advice?

I don't know anything abou

Re: [R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Rolando Valdez]

Dear Andres,

I could follow an example provided with the package, it was a little bit
simple, however, I got this message:

> dists <- osrmTable(loc = muns13, measure = "duration")
The OSRM server returned an error:
Error: The public OSRM API does not allow results with a number of
durations
higher than 1. Ask for fewer durations or use your own server and set
its
--max-table-size option.

My sample size is 2,457

El vie., 21 de jun. de 2019 a la(s) 02:53, Andres Diaz Loaiza (
madi...@gmail.com) escribió:

> Dear Rolando,
>
> The advantage of using Open Street Maps engine is that you can give the
> travel option. This means you can select whether are you traveling by bike,
> car or walking. The previous approach didn't consider this topic. For this,
> you should have added a vector layer depending on your position of the
> street you can take (or not). Open Street Maps project allow you two
> options: a service in which you give your current position, the position
> you want to reach and your transport method (giving you back the fastest
> route). Or the option to download the engine/algorithm compile by yourself
> (if I am not wrong is made in C or python) and then you can make your own
> calculation at your own computer. For the first option, the package OSRM is
> an interface in which send a request to the OSM web page and wait for an
> answer. With this method, you can send a couple of request at the same time
> but no to many (you should read the manual for this). Of course, also will
> depend on whether the OSM server is down or not (or busy).
>
> I have to say that I used some years ago this app and nowadays I know that
> for some cities OSM has more streets reported than the same google maps.
> Also is an open project and they let you download their data for free,
> contrary to what google maps do.
>
> All the best,
>
>
> Andres
>
> El vie., 21 jun. 2019 a las 4:30, Adrian Baddeley (<
> adrian.badde...@curtin.edu.au>) escribió:
>
>> Rather than converting an object of class 'SpatialLines' or
>> 'SpatialLinesDataFrame' to the spatstat class 'psp' and then converting it
>> to the spatstat class 'linnet', it is safer and more efficient to convert
>> the SpatialLines* object directly to class linnet using
>> as.linnet.SpatialLinesDataFrame() from the package 'maptools'.
>>
>>
>> Prof Adrian Baddeley DSc FAA
>>
>> John Curtin Distinguished Professor
>>
>> Department of Mathematics and Statistics
>>
>> Curtin University, Perth, Western Australia
>>
>>
>> ________________
>> From: Rolf Turner 
>> Sent: Friday, 21 June 2019 10:08 AM
>> To: Rolando Valdez
>> Cc: r-sig-geo@r-project.org; Adrian Baddeley; Ege Rubak
>> Subject: Re: [FORGED] [R-sig-Geo] Create a Spatial Weight Matrix based on
>> road distance
>>
>>
>> On 21/06/19 12:26 PM, Rolando Valdez wrote:
>>
>> > Dear community,
>> >
>> > Is there any way to create a spatial weight matrix based on road
>> distance?
>> > I am trying to use the road distance between two points instead of
>> > euclidean distance.
>> >
>> > I've seen that there is a package named osrm. Can anyone give some
>> advice?
>>
>> I don't know anything about "osrm".  Calculating "road distances" can be
>> done in the spatstat package reasonably easily, if you take the trouble
>> to represent your collection of roads as a "linnet" object.
>>
>> Given that you have done so, suppose that your linnet object is "L" and
>> that you have vectors "x" and "y" specifying the points on L (i.e. on
>> your roads) between which you want to know the distances.
>>
>> Do:
>>
>>  X<- lpp(data.frame(x=x,y=y),L)
>>  dMat <- pairdist(X)
>>
>> The object "dMat" is a (symmetric) square matrix; dMat[i,j] is the
>> distance between point i and point j.  (Of course the diagonal entries
>> are all 0.)
>>
>> If your collection of roads is specified by means of a shapefile,
>> vignette("shapefiles") will tell you how to turn this collection into a
>> "psp" ("planar segment pattern") object; the function (method)
>> as.linnet.psp() can then be used to turn the "psp" object into a
>> "linnet" object.
>>
>> HTH
>>
>> cheers,
>>
>> Rolf Turner
>>
>> --
>> Honorary Research Fellow
>> Department of Statistics
>> University of Auckland
>> Phone: +64-9-373-7599 ext. 88276
>>
>> [[alternative HTML version deleted]]
>>
>> ___
>> R-sig-Geo mailing list
>> R-sig-Geo@r-project.org
>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>>
>
>
> --
> Andrés D.
>


-- 
Rol~

[[alternative HTML version deleted]]

___
R-sig-Geo mailing list
R-sig-Geo@r-project.org
https://stat.ethz.ch/mailman/listinfo/r-sig-geo

Re: [R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Rolando Valdez]

El dom., 23 de jun. de 2019 a la(s) 03:00, Roger Bivand (roger.biv...@nhh.no)
escribió:

> Comments inline below:
>
> On Sun, 23 Jun 2019, Rolando Valdez wrote:
>
> > I apologize for the lack of clarity.
> >
> > Let me try again:
> >
> > The SWM captures the spatial structure among territories. In the case of
> a
> > matrix based on distance, you define a distance-threshold, say 50 km, and
> > every territory under that distance is considered as neighbor, in the
> > matrix, those territories considered neighbors take the value 1, and 0
> > otherwise (territories beyond 50 km). This is what 'dnearneigh' function
> > does.
> >
> > Then, I want to define a distance-threshold, say 50 km by road (not
> > euclidean) and every territory under that distance (by road) be
> considered
> > as neighbor.
>
>
> So the main goal is to use distance by road between territories to
> construct a neighbour object, with a maximum distance threshold.
>

Yes, just like that.

>
> Firstly, why do you suppose that this will represent your a priori
> knowledge better than contiguity, which is the most obvious measure of
> neighbourhood for data with areal support?
>

I'm running the same specification with 8 distance-threshold to assess the
impact of the distance on a key dependent variable.

>
> If there are major mountain chains or water bodies impeding contact across
> a boundary between contiguous territories, could you not just edit out
> those graph edges (spdep::edit.nb() for example)? If there are many, a
> programmatic approach may be needed.
>

Yes, there are many cases like this you mentioned.

>
> The inherent difficulty is that distances to territories in practice mean
> that you have to change support from area to point, and that needs
> thinking through. A territory centroid may, for example, not lie on a
> transport link. If you have finer scale population or production data, you
> might use weighted centroids, but this involves further steps, and using
> this kind of data may add endogeneity, as the variables used to define the
> neighbour object may enter your model elsewhere.
>

I have redefine the shapefile to urban areas, these polygons are smaller
than counties, thus, their centroids would lie on the roads more
confidently.

I am not using variables to define the neighbor object.

>
> So:
>
> I) explain why you cannot simply use contiguities (using accessibility as
> a covariate if important);
>

Because the distance is an explanatory component itself.

>
> II) if some contiguities given territory boundaries should be removed
> because there are good reasons (mountain range, ...) for no contact,
> provide a reproducible example so that you can be assisted in programming
> the criteria for thinning the contiguity graph; and
>
> III) if you really want to go with road distances, provide a reproducible
> example for first finding the representative point for each territory and
> then giving the road network and territory boundaries. With the linear
> network and the change-of-support points, it is not unlikely that the
> spatstat linnet route will be easiest to implement. I have used raster
> cost distances in GRASS for things like this (see the Snow example in ch.
> 4 in ASDAR); gdistance is slower in that setting.
>

I've seen the example you suggest, I cannot figure out how to fit to my case
.

>
> Hope this helps,
>
> Roger
>
> PS. It would be really helpful to use affiliations, as gmail addresses
> tell us nothing about what might be expected of background knowledge. This
> posting feels like someone looking for a response to a reviewer of an
> article submitted to a journal, where the reviewer has little idea of the
> underlying challenges involved in making such a revision. Not knowing
> this, and the lack of a reproducible example leaves helpers pretty much in
> the dark. Using existing or toy data sets lets you post without showing
> too much of the detail in your specific problem, but in this thread there
> has been too little information for reasonable traction.
>

You are absolutely right. I am trying to follow a suggestion from a
referee, who suggests to switch from the euclidean distance to a road
distance. This is the reason I posted my doubt, I had no clue even where to
start.

Now, I have task to do.

Thanks a lot for your help.


