[GRASS-user] limit Voronoi or other vector programs

[William L. Baker]

Yes, that would be useful too.

Yes, in the case of vector points, a MASK-like function would be 
conceptually simpler than dealing with vector lines and polygons.

v.voronoi produces lots of spurious polygons if there is lots of space 
without points outside where the points actually lie, which occurs if a 
study area has an irregular shape (not rectangular). Thus, some kind of 
buffer around the points is needed to set limits on the analysis space. 
I think someone is revising this program, and perhaps this problem can 
be addressed, but it may not be easy to program. A more general MASK 
solution would be useful for all point-based programs.

Bill B.

Wolf Bergenheim wrote:
> Another thing (which I'd like to see in GRASS 7.0) would be to have a
> where parameter for all v. modules which would allow one to filter the
> points based on the attributes (usually this is enough)
>
> --Wolf
>
> On 01.10.2008 21:03, Maris Nartiss wrote:
>   
>> Hello,
>> currently there is no MASK support for vector data. Only solution is
>> to extract a subset of whole dataset into new vector map/layer with
>> existing GRASS tools (i.e. v.extract and others).
>>
>> Also MASK concept for vector data is easy to implement for vector
>> points but it gets tricky with lines/areas. What should happen to
>> line/area that crosses MASK border?
>> Also as MASK normally is applied "on fly", it could be real show
>> stopper when working with large datasets (i.e. LiDAR data).
>>
>> WBR,
>> Maris.
>>
>> 2008/10/1 William L. Baker <bakerwl at uwyo.edu>:
>>     
>>> Hello,
>>> It would be useful to be able to use something similar to r.mask to be able
>>> to limit the area that v.voronoi (or other programs) use. Is there a way to
>>> mask out particular areas?
>>>
>>> Bill B.
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>