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.
GRASS 6.4.svn (lat_lon):~ > v.info -c single_point
Displaying column types/names for database connection of layer 1:
INTEGER|cat
CHARACTER|batch_id
DOUBLE PRECISION|decimal_la
DOUBLE PRECISION|decimal_lo
GRASS 6.4.svn (lat_lon):~ > v.info -c PREC0101
Displaying column types/names for database connection of layer 1:
INTEGER|cat
INTEGER|ID
INTEGER|GRIDCODE
CHARACTER|INCHES
2.) How should I copy/transfer the ID|GRIDCODE|INCHES vector table data
from the
source vector to the output vector created by the v.category command?
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