[GRASSLIST:10665] Re: visualise frequency of GPS points in an area

[Dylan Beaudette]

On Wednesday 01 March 2006 06:31 am, Philipp H. Mohr wrote:
> Hello,
>
> I am new to grass and trying to visualise the frequency (density) of
> GPS points in a certain area devided into small cells, therefore in fact
> the amount of GPS points in a cell should be displayed. Looking through the
> manual
> v.neigbors seems the right tool, but I can't get it to work. I am using
> the following settings for my area:
>
> zone:       0
> datum:      wgs84
> ellipsoid:  wgs84
> north:      51:22:54.696N
> south:      51:15:25.452N
> west:       0:51:59.94E
> east:       1:06:48.06E
> nsres:      0:00:00.036
> ewres:      0:00:00.036
> rows:       12479
> cols:       24670
>
> and I load the data in by:
>
> v.in.ascii input=grass.in output=test format=point fs=| x=2 y=1 z=0 cat=0
>
> grass.in can be found here:
>
> http://www.cs.kent.ac.uk/people/rpg/phm4/grass.in
>
>
> Displaying the vector map works with the following command:
> d.vect map=test type=point,line,boundary,centroid,area,face display=shape
> icon=basic/x size=8 layer=1 color=black fcolor=gray llayer=1 lcolor=red
> bgcolor=none bcolor=none lsize=8 font=romans xref=left yref=center
>
>
> But now the trouble starts, when running v.neighbors
>
> v.neighbors input=test output=rasterOut method=count size=0.0001
>
> with varying sizes I don't get any error messages, but when trying to
> display the data with
>
> d.rast map=testRaster
>
> I only get a blank screen.
>
>
> Could some one please tell me which command I need in order to display the
> data. If possible in a 3D landscape.
>
> Thank you very much,
> Phil


I have done something similar to visualize sampling density -- 

http://casoilresource.lawr.ucdavis.edu/drupal/node/172

commands are listed with some sample images.

Cheers,

Dylan

-- 
Dylan Beaudette
Soils and Biogeochemistry Graduate Group
University of California at Davis
530.754.7341