On Fri, May 27, 2011 at 10:53:58AM -0600, John Abraham wrote:
> create or replace view dot_cnt as
> select the_geom, polygon_id, (quantity_column/100)::integer as numpoints
> from original_data;
>
> select dot_density('dot_cnt',
> 'the_geom',
> 'polygon_id',
> 'numpoints');
>
> alter table
Just to follow up on this, here is the code we (Abdel-Rahman M. Muhsen and I)
finally got around to writing. We found a function called randompoint which
just creates random points within the bounding box of the geometry from
Alexandre Sorokine.
http://sorokine.blogspot.com/2011/05/postgis-fun
ay, May 06, 2010 8:56 AM
To: John Abraham; postgis-users@postgis.refractions.net; Martin
Davis
Subject: Re: [postgis-users] Dot Density idea
I was thinking the same thing!
strk wrote:
ST_RandomPoinsOnSurface(geometry, numpoints) would be an interesting
function indeed. Sounds like
erate_series(1,1000) as point_number) as
>>>>>> rand1
>>>>>> JOIN (select random() as rand, generate_series(1,1000) as
>>>>>> point_number)
>>>>>> as
>>>>>> rand2
>>>>>> ON rand1.point_nu
m,
>>>>>>>> st_makeline(
>>>>>>>> st_pointn(st_exteriorring(the_geom),
>>>>>>>> (rand1.rand *
>>>>>>>> st_npoints(st_exteriorring(the_geom)))::int),
>>>>>&
ay 06, 2010 8:56 AM
To: John Abraham; postgis-users@postgis.refractions.net; Martin Davis
Subject: Re: [postgis-users] Dot Density idea
I was thinking the same thing!
strk wrote:
ST_RandomPoinsOnSurface(geometry, numpoints) would be an interesting
function indeed. Sounds lik
as point_number)
>>>>>> as
>>>>>> rand2
>>>>>> ON rand1.point_number = rand2.point_number
>>>>>> JOIN (select random() as rand, generate_series(1,1000) as point_number)
>>>>>&
.net
[mailto:postgis-users-boun...@postgis.refractions.net] On
Behalf Of Martin Davis
Sent: Thursday, May 06, 2010 8:56 AM
To: John Abraham; postgis-users@postgis.refractions.net; Martin
Davis
Subject: Re: [postgis-users] Dot Density idea
I was thinking the same thing!
strk wrote:
gis.refractions.net; Martin Davis
Subject: Re: [postgis-users] Dot Density idea
I was thinking the same thing!
strk wrote:
ST_RandomPoinsOnSurface(geometry, numpoints) would be an interesting
function indeed. Sounds like a good job for GEOS/JTS.
--strk;
On Mon, May 03, 2010 at 10:
iorring(the_geom), (rand1.rand *
> st_npoints(st_exteriorring(the_geom)))::int),
> st_pointn(st_exteriorring(the_geom), (rand2.rand *
> st_npoints(st_exteriorring(the_geom)))::int)
> )
> )
> ) = 'ST_LineString'
> AND oid = 5030 /* Enter your own OID here */
On Fri, 5/7/10, Martin Davis wrote:
> From: Martin Davis
> Subject: Re: [postgis-users] Dot Density idea
> To: "PostGIS Users Discussion"
> Date: Friday, May 7, 2010, 5:50 AM
> Did your algorithm work with
> irregular polgon extents?
>
> Jan Hartmann wrote:
&
Yea, this is very cool indeed.
George
On Thu, May 6, 2010 at 3:33 PM, David Fawcett wrote:
> Doesn't OpenSource suck!!!
>
>
> On Mon, May 3, 2010 at 11:49 PM, John Abraham
> wrote:
> > One of the things I miss about using ESRI's GIS is the ability to do
> dot-density maps. Within a polygon, th
Doesn't OpenSource suck!!!