> >
> > El sáb., 22 de jun. de 2019 a la(s) 21:15, Rolf Turner (
> > r.tur...@auckland.ac.nz) escribió:
> >
> >> On 23/06/19 3:30 PM, Rolando Valdez wrote:
> >>> Sorry again.
> >>>
> >>> A Spatial Weight Matrix (swm) is an object used in spatial econometrics
> >>> to characterize the spatial structure among territories. It is an
> >>> element nxn where n is the number of territorial units (counties,
> >>> districts, states, cities, regions) in the sample and it could be based
> >>> on contiguity or distance. Usually, you can create a swm based on
> >>> distance using 'dnearneigh' from spdep and then convert to a listw
> >>> through 'nb2listw'. The problem is that the 

Re: [R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Rolando Valdez]

I mean the distance between centroids of polygons that represent counties.

Thank you for your time.

El dom., 23 de jun. de 2019 a la(s) 01:17, Rolf Turner (
r.tur...@auckland.ac.nz) escribió:

>
> On 23/06/19 6:01 PM, Rolando Valdez wrote:
>
> > I apologize for the lack of clarity.
> >
> > Let me try again:
> >
> > The SWM captures the spatial structure among territories. In the case of
> > a matrix based on distance, you define a distance-threshold, say 50 km,
> > and every territory under that distance is considered as neighbor, in
> > the matrix, those territories considered neighbors take the value 1, and
> > 0 otherwise (territories beyond 50 km). This is what 'dnearneigh'
> > function does.
> >
> > Then, I want to define a distance-threshold, say 50 km by road (not
> > euclidean) and every territory under that distance (by road) be
> > considered as neighbor.
>
> You still have not defined what you mean by *distance* between
> territories (regions, counties). Distance between *points* is well
> defined; distance between territories is not.  You have to specify what
> you mean by such a distance.  This could be the minimum distance between
> points in the regions (which is not of course a metric), distance
> between centroids of the territories, Hausdorff distance, or something
> else.  This applies whether you are talking about the distance between
> points being Euclidean distance or road distance or some other metric.
> Thresholding that distance (e.g. at 50 km.) is then a trivial matter.
>
> I have tried my best to get you to clarify what you mean, and my efforts
> seem to be in vain.  Since Juan Pablo thinks that I am "bullying you"
> (which mystifies me completely) I guess I'll give up.  And to respond to
> Juan Pablo's hope, nothing whatever is "bothering" me.
>
> cheers,
>
> Rolf
>
> >
> > El sáb., 22 de jun. de 2019 a la(s) 21:15, Rolf Turner
> > (r.tur...@auckland.ac.nz ) escribió:
> >
> > On 23/06/19 3:30 PM, Rolando Valdez wrote:
> >  > Sorry again.
> >  >
> >  > A Spatial Weight Matrix (swm) is an object used in spatial
> > econometrics
> >  > to characterize the spatial structure among territories. It is an
> >  > element nxn where n is the number of territorial units (counties,
> >  > districts, states, cities, regions) in the sample and it could be
> > based
> >  > on contiguity or distance. Usually, you can create a swm based on
> >  > distance using 'dnearneigh' from spdep and then convert to a listw
> >  > through 'nb2listw'. The problem is that the matrix that you
> generate
> >  > trough 'dnearneigh'computes the euclidean distance among
> > centroids of
> >  > polygons. This is where I spot my issue, I need to compute the
> > swm using
> >  > the road distance instead of euclidean distance computed through
> >  > 'dnearneigh'. I do have a shapefile with poligons (counties) and
> > another
> >  > shapefile with lines (roads).
> >
> > OK.  It's getting a *bit* clearer   You are interested in "road
> > distances" between counties.  I'm still not entirely sure what this
> > means.  Is it the *minimum* distance by road from one county to
> > another?
> > In which case, if two counties are contiguous (adjacent) and there
> is a
> > road crossing the border between the two, is the distance between the
> > counties equal to zero?  (This doesn't seem like it would be
> > satisfactory )
> >
> > Yes, actually it is possible that two counties were connected by more
> > than one road, however it's not a big deal. If I define a distance of 50
> > km, it doesn't matter how many times two counties are connected, I just
> > need that they are at 50 km trough, at least, one road.
> >
> > If this is not the case, then what *is* the case?  Perhaps you want
> > distances between the *centroids* of the counties.  What then do you
> > mean by road distance when the centroids do not lie on a road?
> >
> >
> > This is a big challenge, I'm still working on it.
> >
> >
> > You apparently need to deal with counties in which there are no
> > roads at
> > all.  To handle this you have to define what *you* mean by the
> distance
> > by road from county A to county B when there are no roads at all in
> > county B.  Perhaps infinity would be the appropriate distance, but
> *I*
> > don't know; you have to make the call.
> >
> >
> > If two counties are not connected through a road, they could not be
> > neighbors. In this case, it would correspond to a value 0 in the matrix.
> >
> >
> > Previously you indicated that you needed to know (pairwise) road
> > distances between specified points in a given set, and I showed you
> how
> > to obtain those using pairdist(), from spatstat.  Now it seems that
> you
> > want something rather different, and it's still not clear what.
> >
> > In a sense is the same, but you 

Re: [R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Roger Bivand]

Comments inline below:

On Sun, 23 Jun 2019, Rolando Valdez wrote:


I apologize for the lack of clarity.

Let me try again:

The SWM captures the spatial structure among territories. In the case of a
matrix based on distance, you define a distance-threshold, say 50 km, and
every territory under that distance is considered as neighbor, in the
matrix, those territories considered neighbors take the value 1, and 0
otherwise (territories beyond 50 km). This is what 'dnearneigh' function
does.

Then, I want to define a distance-threshold, say 50 km by road (not
euclidean) and every territory under that distance (by road) be considered
as neighbor.



So the main goal is to use distance by road between territories to 
construct a neighbour object, with a maximum distance threshold.


Firstly, why do you suppose that this will represent your a priori 
knowledge better than contiguity, which is the most obvious measure of 
neighbourhood for data with areal support?


If there are major mountain chains or water bodies impeding contact across 
a boundary between contiguous territories, could you not just edit out 
those graph edges (spdep::edit.nb() for example)? If there are many, a 
programmatic approach may be needed.


The inherent difficulty is that distances to territories in practice mean 
that you have to change support from area to point, and that needs 
thinking through. A territory centroid may, for example, not lie on a 
transport link. If you have finer scale population or production data, you 
might use weighted centroids, but this involves further steps, and using 
this kind of data may add endogeneity, as the variables used to define the 
neighbour object may enter your model elsewhere.


So:

I) explain why you cannot simply use contiguities (using accessibility as 
a covariate if important);


II) if some contiguities given territory boundaries should be removed 
because there are good reasons (mountain range, ...) for no contact, 
provide a reproducible example so that you can be assisted in programming 
the criteria for thinning the contiguity graph; and


III) if you really want to go with road distances, provide a reproducible 
example for first finding the representative point for each territory and 
then giving the road network and territory boundaries. With the linear 
network and the change-of-support points, it is not unlikely that the 
spatstat linnet route will be easiest to implement. I have used raster 
cost distances in GRASS for things like this (see the Snow example in ch. 
4 in ASDAR); gdistance is slower in that setting.


Hope this helps,

Roger

PS. It would be really helpful to use affiliations, as gmail addresses 
tell us nothing about what might be expected of background knowledge. This 
posting feels like someone looking for a response to a reviewer of an 
article submitted to a journal, where the reviewer has little idea of the 
underlying challenges involved in making such a revision. Not knowing 
this, and the lack of a reproducible example leaves helpers pretty much in 
the dark. Using existing or toy data sets lets you post without showing 
too much of the detail in your specific problem, but in this thread there 
has been too little information for reasonable traction.




El sáb., 22 de jun. de 2019 a la(s) 21:15, Rolf Turner (
r.tur...@auckland.ac.nz) escribió:


On 23/06/19 3:30 PM, Rolando Valdez wrote:

Sorry again.

