[GRASS-user] v.select usage

Rich Shepard rshepard at appl-ecosys.com
Thu Jun 28 09:02:05 PDT 2012


   I want to identify which point features are within each sub-basin and
v.select looks like the appropriate module. However, I must not be using it
properly.

   The example on the manual page has the 'a' map as the points
(firestations) and the 'b' map as the area. When I replicate this with my
data all I see are all the points. For example,

   v.select ain=drillholes bin=catchments out=holesbybasin op=overlap

the resulting map is a duplicate of the drillholes map. Adding the map types
reveals that the 'a' map must be the area since point is not an acceptable
map type in this location. So, I submit,

   v.select ain=catchments atype=area bin=drillholes btype=point \
out=holesbybasin op=overlap

and the resulting map has only the catchments to display and in the
attribute table. Changing the operator in this second attempt to 'contains'
makes no difference to the result: only the catchments and their numbers are
in the output map.

   What I need is a list of point IDs grouped by the catchment number. How do
I use v.select to produce this outcome? Or, is this not the appropriate
module to find the solution to points-in-polygons?

TIA,

Rich



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