On Mon, May 3, 2010 at 11:49 PM, John Abraham wrote:
> One of the things I miss about using ESRI's GIS is the ability to do
> dot-density maps. Within a polygon, the number of dots is
An then an hour later...
http://lin-ear-th-inking.blogspot.com/2010/05/random-poi
Behalf Of Martin Davis
Sent: Thursday, May 06, 2010 8:56 AM
To: John Abraham;
postgis-users@postgis.refractions.net
<mailto:postgis-users@postgis.refractions.net>;
r) as
>>>>>> rand1
>>>>>> JOIN (select random() as rand, generate_series(1,1000) as
>>>>>> point_number)
>>>>>> as
>>>>>> rand2
>>>>>> ON rand1.point_number = rand2.point_number
>>&
avis
Sent: Thursday, May 06, 2010 8:56 AM
To: John Abraham; postgis-users@postgis.refractions.net; Martin
Davis
Subject: Re: [postgis-users] Dot Density idea
I was thinking the same thing!
strk wrote:
ST_RandomPoinsOnSurface(geometry, numpoints) would be an
interesting
function in
own OID here */
limit 100
-Original Message-
From: postgis-users-boun...@postgis.refractions.net
[mailto:postgis-users-boun...@postgis.refractions.net] On
Behalf Of Martin Davis
Sent: Thursday, May 06, 2010 8:56 AM
To: John Abraham; postgis-users@postgis.refractions.net; Martin Davis
Subjec
s.net; Martin Davis
Subject: Re: [postgis-users] Dot Density idea
I was thinking the same thing!
strk wrote:
ST_RandomPoinsOnSurface(geometry, numpoints) would be an interesting
function indeed. Sounds like a good job for GEOS/JTS.
--strk;
On Mon, May 03, 2010 at 10:49:32PM -0600, Jo
st_pointn(st_exteriorring(the_geom), (rand1.rand *
>>> st_npoints(st_exteriorring(the_geom)))::int),
>>> st_pointn(st_exteriorring(the_geom), (rand2.rand *
>>> st_npoints(st_exteriorring(the_geom)))::int)
>>> )
>>&g
st_npoints(st_exteriorring(the_geom)))::int)
>>> )
>>> )
>>> ) = 'ST_LineString'
>>> AND oid = 5030 /* Enter your own OID here */
>>> limit 100
>>>
>>>
>>>
>>>
>>>
>>>> -Orig
Message-
From: postgis-users-boun...@postgis.refractions.net
[mailto:postgis-users-boun...@postgis.refractions.net] On
Behalf Of Martin Davis
Sent: Thursday, May 06, 2010 8:56 AM
To: John Abraham; postgis-users@postgis.refractions.net; Martin Davis
Subject: Re: [postgis-users] Dot Density idea
I w
ions.net
> >[mailto:postgis-users-boun...@postgis.refractions.net] On
> >Behalf Of Martin Davis
> >Sent: Thursday, May 06, 2010 8:56 AM
> >To: John Abraham; postgis-users@postgis.refractions.net; Martin Davis
> >Subject: Re: [postgis-users] Dot Density idea
> &g
gt;To: John Abraham; postgis-users@postgis.refractions.net; Martin Davis
>Subject: Re: [postgis-users] Dot Density idea
>
>
>I was thinking the same thing!
>
>strk wrote:
>> ST_RandomPoinsOnSurface(geometry, numpoints) would be an interesting
>> function indeed. Sounds lik
I was thinking the same thing!
strk wrote:
ST_RandomPoinsOnSurface(geometry, numpoints) would be an interesting
function indeed. Sounds like a good job for GEOS/JTS.
--strk;
On Mon, May 03, 2010 at 10:49:32PM -0600, John Abraham wrote:
One of the things I miss about using ESRI's GIS is the
I have used an R function before (using maptools package) to do something
similar, but I can't remember the details, so I would be considering looking at
PL/R.
cheers
Ben
On 06/05/2010, at 15:40 , strk wrote:
> On Mon, May 03, 2010 at 10:49:32PM -0600, John Abraham wrote:
>> One of the thin
Not quite the same, but Carson Farmer's fTools plugins for QGIS
include the functionality to create random points (by count or
density) inside of a polygon.
http://www.ftools.ca/plugins.html Nothing specific about this
functionality on this page, you need to look at the actual plugins in
QGIS.
D
ST_RandomPoinsOnSurface(geometry, numpoints) would be an interesting
function indeed. Sounds like a good job for GEOS/JTS.
--strk;
On Mon, May 03, 2010 at 10:49:32PM -0600, John Abraham wrote:
> One of the things I miss about using ESRI's GIS is the ability to do
> dot-density maps. Within a po
On Mon, May 03, 2010 at 10:49:32PM -0600, John Abraham wrote:
> One of the things I miss about using ESRI's GIS is the ability to do
> dot-density maps. Within a polygon, the number of dots is proportional to a
> value, and the dots are randomly placed. I find it useful to be able to
> present
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