A Spatial Weight Matrix (swm) is an object used in spatial econometrics
to characterize the spatial structure among territories. It is an
element nxn where n is the number of territorial units (counties,
districts, states, cities, regions) in the sample and it could be based
on contiguity or distance. Usually, you can create a swm based on
distance using 'dnearneigh' from spdep and then convert to a listw
through 'nb2listw'. The problem is that the matrix that you generate
trough 'dnearneigh'computes the euclidean distance among centroids of
polygons. This is where I spot my issue, I need to compute the swm using
the road distance instead of euclidean distance computed through
'dnearneigh'. I do have a shapefile with poligons (counties) and another
shapefile with lines (roads).


OK.  It's getting a *bit* clearer   You are interested in "road
distances" between counties.  I'm still not entirely sure what this
means.  Is it the *minimum* distance by road from one county to another?
In which case, if two counties are contiguous (adjacent) and there is a
road crossing the border between the two, is the distance between the
counties equal to zero?  (This doesn't seem like it would be
satisfactory )

Yes, actually it is possible that two counties were connected by more than

one road, however it's not a big deal. If I define a distance of 50 km, it
doesn't matter how many times two counties are connected, I just need that
they are at 50 km trough, at least, one road.


If this is not the case, then what *is* the case?  Perhaps you want
distances 

Re: [R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Rolf Turner]

On 23/06/19 6:01 PM, Rolando Valdez wrote:


I apologize for the lack of clarity.

Let me try again:

The SWM captures the spatial structure among territories. In the case of 
a matrix based on distance, you define a distance-threshold, say 50 km, 
and every territory under that distance is considered as neighbor, in 
the matrix, those territories considered neighbors take the value 1, and 
0 otherwise (territories beyond 50 km). This is what 'dnearneigh' 
function does.


Then, I want to define a distance-threshold, say 50 km by road (not 
euclidean) and every territory under that distance (by road) be 
considered as neighbor.


You still have not defined what you mean by *distance* between 
territories (regions, counties). Distance between *points* is well 
defined; distance between territories is not.  You have to specify what 
you mean by such a distance.  This could be the minimum distance between 
points in the regions (which is not of course a metric), distance 
between centroids of the territories, Hausdorff distance, or something 
else.  This applies whether you are talking about the distance between 
points being Euclidean distance or road distance or some other metric. 
Thresholding that distance (e.g. at 50 km.) is then a trivial matter.


I have tried my best to get you to clarify what you mean, and my efforts 
seem to be in vain.  Since Juan Pablo thinks that I am "bullying you" 
(which mystifies me completely) I guess I'll give up.  And to respond to 
Juan Pablo's hope, nothing whatever is "bothering" me.


cheers,

Rolf



El sáb., 22 de jun. de 2019 a la(s) 21:15, Rolf Turner 
(r.tur...@auckland.ac.nz ) escribió:


On 23/06/19 3:30 PM, Rolando Valdez wrote:
 > Sorry again.
 >
 > A Spatial Weight Matrix (swm) is an object used in spatial
econometrics
 > to characterize the spatial structure among territories. It is an
 > element nxn where n is the number of territorial units (counties,
 > districts, states, cities, regions) in the sample and it could be
based
 > on contiguity or distance. Usually, you can create a swm based on
 > distance using 'dnearneigh' from spdep and then convert to a listw
 > through 'nb2listw'. The problem is that the matrix that you generate
 > trough 'dnearneigh'computes the euclidean distance among
centroids of
 > polygons. This is where I spot my issue, I need to compute the
swm using
 > the road distance instead of euclidean distance computed through
 > 'dnearneigh'. I do have a shapefile with poligons (counties) and
another
 > shapefile with lines (roads).

OK.  It's getting a *bit* clearer   You are interested in "road
distances" between counties.  I'm still not entirely sure what this
means.  Is it the *minimum* distance by road from one county to
another?
In which case, if two counties are contiguous (adjacent) and there is a
road crossing the border between the two, is the distance between the
counties equal to zero?  (This doesn't seem like it would be
satisfactory )

Yes, actually it is possible that two counties were connected by more 
than one road, however it's not a big deal. If I define a distance of 50 
km, it doesn't matter how many times two counties are connected, I just 
need that they are at 50 km trough, at least, one road.


If this is not the case, then what *is* the case?  Perhaps you want
distances between the *centroids* of the counties.  What then do you
mean by road distance when the centroids do not lie on a road?


This is a big challenge, I'm still working on it.


You apparently need to deal with counties in which there are no
roads at
all.  To handle this you have to define what *you* mean by the distance
by road from county A to county B when there are no roads at all in
county B.  Perhaps infinity would be the appropriate distance, but *I*
don't know; you have to make the call.


If two counties are not connected through a road, they could not be 
neighbors. In this case, it would correspond to a value 0 in the matrix.



Previously you indicated that you needed to know (pairwise) road
distances between specified points in a given set, and I showed you how
to obtain those using pairdist(), from spatstat.  Now it seems that you
want something rather different, and it's still not clear what.

In a sense is the same, but you said so properly, We have different 
research fields.


You need to get *your* thoughts clear; make some definitions and
specifications, and decide what you really want or need.


I got it.


It seems that you are expecting R to magically do your thinking for
you;
it won't!

No, I'm not expecting that.

cheers,

Rolf

 > El sáb., 22 de jun. de 2019 a la(s) 20:00, Rolf Turner
 > (r.tur...@auckland.ac.nz 

Re: [R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Juan Pablo Carranza]

Rolando, thanks for clarify.
"gdistance" may give you what you are looking for. Another option is the
package "osrm", for calculate distances using Open Street Maps routes.
Once you calculate a dataframe with the distances of every pair of
locations, you could make ones and ceros with a simple ifelse. Then you
could standarize by row. That will be your lw matrix.
Here is some help:

https://www.google.com/url?sa=t=web=j=https://cran.r-project.org/web/packages/gdistance/vignettes/gdistance1.pdf=2ahUKEwim8u3P-f7iAhV5GLkGHbUKBCUQFjAAegQIAxAB=AOvVaw2EjdceAFDJB9Qet-EBEDAn=1561271237676


Juan Pablo Carranza
Mgter. en Administración Pública
Lic. en Economía

El dom., 23 de jun. de 2019 3:02 a. m., Rolando Valdez 
escribió:

> I apologize for the lack of clarity.
>
> Let me try again:
>
> The SWM captures the spatial structure among territories. In the case of a
> matrix based on distance, you define a distance-threshold, say 50 km, and
> every territory under that distance is considered as neighbor, in the
> matrix, those territories considered neighbors take the value 1, and 0
> otherwise (territories beyond 50 km). This is what 'dnearneigh' function
> does.
>
> Then, I want to define a distance-threshold, say 50 km by road (not
> euclidean) and every territory under that distance (by road) be considered
> as neighbor.
>
> El sáb., 22 de jun. de 2019 a la(s) 21:15, Rolf Turner (
> r.tur...@auckland.ac.nz) escribió:
>
> > On 23/06/19 3:30 PM, Rolando Valdez wrote:
> > > Sorry again.
> > >
> > > A Spatial Weight Matrix (swm) is an object used in spatial econometrics
> > > to characterize the spatial structure among territories. It is an
> > > element nxn where n is the number of territorial units (counties,
> > > districts, states, cities, regions) in the sample and it could be based
> > > on contiguity or distance. Usually, you can create a swm based on
> > > distance using 'dnearneigh' from spdep and then convert to a listw
> > > through 'nb2listw'. The problem is that the matrix that you generate
> > > trough 'dnearneigh'computes the euclidean distance among centroids of
> > > polygons. This is where I spot my issue, I need to compute the swm
> using
> > > the road distance instead of euclidean distance computed through
> > > 'dnearneigh'. I do have a shapefile with poligons (counties) and
> another
> > > shapefile with lines (roads).
> >
> > OK.  It's getting a *bit* clearer   You are interested in "road
> > distances" between counties.  I'm still not entirely sure what this
> > means.  Is it the *minimum* distance by road from one county to another?
> > In which case, if two counties are contiguous (adjacent) and there is a
> > road crossing the border between the two, is the distance between the
> > counties equal to zero?  (This doesn't seem like it would be
> > satisfactory )
> >
> > Yes, actually it is possible that two counties were connected by more
> than
> one road, however it's not a big deal. If I define a distance of 50 km, it
> doesn't matter how many times two counties are connected, I just need that
> they are at 50 km trough, at least, one road.
>
> > If this is not the case, then what *is* the case?  Perhaps you want
> > distances between the *centroids* of the counties.  What then do you
> > mean by road distance when the centroids do not lie on a road?
> >
>
> This is a big challenge, I'm still working on it.
>
> >
> > You apparently need to deal with counties in which there are no roads at
> > all.  To handle this you have to define what *you* mean by the distance
> > by road from county A to county B when there are no roads at all in
> > county B.  Perhaps infinity would be the appropriate distance, but *I*
> > don't know; you have to make the call.
> >
>
> If two counties are not connected through a road, they could not be
> neighbors. In this case, it would correspond to a value 0 in the matrix.
>
> >
> > Previously you indicated that you needed to know (pairwise) road
> > distances between specified points in a given set, and I showed you how
> > to obtain those using pairdist(), from spatstat.  Now it seems that you
> > want something rather different, and it's still not clear what.
> >
> > In a sense is the same, but you said so properly, We have different
> research fields.
>
>
> > You need to get *your* thoughts clear; make some definitions and
> > specifications, and decide what you really want or need.
> >
>
> I got it.
>
> >
> > It seems that you are expecting R to magically do your thinking for you;
> > it won't!
> >
> > No, I'm not expecting that.
>
> > cheers,
> >
> > Rolf
> >
> > > El sáb., 22 de jun. de 2019 a la(s) 20:00, Rolf Turner
> > > (r.tur...@auckland.ac.nz ) escribió:
> > >
> > >
> > > On 23/06/19 2:38 PM, Rolando Valdez wrote:
> > >
> > >  > I am sorry, I was not clear enough. My goal is to calculate a
> > > spatial
> > >  > weight matrix (nxn) across counties but, instead of euclidean
> > > distance,
> 

