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

Rainer M Krug r.m.krug at gmail.com
Mon Jun 23 06:13:48 EDT 2008


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?



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

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