Dear list,
I am working with spatstat and am trying to define my owin: spatial region
(observation window). I have a set of marked planar point patterns generated
from random samplings in different strata. Unfortunately I don't have any
GIS file with all the information for each of my strata. I
Aurelie,
If all you need is defining the region, perhaps the easiest is
guessing the coordinates from the
grid of your jpg file.
Alternatively, you can georeference the jpg to make a companion world
file that would let you use
your map as an spatial object. You can use qgis for that.
Agus
Hi!
Given a Sp Points DF and an Sp Polygons DF, I want to add a field of
number of points for each polygon
to the Sp Pol. DF table. This is what I'm doing (using objects from
the help page for sp::overlay()
(meuse is the Sp Points DF and srdf the Sp Pol. DF)
delme3 - overlay(meuse,srdf)
delme3
Hi Aurelie,
You should tell us more about your data to help you efficiently.
What (database, etc) are you sampling?
what are the different strata?
how are the random samples selected?
Cheers,
Marcelino
At 15:36 18/10/2011, GodinA wrote:
Dear list,
I am working with spatstat and am
Hi,
The latter method seems good to me. I haven't found any other alternative
for this purpose.
2011/10/18 Agustin Lobo alobolis...@gmail.com
Hi!
Given a Sp Points DF and an Sp Polygons DF, I want to add a field of
number of points for each polygon
to the Sp Pol. DF table. This is what I'm
Marcelino,
My dataset is coming from annual bottom-trawl surveys in waters off
Newfoundland and Labrador Region, Canada. I am looking at habitat selection
(relationship to depth temperature), geographic distribution, and
abundance of skate species in the region in 2009.
The survey use a
Thank you Agus, I'll look at qgis.
-
Aurelie Cosandey-Godin
Ph.D. Student, Department of Biology, Dalhousie University
Industrial Graduate Fellow, WWF-Canada
Email: god...@dal.ca | Web: wormlab.biology.dal.ca
--
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Actually, neither alternative works if there are polygons with no
points, as those
are not kept in the output of overlay and just binding tp the table of
srdf is not possible.
The second alternative looks easier for a join, but a problems comes
from the fact that
the output data.frame of
delme4 -
Agus,
Have you looked into over, which is supposed to replace overlay?
require(sp)
vignette(over)
On 10/18/2011 05:06 PM, Agustin Lobo wrote:
Actually, neither alternative works if there are polygons with no
points, as those
are not kept in the output of overlay and just binding tp the table
Aurelie,
with this information, I'm afraid that your data cannot be considered
as marked point partterns because your points are not the result
of a stochastic point process but instead are selected (although
hazaphartdly) for sampling pourposes. Others may correct me but I
would find
Hummm...
Thank you Marcelino, I agree with you, this dataset isn't a clear stochastic
point process per se, however I'm wondering if I can still treat it as such,
acknowledging the limitations. Would love hearing people comments.
I will look at the dismo package.
On a slightly different note,
I'm afraid I do not understand well the help page.
It seems to me that what I need is
x = SpatialPointsDataFrame, y = SpatialPolygons
equal to the previous method, except that an argument fn=xxx is
allowed, e.g. fn = mean which will then report a data.frame with the
mean values of the x points
Hi,
There is an easy way to do this, but it is outside R. I use GME (geospatial
modelling environment). It can also run R commands however.
The function in that program you are looking for is: countpntsinpolys
More information on: http://www.spatialecology.com/gme/gmecommands.htm
Best,
Mieke
sorry for the offlist reply...
with the use of qgis, here is a similar problem (georeferencing image) found
on the qgis user forum.
there are several messages in this thread. hopefully you will find some
direction here.
http://lists.osgeo.org/pipermail/qgis-user/2011-October/013911.html
On Tue,
Thank you Brad! Will definitely look into this Qgis mailing list!
Cheers, ~Aurelie
-
Aurelie Cosandey-Godin
Ph.D. Student, Department of Biology, Dalhousie University
Industrial Graduate Fellow, WWF-Canada
Email: god...@dal.ca | Web: wormlab.biology.dal.ca
--
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Dear all,
I try to use GWR analysis in spgwr package. Some data for depedent variable is
missing in this polygon dataset. I have tried to use SAR or CAR method and they
works well. But when I use GWR in spgwr package, I got an error message,
new data matrix rows mismatch
This is because GWR in
I am trying to calculating 95th percentile within polygons from a of
set realizations - something like zonal statistics.
How do I calculate 95 th percentile for each polygon over all realizations.
Thanks
Zia
For example:
data(meuse)
data(meuse.grid)
coordinates(meuse) - ~x+y
Zia,
You may want to rethink the question. Each realization has a 95
percentile within a particular polygon. Over the set of realizations of
some aggregated value for a polygon, you can take a 95 percentile.
These are two different things. The first is a spatial aggregation, the
second an
Your are correct. Now, what I am going to do: first calculate 95th
percentile of all realizations at prediction grid and then calculate
the mean for each polygon. Is it possible to calculated weighted mean
of the this 95th percentile? weight may be area of polygon or any
value, for
Hi Mathieu,
I'm not sure why RStudio is crashing on you with that input, on my apple laptop
with R 2.13.2 I get the following error when I run your sample code:
Error in RGEOSBinTopoFunc(spgeom1, spgeom2, byid, id, rgeos_intersection) :
TopologyException: no outgoing dirEdge found at 898287
On 10/18/2011 11:45 PM, Zia Ahmed wrote:
Your are correct. Now, what I am going to do: first calculate 95th
percentile of all realizations at prediction grid and then calculate the
mean for each polygon.
this implies you end up with one single value per polygon. Call it A.
Is it possible
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