Re: [R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Rolando Valdez]

I don't know how exactly works that, but I will try.

Thank you.

El sáb., 22 de jun. de 2019 a la(s) 22:17, Juan Pablo Carranza (
carranzaju...@gmail.com) escribió:

> Hi all!
> I don't have the specific answer, but I don't appreciate academic bullying
> either. So... here is a way you could take. Go to qgis, calculate road
> distances by network analysis and then add it to your dataframe. Use this
> new variable to weigth the matrix.
> I hope this serves, and I hope Rolf solves what ever is bothering *him*.
> Cheers
>
> Juan Pablo Carranza
> Mgter. en Administración Pública
> Lic. en Economía
>
> El dom., 23 de jun. de 2019 1:16 a. m., Rolf Turner <
> r.tur...@auckland.ac.nz> escribió:
>
>> On 23/06/19 3:30 PM, Rolando Valdez wrote:
>> > Sorry again.
>> >
>> > A Spatial Weight Matrix (swm) is an object used in spatial econometrics
>> > to characterize the spatial structure among territories. It is an
>> > element nxn where n is the number of territorial units (counties,
>> > districts, states, cities, regions) in the sample and it could be based
>> > on contiguity or distance. Usually, you can create a swm based on
>> > distance using 'dnearneigh' from spdep and then convert to a listw
>> > through 'nb2listw'. The problem is that the matrix that you generate
>> > trough 'dnearneigh'computes the euclidean distance among centroids of
>> > polygons. This is where I spot my issue, I need to compute the swm
>> using
>> > the road distance instead of euclidean distance computed through
>> > 'dnearneigh'. I do have a shapefile with poligons (counties) and
>> another
>> > shapefile with lines (roads).
>>
>> OK.  It's getting a *bit* clearer   You are interested in "road
>> distances" between counties.  I'm still not entirely sure what this
>> means.  Is it the *minimum* distance by road from one county to another?
>> In which case, if two counties are contiguous (adjacent) and there is a
>> road crossing the border between the two, is the distance between the
>> counties equal to zero?  (This doesn't seem like it would be
>> satisfactory )
>>
>> If this is not the case, then what *is* the case?  Perhaps you want
>> distances between the *centroids* of the counties.  What then do you
>> mean by road distance when the centroids do not lie on a road?
>>
>> You apparently need to deal with counties in which there are no roads at
>> all.  To handle this you have to define what *you* mean by the distance
>> by road from county A to county B when there are no roads at all in
>> county B.  Perhaps infinity would be the appropriate distance, but *I*
>> don't know; you have to make the call.
>>
>> Previously you indicated that you needed to know (pairwise) road
>> distances between specified points in a given set, and I showed you how
>> to obtain those using pairdist(), from spatstat.  Now it seems that you
>> want something rather different, and it's still not clear what.
>>
>> You need to get *your* thoughts clear; make some definitions and
>> specifications, and decide what you really want or need.
>>
>> It seems that you are expecting R to magically do your thinking for you;
>> it won't!
>>
>> cheers,
>>
>> Rolf
>>
>> > El sáb., 22 de jun. de 2019 a la(s) 20:00, Rolf Turner
>> > (r.tur...@auckland.ac.nz ) escribió:
>> >
>> >
>> > On 23/06/19 2:38 PM, Rolando Valdez wrote:
>> >
>> >  > I am sorry, I was not clear enough. My goal is to calculate a
>> > spatial
>> >  > weight matrix (nxn) across counties but, instead of euclidean
>> > distance,
>> >  > to use road distance.
>> >
>> > I'm afraid I still don't understand.  To put it mildly. You
>> presumably
>> > have a clear idea of what you are trying to, but those of us who are
>> > not
>> > involved in your research have no such idea.  We (or at least I)
>> > haven't
>> > a clue as to what you are talking about.
>> >
>> > What do you mean by "spatial weight"?  What are these weights used
>> for?
>> > What is n?  How are the counties involved?  Is n the number of
>> > counties?
>> > Are you interested in the road distance (minimum road distance?)
>> > between
>> > pairs of counties?
>> >
>> > Please explain *clearly* and do not expect those who are trying to
>> help
>> > you to be mind-readers!!!
>> >
>> > cheers,
>> >
>> > Rolf
>> >
>> >  >
>> >  > El sáb., 22 de jun. de 2019 a la(s) 19:28, Rolf Turner
>> >  > (r.tur...@auckland.ac.nz 
>> > >)
>> > escribió:
>> >  >
>> >  >
>> >  > On 23/06/19 1:17 PM, Rolando Valdez wrote:
>> >  >
>> >  >  > Thank you for your answer.
>> >  >  >
>> >  >  > I have a shapefile with, say, counties, and I got another
>> >  > shapefile with
>> >  >  > the roads. ¿What if a county does not intersect any road?
>> >  >
>> >  > I 

Re: [R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Rolando Valdez]

I apologize for the lack of clarity.

Let me try again:

The SWM captures the spatial structure among territories. In the case of a
matrix based on distance, you define a distance-threshold, say 50 km, and
every territory under that distance is considered as neighbor, in the
matrix, those territories considered neighbors take the value 1, and 0
otherwise (territories beyond 50 km). This is what 'dnearneigh' function
does.

Then, I want to define a distance-threshold, say 50 km by road (not
euclidean) and every territory under that distance (by road) be considered
as neighbor.

El sáb., 22 de jun. de 2019 a la(s) 21:15, Rolf Turner (
r.tur...@auckland.ac.nz) escribió:

> On 23/06/19 3:30 PM, Rolando Valdez wrote:
> > Sorry again.
> >
> > A Spatial Weight Matrix (swm) is an object used in spatial econometrics
> > to characterize the spatial structure among territories. It is an
> > element nxn where n is the number of territorial units (counties,
> > districts, states, cities, regions) in the sample and it could be based
> > on contiguity or distance. Usually, you can create a swm based on
> > distance using 'dnearneigh' from spdep and then convert to a listw
> > through 'nb2listw'. The problem is that the matrix that you generate
> > trough 'dnearneigh'computes the euclidean distance among centroids of
> > polygons. This is where I spot my issue, I need to compute the swm using
> > the road distance instead of euclidean distance computed through
> > 'dnearneigh'. I do have a shapefile with poligons (counties) and another
> > shapefile with lines (roads).
>
> OK.  It's getting a *bit* clearer   You are interested in "road
> distances" between counties.  I'm still not entirely sure what this
> means.  Is it the *minimum* distance by road from one county to another?
> In which case, if two counties are contiguous (adjacent) and there is a
> road crossing the border between the two, is the distance between the
> counties equal to zero?  (This doesn't seem like it would be
> satisfactory )
>
> Yes, actually it is possible that two counties were connected by more than
one road, however it's not a big deal. If I define a distance of 50 km, it
doesn't matter how many times two counties are connected, I just need that
they are at 50 km trough, at least, one road.

