[GRASS-user] vector point density

Hello!
I'm working with terrestrial laser scanning data and have built up a DEM of a Gully system with IDW. Now, I would like to know the density of points in each cell!

How can I get this?

Thanks for hints!
Manuel

--

_______________________________________________________________________
Dr. Manuel Seeger
Wiss. Assistent Scientific Assistant
Physische Geographie Dpt. of Physical Geography
FB VI - Geographie/Geowissenschaften Geography/Geosciences
Universität Trier University of Trier
D - 54286 Trier
Tel.: +49-651-201 4557
Fax: +49-651-201 3976
Web: http://www-neu.uni-trier.de/index.php?id=9607

On Wednesday 24 October 2007, Dr. Manuel Seeger wrote:

Hello!
I'm working with terrestrial laser scanning data and have built up a DEM
of a Gully system with IDW. Now, I would like to know the density of
points in each cell!

How can I get this?

Thanks for hints!
Manuel

Couple ways to do this.

1. v.kernel ... but this counts up points within a gaussian (?) kernel
2. r.in.xyz method=n on the original data
3. v.mkgrid + v.select ?

4. use the grid from above example, import into PostGIS along with points.
perform intersection and aggregate based on grid cell, counting the number of
points which are associated with.

cheers,

Dylan

--
Dylan Beaudette
Soil Resource Laboratory
http://casoilresource.lawr.ucdavis.edu/
University of California at Davis
530.754.7341

Dr. Manuel Seeger wrote:

I'm working with terrestrial laser scanning data and have built up a DEM
of a Gully system with IDW. Now, I would like to know the density of
points in each cell!

How can I get this?

r.in.xyz method=n

here is an example pic of point density/raster cell for LIDAR data:
  http://hamish.bowman.googlepages.com/grassfiles#xyz
  (click image to enlarge)

you can run r.univar on the "n" map result to gets stats on average density,
etc.

Hamish

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