On 04/11/08 17:57, Kevin Webb wrote:
Thank you for your reply Hamish.
2 questions based on your suggestion...
At 11:18 PM 10/29/2008, Hamish wrote:
Kevin Webb wrote:
> I am attempting to execute a "point-in-polygon" process on 2 vectors
using
> v.select and the output vector is empty, it contains no value/s.
most likely one of both of the inputs is missing category numbers.
if areas do not have centroids you should add them with v.centroids.
In general add cat numbers to features with v.category.
Your suggestion to use v.category worked, v.select on the output vector
from the
v.category command yielded a result.
1.) Why does a 'cat' column show in both vectors but v.select doesn't
work until
v.category is executed?
Both vectors have the 'cat' column and a visual check of the contents of
the
attribute tables for both vectors show a cat value for all records.
Just because there is a cat column in the attribute table does not mean
that the actual features have category numbers. To check that you can
compare the output of v.category option=report ("count" column) with the
output of v.info -t.
Moritz
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