> If this is not the case, then what *is* the case?  Perhaps you want
> distances between the *centroids* of the counties.  What then do you
> mean by road distance when the centroids do not lie on a road?
>

This is a big challenge, I'm still working on it.

>
> You apparently need to deal with counties in which there are no roads at
> all.  To handle this you have to define what *you* mean by the distance
> by road from county A to county B when there are no roads at all in
> county B.  Perhaps infinity would be the appropriate distance, but *I*
> don't know; you have to make the call.
>

If two counties are not connected through a road, they could not be
neighbors. In this case, it would correspond to a value 0 in the matrix.

>
> Previously you indicated that you needed to know (pairwise) road
> distances between specified points in a given set, and I showed you how
> to obtain those using pairdist(), from spatstat.  Now it seems that you
> want something rather different, and it's still not clear what.
>
> In a sense is the same, but you said so properly, We have different
research fields.


> You need to get *your* thoughts clear; make some definitions and
> specifications, and decide what you really want or need.
>

I got it.

>
> It seems that you are expecting R to magically do your thinking for you;
> it won't!
>
> No, I'm not expecting that.

> cheers,
>
> Rolf
>
> > El sáb., 22 de jun. de 2019 a la(s) 20:00, Rolf Turner
> > (r.tur...@auckland.ac.nz ) escribió:
> >
> >
> > On 23/06/19 2:38 PM, Rolando Valdez wrote:
> >
> >  > I am sorry, I was not clear enough. My goal is to calculate a
> > spatial
> >  > weight matrix (nxn) across counties but, instead of euclidean
> > distance,
> >  > to use road distance.
> >
> > I'm afraid I still don't understand.  To put it mildly. You
> presumably
> > have a clear idea of what you are trying to, but those of us who are
> > not
> > involved in your research have no such idea.  We (or at least I)
> > haven't
> > a clue as to what you are talking about.
> >
> > What do you mean by "spatial weight"?  What are these weights used
> for?
> > What is n?  How are the counties involved?  Is n the number of
> > counties?
> > Are you interested in the road distance (minimum road distance?)
> > between
> > pairs of counties?
> >
> > Please explain *clearly* and do not expect those who are trying to
> help
> > you to be mind-readers!!!
> >
> > cheers,
> >
> > Rolf
> >
> >  >
> >  > El sáb., 22 de jun. de 2019 a la(s) 19:28, Rolf Turner
> >  > (r.tur...@auckland.ac.nz 

Re: [R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Juan Pablo Carranza]

Hi all!
I don't have the specific answer, but I don't appreciate academic bullying
either. So... here is a way you could take. Go to qgis, calculate road
distances by network analysis and then add it to your dataframe. Use this
new variable to weigth the matrix.
I hope this serves, and I hope Rolf solves what ever is bothering *him*.
Cheers

Juan Pablo Carranza
Mgter. en Administración Pública
Lic. en Economía

El dom., 23 de jun. de 2019 1:16 a. m., Rolf Turner 
escribió:

> On 23/06/19 3:30 PM, Rolando Valdez wrote:
> > Sorry again.
> >
> > A Spatial Weight Matrix (swm) is an object used in spatial econometrics
> > to characterize the spatial structure among territories. It is an
> > element nxn where n is the number of territorial units (counties,
> > districts, states, cities, regions) in the sample and it could be based
> > on contiguity or distance. Usually, you can create a swm based on
> > distance using 'dnearneigh' from spdep and then convert to a listw
> > through 'nb2listw'. The problem is that the matrix that you generate
> > trough 'dnearneigh'computes the euclidean distance among centroids of
> > polygons. This is where I spot my issue, I need to compute the swm using
> > the road distance instead of euclidean distance computed through
> > 'dnearneigh'. I do have a shapefile with poligons (counties) and another
> > shapefile with lines (roads).
>
> OK.  It's getting a *bit* clearer   You are interested in "road
> distances" between counties.  I'm still not entirely sure what this
> means.  Is it the *minimum* distance by road from one county to another?
> In which case, if two counties are contiguous (adjacent) and there is a
> road crossing the border between the two, is the distance between the
> counties equal to zero?  (This doesn't seem like it would be
> satisfactory )
>
> If this is not the case, then what *is* the case?  Perhaps you want
> distances between the *centroids* of the counties.  What then do you
> mean by road distance when the centroids do not lie on a road?
>
> You apparently need to deal with counties in which there are no roads at
> all.  To handle this you have to define what *you* mean by the distance
> by road from county A to county B when there are no roads at all in
> county B.  Perhaps infinity would be the appropriate distance, but *I*
> don't know; you have to make the call.
>
> Previously you indicated that you needed to know (pairwise) road
> distances between specified points in a given set, and I showed you how
> to obtain those using pairdist(), from spatstat.  Now it seems that you
> want something rather different, and it's still not clear what.
>
> You need to get *your* thoughts clear; make some definitions and
> specifications, and decide what you really want or need.
>
> It seems that you are expecting R to magically do your thinking for you;
> it won't!
>
> cheers,
>
> Rolf
>
> > El sáb., 22 de jun. de 2019 a la(s) 20:00, Rolf Turner
> > (r.tur...@auckland.ac.nz ) escribió:
> >
> >
> > On 23/06/19 2:38 PM, Rolando Valdez wrote:
> >
> >  > I am sorry, I was not clear enough. My goal is to calculate a
> > spatial
> >  > weight matrix (nxn) across counties but, instead of euclidean
> > distance,
> >  > to use road distance.
> >
> > I'm afraid I still don't understand.  To put it mildly. You
> presumably
> > have a clear idea of what you are trying to, but those of us who are
> > not
> > involved in your research have no such idea.  We (or at least I)
> > haven't
> > a clue as to what you are talking about.
> >
> > What do you mean by "spatial weight"?  What are these weights used
> for?
> > What is n?  How are the counties involved?  Is n the number of
> > counties?
> > Are you interested in the road distance (minimum road distance?)
> > between
> > pairs of counties?
> >
> > Please explain *clearly* and do not expect those who are trying to
> help
> > you to be mind-readers!!!
> >
> > cheers,
> >
> > Rolf
> >
> >  >
> >  > El sáb., 22 de jun. de 2019 a la(s) 19:28, Rolf Turner
> >  > (r.tur...@auckland.ac.nz 
> > >)
> > escribió:
> >  >
> >  >
> >  > On 23/06/19 1:17 PM, Rolando Valdez wrote:
> >  >
> >  >  > Thank you for your answer.
> >  >  >
> >  >  > I have a shapefile with, say, counties, and I got another
> >  > shapefile with
> >  >  > the roads. ¿What if a county does not intersect any road?
> >  >
> >  > I am sorry, but it is not at all clear to me just what the
> > problem is.
> >  > How do the counties come into the picture?  You said you
> > wanted to get
> >  > the road distance between points on the roads.  What have the
> > counties
> >  > got to do with this?
> >  >
> >  > 

Re: [R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Rolf Turner]

On 23/06/19 3:30 PM, Rolando Valdez wrote:

Sorry again.

A Spatial Weight Matrix (swm) is an object used in spatial econometrics 
to characterize the spatial structure among territories. It is an 
element nxn where n is the number of territorial units (counties, 
districts, states, cities, regions) in the sample and it could be based 
on contiguity or distance. Usually, you can create a swm based on 
distance using 'dnearneigh' from spdep and then convert to a listw 
through 'nb2listw'. The problem is that the matrix that you generate 
trough 'dnearneigh'computes the euclidean distance among centroids of 
polygons. This is where I spot my issue, I need to compute the swm using 
the road distance instead of euclidean distance computed through 
'dnearneigh'. I do have a shapefile with poligons (counties) and another 
shapefile with lines (roads).


