[GRASS-user] How to categorize my areas
mlennert at club.worldonline.be
Tue Dec 15 00:15:52 PST 2015
On 15/12/15 00:22, Martin Landa wrote:
> 2015-12-15 0:18 GMT+01:00 Alec Ventura <alecventura at hotmail.com>:
>> I run the v.buffer with the -t flag and everything is ok now
> I wonder if attributes should be copied by default (without need to
> set up any flag).
v.buffer fusions the geometries of buffers by default. Keeping the
attribute table does not make sens in that case as one buffer geometry
can be the result of many different input geometries. This also means
that you cannot retrieve the buffer of a specific input geometry.
When you use the -t flag, buffers are cut up into separate parts and
each one that is the result of several overlapping buffers has multiple
categories. As the man page says: "The resulting buffer areas can have
multiple categories, and multiple buffer areas can have the same
category. The buffer for the input feature with category X can thus be
retrieved by selecting all buffer areas with category X".
Keeping in mind GRASS' topological vector format the current behavior
seems the most adequate to me.
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