other versions
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- testing 7.6.0-1
- unstable 7.6.0-1
- experimental 7.6.1-1~exp1
v.select(1grass) | Grass User's Manual | v.select(1grass) |
NAME¶
v.select - Selects features from vector map (A) by features from other vector map (B).KEYWORDS¶
vector, spatial querySYNOPSIS¶
v.selectFlags:¶
- -t
-
- -c
-
- -r
-
- --overwrite
-
- --verbose
-
- --quiet
-
Parameters:¶
- ainput=name
-
- atype=string[,string,...]
-
- alayer=integer
-
- binput=name
-
- btype=string[,string,...]
-
- blayer=integer
-
- output=name
-
- operator=string
-
- relate=string
-
DESCRIPTION¶
v.select allows the user to select features from a vector map by features from another one. Supported operators (without GEOS):- overlap - features partially or completely overlap
- equals - features are spatially equals
- disjoint - features do not spatially intersect
- intersects - features spatially intersect
- touches - features spatially touches
- crosses - features spatially crosses
- within - feature A is completely inside feature B
- contains - feature B is completely inside feature A
- overlaps - features spatially overlap
- relate - feature A is spatially related to feature B
NOTES¶
Only features with category numbers will be considered. If required the v.category module can be used to add them. Typically boundaries do not need to be given a category number, as an area's attributes are inherited from the centroid. Typically points, lines, and centroids will always want to have a cat number. E.g. take a road which separates two farms. It is ambiguous as to which farm an attribute that is attached to the road belongs to. The boundary only needs a cat number if it will hold its own attributes, such as road name or pavement form. A centroid in each paddock holds the information with respect to ownership, area, etc.EXAMPLES¶
Extract fire stations (points) from urban area map (polygon) - North Carolina data set:operator=overlap
output=watrcrsl_italy operator=overlap
TODO¶
Processing areas with GEOS is currently incredibly slow. Significant speed-up is required.SEE ALSO¶
v.category, v.overlay, v.extract GRASS SQL interfaceAUTHORS¶
Radim BlazekGRASS 6.4.4 |