OK.  It's getting a *bit* clearer   You are interested in "road 
distances" between counties.  I'm still not entirely sure what this 
means.  Is it the *minimum* distance by road from one county to another? 
In which case, if two counties are contiguous (adjacent) and there is a 
road crossing the border between the two, is the distance between the 
counties equal to zero?  (This doesn't seem like it would be 
satisfactory )


If this is not the case, then what *is* the case?  Perhaps you want 
distances between the *centroids* of the counties.  What then do you 
mean by road distance when the centroids do not lie on a road?


You apparently need to deal with counties in which there are no roads at 
all.  To handle this you have to define what *you* mean by the distance 
by road from county A to county B when there are no roads at all in 
county B.  Perhaps infinity would be the appropriate distance, but *I* 
don't know; you have to make the call.


Previously you indicated that you needed to know (pairwise) road 
distances between specified points in a given set, and I showed you how 
to obtain those using pairdist(), from spatstat.  Now it seems that you 
want something rather different, and it's still not clear what.


You need to get *your* thoughts clear; make some definitions and 
specifications, and decide what you really want or need.


It seems that you are expecting R to magically do your thinking for you; 
it won't!


cheers,

Rolf

El sáb., 22 de jun. de 2019 a la(s) 20:00, Rolf Turner 
(r.tur...@auckland.ac.nz ) escribió:



On 23/06/19 2:38 PM, Rolando Valdez wrote:

 > I am sorry, I was not clear enough. My goal is to calculate a
spatial
 > weight matrix (nxn) across counties but, instead of euclidean
distance,
 > to use road distance.

I'm afraid I still don't understand.  To put it mildly. You presumably
have a clear idea of what you are trying to, but those of us who are
not
involved in your research have no such idea.  We (or at least I)
haven't
a clue as to what you are talking about.

What do you mean by "spatial weight"?  What are these weights used for?
What is n?  How are the counties involved?  Is n the number of
counties?
Are you interested in the road distance (minimum road distance?)
between
pairs of counties?

Please explain *clearly* and do not expect those who are trying to help
you to be mind-readers!!!

cheers,

Rolf

 >
 > El sáb., 22 de jun. de 2019 a la(s) 19:28, Rolf Turner
 > (r.tur...@auckland.ac.nz 
>)
escribió:
 >
 >
 >     On 23/06/19 1:17 PM, Rolando Valdez wrote:
 >
 >      > Thank you for your answer.
 >      >
 >      > I have a shapefile with, say, counties, and I got another
 >     shapefile with
 >      > the roads. ¿What if a county does not intersect any road?
 >
 >     I am sorry, but it is not at all clear to me just what the
problem is.
 >     How do the counties come into the picture?  You said you
wanted to get
 >     the road distance between points on the roads.  What have the
counties
 >     got to do with this?
 >
 >     Can you perhaps provide a reproducible example?
 >
 >     cheers,
 >
 >     Rolf
 >
 >      >
 >      > El jue., 20 de jun. de 2019 a la(s) 19:08, Rolf Turner
 >      > (r.tur...@auckland.ac.nz 
>
 >      >>)
 >     escribió:
 >      >
 >      >
 >      >     On 21/06/19 12:26 PM, Rolando Valdez wrote:
 >      >
 >      >      > Dear community,
 >      >      >
 >      >      > Is there any way to create a spatial weight matrix
based
 >     on road
 >      >     

Re: [R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Rolando Valdez]

Sorry again.

A Spatial Weight Matrix (swm) is an object used in spatial econometrics to
characterize the spatial structure among territories. It is an element nxn
where n is the number of territorial units (counties, districts, states,
cities, regions) in the sample and it could be based on contiguity or
distance. Usually, you can create a swm based on distance using
'dnearneigh' from spdep and then convert to a listw through 'nb2listw'. The
problem is that the matrix that you generate trough 'dnearneigh'computes
the euclidean distance among centroids of polygons. This is where I spot my
issue, I need to compute the swm using the road distance instead of
euclidean distance computed through 'dnearneigh'. I do have a shapefile
with poligons (counties) and another shapefile with lines (roads).


El sáb., 22 de jun. de 2019 a la(s) 20:00, Rolf Turner (
r.tur...@auckland.ac.nz) escribió:

>
> On 23/06/19 2:38 PM, Rolando Valdez wrote:
>
> > I am sorry, I was not clear enough. My goal is to calculate a spatial
> > weight matrix (nxn) across counties but, instead of euclidean distance,
> > to use road distance.
>
> I'm afraid I still don't understand.  To put it mildly. You presumably
> have a clear idea of what you are trying to, but those of us who are not
> involved in your research have no such idea.  We (or at least I) haven't
> a clue as to what you are talking about.
>
> What do you mean by "spatial weight"?  What are these weights used for?
> What is n?  How are the counties involved?  Is n the number of counties?
> Are you interested in the road distance (minimum road distance?) between
> pairs of counties?
>
> Please explain *clearly* and do not expect those who are trying to help
> you to be mind-readers!!!
>
> cheers,
>
> Rolf
>
> >
> > El sáb., 22 de jun. de 2019 a la(s) 19:28, Rolf Turner
> > (r.tur...@auckland.ac.nz ) escribió:
> >
> >
> > On 23/06/19 1:17 PM, Rolando Valdez wrote:
> >
> >  > Thank you for your answer.
> >  >
> >  > I have a shapefile with, say, counties, and I got another
> > shapefile with
> >  > the roads. ¿What if a county does not intersect any road?
> >
> > I am sorry, but it is not at all clear to me just what the problem
> is.
> > How do the counties come into the picture?  You said you wanted to
> get
> > the road distance between points on the roads.  What have the
> counties
> > got to do with this?
> >
> > Can you perhaps provide a reproducible example?
> >
> > cheers,
> >
> > Rolf
> >
> >  >
> >  > El jue., 20 de jun. de 2019 a la(s) 19:08, Rolf Turner
> >  > (r.tur...@auckland.ac.nz 
> > >)
> > escribió:
> >  >
> >  >
> >  > On 21/06/19 12:26 PM, Rolando Valdez wrote:
> >  >
> >  >  > Dear community,
> >  >  >
> >  >  > Is there any way to create a spatial weight matrix based
> > on road
> >  > distance?
> >  >  > I am trying to use the road distance between two points
> > instead of
> >  >  > euclidean distance.
> >  >  >
> >  >  > I've seen that there is a package named osrm. Can anyone
> give
> >  > some advice?
> >  >
> >  > I don't know anything about "osrm".  Calculating "road
> distances"
> >  > can be
> >  > done in the spatstat package reasonably easily, if you take
> > the trouble
> >  > to represent your collection of roads as a "linnet" object.
> >  >
> >  > Given that you have done so, suppose that your linnet object
> > is "L" and
> >  > that you have vectors "x" and "y" specifying the points on L
> > (i.e. on
> >  > your roads) between which you want to know the distances.
> >  >
> >  > Do:
> >  >
> >  >   X<- lpp(data.frame(x=x,y=y),L)
> >  >   dMat <- pairdist(X)
> >  >
> >  > The object "dMat" is a (symmetric) square matrix; dMat[i,j]
> > is the
> >  > distance between point i and point j.  (Of course the
> > diagonal entries
> >  > are all 0.)
> >  >
> >  > If your collection of roads is specified by means of a
> shapefile,
> >  > vignette("shapefiles") will tell you how to turn this
> > collection into a
> >  > "psp" ("planar segment pattern") object; the function (method)
> >  > as.linnet.psp() can then be used to turn the "psp" object
> into a
> >  > "linnet" object.
> >  >
> >  > HTH
>


-- 
Rol~

[[alternative HTML version deleted]]

___
R-sig-Geo mailing list
R-sig-Geo@r-project.org
https://stat.ethz.ch/mailman/listinfo/r-sig-geo

Re: [R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Rolf Turner]

On 23/06/19 2:38 PM, Rolando Valdez wrote:

I am sorry, I was not clear enough. My goal is to calculate a spatial 
weight matrix (nxn) across counties but, instead of euclidean distance, 
to use road distance.


I'm afraid I still don't understand.  To put it mildly. You presumably 
have a clear idea of what you are trying to, but those of us who are not 
involved in your research have no such idea.  We (or at least I) haven't 
a clue as to what you are talking about.


What do you mean by "spatial weight"?  What are these weights used for? 
What is n?  How are the counties involved?  Is n the number of counties? 
Are you interested in the road distance (minimum road distance?) between 
pairs of counties?


