[GRASS-user] Determining number of overlapping features per location after import of shape file

[Rainer M Krug]

Hi

I am importing a vector layer from a shape file as follow, and get the
warning below:

> v.in.ogr  dsn=/home/rkrug/Documents/Projects/AlienSpread/data/input/ layer=fireHistory output=fireHistory --overwrite


WARNING: 703 areas represent more (overlapping) features, because polygons
         overlap in input layer(s). Such areas are linked to more than 1
         row in attribute table. The number of features for those areas is
         stored as category in layer 2


I am aware of that, and I want to create a raster layer with the
number of features overlapping in each location. As I ultimately need
a raster layer, I thought to use the following, but I get the error
message below:

> v.to.rast  input=fireHistory layer=2 output=mf use=attr column=category --overwrite

ERROR: Unable to get layer info for vector map

Why is that?

Is there another way of getting the number of overlapping features per cell?

Thanks

Rainer


-- 
Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation
Biology, UCT), Dipl. Phys. (Germany)

Plant Conservation Unit
Department of Botany
University of Cape Town
Rondebosch 7701
South Africa