site.to.vector.to.rast

GRASS GRASS user
1

I would like to build a raster layer from valued site data after using the
s.voronoi option in geom to generate polygons around each site. So far,
my approach has been to:

1) create an ASCII site file with category values and labels.
2) use s.in.ascii to convert it to a GRASS site list.
3) apply the voronoi tesselation in geom to the site list to produce
    the vector layer.

Now, how can I produce a raster layer that assigns a site's value to all of
the cells contained within that site's polygon?

Thanks in advance for your help,

Cliff Behrens

2

Cliff

Here is what I did.

  1. v.support
  2. v.digit - close polygons by breaking lines and snapping in the
                     edit menu, and then labelling the areas.
  3. v.to.rast
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Richard Beecham email:beecham@aerg.canberra.edu.au
Hydrology Unit phone:(02) 895 7169
NSW Department of Water Resources fax :(02) 895 7834
Parramatta NSW 2124
Australia

On Mon, 6 Jun 1994, Cliff Behrens wrote:

I would like to build a raster layer from valued site data after using the
s.voronoi option in geom to generate polygons around each site. So far,
my approach has been to:

1) create an ASCII site file with category values and labels.
2) use s.in.ascii to convert it to a GRASS site list.
3) apply the voronoi tesselation in geom to the site list to produce
    the vector layer.

Now, how can I produce a raster layer that assigns a site's value to all of
the cells contained within that site's polygon?

Thanks in advance for your help,

Cliff Behrens

3

On Mon, 6 Jun 1994, Cliff Behrens wrote:

Now, how can I produce a raster layer that assigns a site's value to all of
the cells contained within that site's polygon?

Thanks in advance for your help,

If you have true polygons, ie areas, the site list can be fairly easily
converted to a list of area labels. Have a look at existing files in the
$LOCATION/dig_att directory for the proper format. If the polygons are
not true areas, you would need to do some editing - I can supply further
details if necessary. Once the dig and dig_att files are OK you can run
v.support and v.to.rast on the map.

P. Martijn van Leusen
Institute of Prehistory, University of Amsterdam
martijn@scanner.frw.uva.nl