Please explain *clearly* and do not expect those who are trying to help 
you to be mind-readers!!!


cheers,

Rolf



El sáb., 22 de jun. de 2019 a la(s) 19:28, Rolf Turner 
(r.tur...@auckland.ac.nz ) escribió:



On 23/06/19 1:17 PM, Rolando Valdez wrote:

 > Thank you for your answer.
 >
 > I have a shapefile with, say, counties, and I got another
shapefile with
 > the roads. ¿What if a county does not intersect any road?

I am sorry, but it is not at all clear to me just what the problem is.
How do the counties come into the picture?  You said you wanted to get
the road distance between points on the roads.  What have the counties
got to do with this?

Can you perhaps provide a reproducible example?

cheers,

Rolf

 >
 > El jue., 20 de jun. de 2019 a la(s) 19:08, Rolf Turner
 > (r.tur...@auckland.ac.nz 
>)
escribió:
 >
 >
 >     On 21/06/19 12:26 PM, Rolando Valdez wrote:
 >
 >      > Dear community,
 >      >
 >      > Is there any way to create a spatial weight matrix based
on road
 >     distance?
 >      > I am trying to use the road distance between two points
instead of
 >      > euclidean distance.
 >      >
 >      > I've seen that there is a package named osrm. Can anyone give
 >     some advice?
 >
 >     I don't know anything about "osrm".  Calculating "road distances"
 >     can be
 >     done in the spatstat package reasonably easily, if you take
the trouble
 >     to represent your collection of roads as a "linnet" object.
 >
 >     Given that you have done so, suppose that your linnet object
is "L" and
 >     that you have vectors "x" and "y" specifying the points on L
(i.e. on
 >     your roads) between which you want to know the distances.
 >
 >     Do:
 >
 >           X    <- lpp(data.frame(x=x,y=y),L)
 >           dMat <- pairdist(X)
 >
 >     The object "dMat" is a (symmetric) square matrix; dMat[i,j]
is the
 >     distance between point i and point j.  (Of course the
diagonal entries
 >     are all 0.)
 >
 >     If your collection of roads is specified by means of a shapefile,
 >     vignette("shapefiles") will tell you how to turn this
collection into a
 >     "psp" ("planar segment pattern") object; the function (method)
 >     as.linnet.psp() can then be used to turn the "psp" object into a
 >     "linnet" object.
 >
 >     HTH


___
R-sig-Geo mailing list
R-sig-Geo@r-project.org
https://stat.ethz.ch/mailman/listinfo/r-sig-geo

Re: [R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Rolando Valdez]

I am sorry, I was not clear enough. My goal is to calculate a spatial
weight matrix (nxn) across counties but, instead of euclidean distance, to
use road distance.

El sáb., 22 de jun. de 2019 a la(s) 19:28, Rolf Turner (
r.tur...@auckland.ac.nz) escribió:

>
> On 23/06/19 1:17 PM, Rolando Valdez wrote:
>
> > Thank you for your answer.
> >
> > I have a shapefile with, say, counties, and I got another shapefile with
> > the roads. ¿What if a county does not intersect any road?
>
> I am sorry, but it is not at all clear to me just what the problem is.
> How do the counties come into the picture?  You said you wanted to get
> the road distance between points on the roads.  What have the counties
> got to do with this?
>
> Can you perhaps provide a reproducible example?
>
> cheers,
>
> Rolf
>
> >
> > El jue., 20 de jun. de 2019 a la(s) 19:08, Rolf Turner
> > (r.tur...@auckland.ac.nz ) escribió:
> >
> >
> > On 21/06/19 12:26 PM, Rolando Valdez wrote:
> >
> >  > Dear community,
> >  >
> >  > Is there any way to create a spatial weight matrix based on road
> > distance?
> >  > I am trying to use the road distance between two points instead of
> >  > euclidean distance.
> >  >
> >  > I've seen that there is a package named osrm. Can anyone give
> > some advice?
> >
> > I don't know anything about "osrm".  Calculating "road distances"
> > can be
> > done in the spatstat package reasonably easily, if you take the
> trouble
> > to represent your collection of roads as a "linnet" object.
> >
> > Given that you have done so, suppose that your linnet object is "L"
> and
> > that you have vectors "x" and "y" specifying the points on L (i.e. on
> > your roads) between which you want to know the distances.
> >
> > Do:
> >
> >   X<- lpp(data.frame(x=x,y=y),L)
> >   dMat <- pairdist(X)
> >
> > The object "dMat" is a (symmetric) square matrix; dMat[i,j] is the
> > distance between point i and point j.  (Of course the diagonal
> entries
> > are all 0.)
> >
> > If your collection of roads is specified by means of a shapefile,
> > vignette("shapefiles") will tell you how to turn this collection
> into a
> > "psp" ("planar segment pattern") object; the function (method)
> > as.linnet.psp() can then be used to turn the "psp" object into a
> > "linnet" object.
> >
> > HTH
>


-- 
Rol~

[[alternative HTML version deleted]]

___
R-sig-Geo mailing list
R-sig-Geo@r-project.org
https://stat.ethz.ch/mailman/listinfo/r-sig-geo

Re: [R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Rolf Turner]

On 23/06/19 1:17 PM, Rolando Valdez wrote:


Thank you for your answer.

I have a shapefile with, say, counties, and I got another shapefile with 
the roads. ¿What if a county does not intersect any road?


I am sorry, but it is not at all clear to me just what the problem is. 
How do the counties come into the picture?  You said you wanted to get 
the road distance between points on the roads.  What have the counties 
got to do with this?


Can you perhaps provide a reproducible example?

cheers,

Rolf



El jue., 20 de jun. de 2019 a la(s) 19:08, Rolf Turner 
(r.tur...@auckland.ac.nz ) escribió:



On 21/06/19 12:26 PM, Rolando Valdez wrote:

 > Dear community,
 >
 > Is there any way to create a spatial weight matrix based on road
distance?
 > I am trying to use the road distance between two points instead of
 > euclidean distance.
 >
 > I've seen that there is a package named osrm. Can anyone give
some advice?

I don't know anything about "osrm".  Calculating "road distances"
can be
done in the spatstat package reasonably easily, if you take the trouble
to represent your collection of roads as a "linnet" object.

Given that you have done so, suppose that your linnet object is "L" and
that you have vectors "x" and "y" specifying the points on L (i.e. on
your roads) between which you want to know the distances.

Do:

      X    <- lpp(data.frame(x=x,y=y),L)
      dMat <- pairdist(X)

The object "dMat" is a (symmetric) square matrix; dMat[i,j] is the
distance between point i and point j.  (Of course the diagonal entries
are all 0.)

If your collection of roads is specified by means of a shapefile,
vignette("shapefiles") will tell you how to turn this collection into a
"psp" ("planar segment pattern") object; the function (method)
as.linnet.psp() can then be used to turn the "psp" object into a
"linnet" object.

HTH


___
R-sig-Geo mailing list
R-sig-Geo@r-project.org
https://stat.ethz.ch/mailman/listinfo/r-sig-geo

Re: [R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Rolando Valdez]

Thank you for your answer.

I have a shapefile with, say, counties, and I got another shapefile with
the roads. ¿What if a county does not intersect any road?

