On Mar 4, 2008, at 1:08 PM, Moritz Lennert wrote:
On Tue, March 4, 2008 18:04, John C. Tull wrote:
I think your approach with two runs is adequate, although I am not
sure which tool you would use to extend your polygon as I have not
looked into that issue recently. I have similar questions that I
address. In order to get names of the polygons (conservation areas
for
you), I go beyond v.select to populate a field with the names of the
areas being queried. I then dump to a text file that I can open in a
spreadsheet application for summarizing. My example assumes you
have a
field called 'name' in your input polygon file:
v.select ainput=in_points binput=conservation_polygons
out=points_in_polygons
v.db.addcol points_in_polygons col="polygon_name VARCHAR(40)"
v.distance from= points_in_polygons to=conservation_polygons dmax=0
upload=to_attr to_column=name col=polygon_name
v.db.select points_in_polygons > points_in_polygons.txt
Just out of curiosity: do you really need the v.select ? Wouldn't
this work:
v.db.addcol in_points col="polygon_name VARCHAR(40)"
v.distance from=in_points to=conservation_polygons dmax=0 /
upload=to_attr to_column=name col=polygon_name
?
Moritz
I suppose you might be able to do that. I used the v.select to first
subsample a larger dataset to create a file of points that fall within
the polygons. Your approach would append polygon_name to the entire
points file, which may be perfectly suitable for some peoples needs.
Unless I am missing something, a definite possibility.
John
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