El jue., 20 de jun. de 2019 a la(s) 19:08, Rolf Turner (
r.tur...@auckland.ac.nz) escribió:

>
> On 21/06/19 12:26 PM, Rolando Valdez wrote:
>
> > Dear community,
> >
> > Is there any way to create a spatial weight matrix based on road
> distance?
> > I am trying to use the road distance between two points instead of
> > euclidean distance.
> >
> > I've seen that there is a package named osrm. Can anyone give some
> advice?
>
> I don't know anything about "osrm".  Calculating "road distances" can be
> done in the spatstat package reasonably easily, if you take the trouble
> to represent your collection of roads as a "linnet" object.
>
> Given that you have done so, suppose that your linnet object is "L" and
> that you have vectors "x" and "y" specifying the points on L (i.e. on
> your roads) between which you want to know the distances.
>
> Do:
>
>  X<- lpp(data.frame(x=x,y=y),L)
>  dMat <- pairdist(X)
>
> The object "dMat" is a (symmetric) square matrix; dMat[i,j] is the
> distance between point i and point j.  (Of course the diagonal entries
> are all 0.)
>
> If your collection of roads is specified by means of a shapefile,
> vignette("shapefiles") will tell you how to turn this collection into a
> "psp" ("planar segment pattern") object; the function (method)
> as.linnet.psp() can then be used to turn the "psp" object into a
> "linnet" object.
>
> HTH
>
> cheers,
>
> Rolf Turner
>
> --
> Honorary Research Fellow
> Department of Statistics
> University of Auckland
> Phone: +64-9-373-7599 ext. 88276
>


-- 
Rol~

[[alternative HTML version deleted]]

___
R-sig-Geo mailing list
R-sig-Geo@r-project.org
https://stat.ethz.ch/mailman/listinfo/r-sig-geo

Re: [R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Andres Diaz Loaiza]

Dear Rolando,

The advantage of using Open Street Maps engine is that you can give the
travel option. This means you can select whether are you traveling by bike,
car or walking. The previous approach didn't consider this topic. For this,
you should have added a vector layer depending on your position of the
street you can take (or not). Open Street Maps project allow you two
options: a service in which you give your current position, the position
you want to reach and your transport method (giving you back the fastest
route). Or the option to download the engine/algorithm compile by yourself
(if I am not wrong is made in C or python) and then you can make your own
calculation at your own computer. For the first option, the package OSRM is
an interface in which send a request to the OSM web page and wait for an
answer. With this method, you can send a couple of request at the same time
but no to many (you should read the manual for this). Of course, also will
depend on whether the OSM server is down or not (or busy).

I have to say that I used some years ago this app and nowadays I know that
for some cities OSM has more streets reported than the same google maps.
Also is an open project and they let you download their data for free,
contrary to what google maps do.

All the best,


Andres

El vie., 21 jun. 2019 a las 4:30, Adrian Baddeley (<
adrian.badde...@curtin.edu.au>) escribió:

> Rather than converting an object of class 'SpatialLines' or
> 'SpatialLinesDataFrame' to the spatstat class 'psp' and then converting it
> to the spatstat class 'linnet', it is safer and more efficient to convert
> the SpatialLines* object directly to class linnet using
> as.linnet.SpatialLinesDataFrame() from the package 'maptools'.
>
>
> Prof Adrian Baddeley DSc FAA
>
> John Curtin Distinguished Professor
>
> Department of Mathematics and Statistics
>
> Curtin University, Perth, Western Australia
>
>
> 
> From: Rolf Turner 
> Sent: Friday, 21 June 2019 10:08 AM
> To: Rolando Valdez
> Cc: r-sig-geo@r-project.org; Adrian Baddeley; Ege Rubak
> Subject: Re: [FORGED] [R-sig-Geo] Create a Spatial Weight Matrix based on
> road distance
>
>
> On 21/06/19 12:26 PM, Rolando Valdez wrote:
>
> > Dear community,
> >
> > Is there any way to create a spatial weight matrix based on road
> distance?
> > I am trying to use the road distance between two points instead of
> > euclidean distance.
> >
> > I've seen that there is a package named osrm. Can anyone give some
> advice?
>
> I don't know anything about "osrm".  Calculating "road distances" can be
> done in the spatstat package reasonably easily, if you take the trouble
> to represent your collection of roads as a "linnet" object.
>
> Given that you have done so, suppose that your linnet object is "L" and
> that you have vectors "x" and "y" specifying the points on L (i.e. on
> your roads) between which you want to know the distances.
>
> Do:
>
>  X<- lpp(data.frame(x=x,y=y),L)
>  dMat <- pairdist(X)
>
> The object "dMat" is a (symmetric) square matrix; dMat[i,j] is the
> distance between point i and point j.  (Of course the diagonal entries
> are all 0.)
>
> If your collection of roads is specified by means of a shapefile,
> vignette("shapefiles") will tell you how to turn this collection into a
> "psp" ("planar segment pattern") object; the function (method)
> as.linnet.psp() can then be used to turn the "psp" object into a
> "linnet" object.
>
> HTH
>
> cheers,
>
> Rolf Turner
>
> --
> Honorary Research Fellow
> Department of Statistics
> University of Auckland
> Phone: +64-9-373-7599 ext. 88276
>
> [[alternative HTML version deleted]]
>
> ___
> R-sig-Geo mailing list
> R-sig-Geo@r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>


-- 
Andrés D.

[[alternative HTML version deleted]]

___
R-sig-Geo mailing list
R-sig-Geo@r-project.org
https://stat.ethz.ch/mailman/listinfo/r-sig-geo

Re: [R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Adrian Baddeley]

Rather than converting an object of class 'SpatialLines' or 
'SpatialLinesDataFrame' to the spatstat class 'psp' and then converting it to 
the spatstat class 'linnet', it is safer and more efficient to convert the 
SpatialLines* object directly to class linnet using 
as.linnet.SpatialLinesDataFrame() from the package 'maptools'.


Prof Adrian Baddeley DSc FAA

John Curtin Distinguished Professor

Department of Mathematics and Statistics

Curtin University, Perth, Western Australia



From: Rolf Turner 
Sent: Friday, 21 June 2019 10:08 AM
To: Rolando Valdez
Cc: r-sig-geo@r-project.org; Adrian Baddeley; Ege Rubak
Subject: Re: [FORGED] [R-sig-Geo] Create a Spatial Weight Matrix based on road 
distance


On 21/06/19 12:26 PM, Rolando Valdez wrote:

> Dear community,
>
> Is there any way to create a spatial weight matrix based on road distance?
> I am trying to use the road distance between two points instead of
> euclidean distance.
>
> I've seen that there is a package named osrm. Can anyone give some advice?

I don't know anything about "osrm".  Calculating "road distances" can be
done in the spatstat package reasonably easily, if you take the trouble
to represent your collection of roads as a "linnet" object.

Given that you have done so, suppose that your linnet object is "L" and
that you have vectors "x" and "y" specifying the points on L (i.e. on
your roads) between which you want to know the distances.

Do:

 X<- lpp(data.frame(x=x,y=y),L)
 dMat <- pairdist(X)

The object "dMat" is a (symmetric) square matrix; dMat[i,j] is the
distance between point i and point j.  (Of course the diagonal entries
are all 0.)

If your collection of roads is specified by means of a shapefile,
vignette("shapefiles") will tell you how to turn this collection into a
"psp" ("planar segment pattern") object; the function (method)
as.linnet.psp() can then be used to turn the "psp" object into a
"linnet" object.

HTH

cheers,

Rolf Turner

--
Honorary Research Fellow
Department of Statistics
University of Auckland
Phone: +64-9-373-7599 ext. 88276

[[alternative HTML version deleted]]

___
R-sig-Geo mailing list
R-sig-Geo@r-project.org
https://stat.ethz.ch/mailman/listinfo/r-sig-geo

Re: [R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Rolf Turner]

On 21/06/19 12:26 PM, Rolando Valdez wrote:


Dear community,

Is there any way to create a spatial weight matrix based on road distance?
I am trying to use the road distance between two points instead of
euclidean distance.

I've seen that there is a package named osrm. Can anyone give some advice?


I don't know anything about "osrm".  Calculating "road distances" can be 
done in the spatstat package reasonably easily, if you take the trouble 
to represent your collection of roads as a "linnet" object.


Given that you have done so, suppose that your linnet object is "L" and 
that you have vectors "x" and "y" specifying the points on L (i.e. on 
your roads) between which you want to know the distances.


Do:

X<- lpp(data.frame(x=x,y=y),L)
dMat <- pairdist(X)

The object "dMat" is a (symmetric) square matrix; dMat[i,j] is the 
distance between point i and point j.  (Of course the diagonal entries 
are all 0.)


If your collection of roads is specified by means of a shapefile, 
vignette("shapefiles") will tell you how to turn this collection into a 
"psp" ("planar segment pattern") object; the function (method) 
as.linnet.psp() can then be used to turn the "psp" object into a 
"linnet" object.


HTH

cheers,

Rolf Turner

--
Honorary Research Fellow
Department of Statistics
University of Auckland
Phone: +64-9-373-7599 ext. 88276

___
R-sig-Geo mailing list
R-sig-Geo@r-project.org
https://stat.ethz.ch/mailman/listinfo/r-sig-geo