|
NAMEv.select - Selects features from vector map (A) by features from other vector map (B).KEYWORDSvector, geometry, spatial querySYNOPSISv.selectv.select --help v.select [-tcr] ainput=name [alayer=string] [atype=string[,string,...]] binput=name [blayer=string] [btype=string[,string,...]] output=name operator=string [relate=string] [--overwrite] [--help] [--verbose] [--quiet] [--ui] Flags:
Parameters:
DESCRIPTIONv.select allows the user to select features from a vector map by features from another one.Supported operators (without GEOS; using GRASS’ own algorithm):
NOTESOnly 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.EXAMPLESPreparation of example data (North Carolina sample dataset):# Create an grid for overlaying to ZIP code vector map v.mkgrid map=boxgrid grid=10,10 position=coor \ coordinates=583600,201500 box=5000,5000 # set region to ZIP codes and boxgrid vector maps g.region vector=zipcodes_wake,boxgrid -p res=100 -a # enlarge region a bit for "white border" around map in monitor g.region n=n+1000 s=s-1000 w=w-1000 e=e+1000 -p d.mon wx0 OVERLAP: features partially or completely overlap (using GRASS)Select grid boxes (North Carolina sample dataset):d.vect map=zipcodes_wake fill_color=0:128:0 d.vect map=boxgrid fill_color=85:130:176 v.select ainput=boxgrid binput=zipcodes_wake output=v_select_OVERLAP operator=overlap d.vect map=v_select_OVERLAP d.vect map=zipcodes_wake type=boundary color=255:255:50 v.select with OVERLAP operator: selected grid boxes shown in yellow (using GRASS method) OVERLAPS features spatially overlap (using GEOS)Select grid boxes (North Carolina sample dataset):d.vect map=zipcodes_wake fill_color=0:128:0 d.vect map=boxgrid fill_color=85:130:176 v.select ainput=boxgrid binput=zipcodes_wake output=v_select_OVERLAPS operator=overlaps d.vect map=v_select_OVERLAPS d.vect map=zipcodes_wake type=boundary color=255:255:50 v.select with OVERLAPS operator: selected grid boxes shown in yellow (using GEOS method) DISJOINT: features do not spatially intersect (using GEOS)Select grid boxes (North Carolina sample dataset):d.vect map=zipcodes_wake fill_color=0:128:0 d.vect map=boxgrid fill_color=85:130:176 v.select ainput=boxgrid binput=zipcodes_wake output=v_select_DISJOINT operator=disjoint d.vect map=v_select_DISJOINT d.vect map=zipcodes_wake type=boundary color=255:255:50 v.select with DISJOINT operator: selected grid boxes shown in yellow EQUALS: features are spatially equals (using GEOS)Select zipcode polygon (North Carolina sample dataset):d.vect map=zipcodes_wake fill_color=0:128:0 v.extract input=zipcodes_wake where=ZIPCODE_ID=35 output=zipcodeID35 v.select ainput=zipcodes_wake binput=zipcodeID35 output=v_select_EQUALS operator=equals d.vect map=v_select_EQUALS d.vect map=zipcodes_wake type=boundary color=255:255:50 v.select with EQUALS operator: selected grid boxes shown in yellow INTERSECTS: features spatially intersect (using GEOS)Select zipcode polygons (North Carolina sample dataset):d.vect map=zipcodes_wake fill_color=0:128:0 d.vect map=boxgrid fill_color=85:130:176 v.select ainput=zipcodes_wake binput=boxgrid output=v_select_INTERSECTS operator=intersects d.vect map=v_select_INTERSECTS d.vect map=boxgrid type=boundary color=255:255:50 v.select with INTERSECTS operator: selected grid boxes shown in yellow TOUCHES: features spatially touches (using GEOS)Select polygons (North Carolina sample dataset):d.vect map=zipcodes_wake fill_color=0:128:0 d.vect map=zipcodeID35 fill_color=85:130:176 v.select ainput=zipcodes_wake binput=zipcodeID35 output=v_select_TOUCHES operator=touches d.vect map=v_select_TOUCHES d.vect map=zipcodes_wake type=boundary color=255:255:50 v.select with TOUCHES operator: selected polygons shown in yellow (blue: input polygon) CROSSES: features spatially crosses (using GEOS)Select zipcode polygons by lines (North Carolina sample dataset):d.vect map=zipcodes_wake fill_color=0:128:0 d.vect map=busroute1 color=200:27:27 width=3 v.select ainput=zipcodes_wake binput=busroute1 output=v_select_CROSSES operator=crosses d.vect map=v_select_CROSSES d.vect map=zipcodes_wake type=boundary color=255:255:50 d.vect map=busroute1 color=200:27:27 width=3 v.select with CROSSES operator: selected polygons shown in yellow (red: input lines) WITHIN feature A is completely inside feature B (using GEOS)Select zipcode polygons (North Carolina sample dataset):d.vect map=zipcodes_wake fill_color=0:128:0 d.vect map=boundary_county fill_color=85:130:176 v.select ainput=zipcodes_wake binput=boundary_county output=v_select_WITHIN operator=within d.vect map=v_select_WITHIN v.select with WITHIN operator: selected polygons shown in yellow (blue: input polygons) CONTAINS feature B is completely inside feature A (using GEOS)Select zipcode polygon (North Carolina sample dataset):CONTAINS with polygonsd.vect map=zipcodes_wake fill_color=0:128:0 d.vect map=zipcodeID35 fill_color=85:130:176 v.select ainput=zipcodes_wake binput=zipcodeID35 \ output=v_select_CONTAINS_pol operator=contains d.vect map=v_select_CONTAINS v.select with CONTAINS operator: selected polygon shown in yellow (blue: input polygon, not visible) CONTAINS with pointsd.vect map=zipcodes_wake fill_color=0:128:0 d.vect map=hospitals fill_color=195:31:31 icon=basic/cross3 size=10 v.select ainput=zipcodes_wake binput=hospitals \ output=v_select_CONTAINS_pnts operator=contains d.vect map=v_select_CONTAINS_pnts d.vect map=hospitals fill_color=195:31:31 icon=basic/cross3 size=10 v.select with CONTAINS operator: selected polygons shown in yellow (red: input points) RELATE feature A is spatially related to feature B (using GEOS)This operator additionally requires the relate parameter (in other GIS called ’ST_Relate’). This operator allows calculating the Dimensionally Extended nine-Intersection Model (DE-9IM). In the following one example: Select polygon with ’TOUCHES’ operator (North Carolina sample dataset):d.vect map=zipcodes_wake fill_color=0:128:0 d.vect map=zipcodeID35 fill_color=85:130:176 v.select ainput=zipcodeID35 binput=zipcodes_wake \ output=v_select_TOUCHES_relate operator=relate relate=’T********’ d.vect map=v_select_TOUCHESThe result of relate=’T********’ is the same as seen above in the example ’TOUCHES’. See the DE-9IM page for related operators and their definition. Extraction of points falling into a polygonExtract fire stations (points) falling into urban area (polygon) - North Carolina data set (point in polygon test):v.select ainput=firestations binput=urbanarea output=urban_firestations \ operator=overlap Extraction of lines overlapping with a polygonExtract railroad lines from zip code map overlapping with the urban area (line in polygon test):v.select ainput=railroads binput=urbanarea \ output=railroads_in_urbanarea operator=overlap Extraction of areas overlapping with a lineExtract those areas from zip code map which overlap with railroads (polygon on line test):# first add a tiny buffer around railroad lines: v.buffer input=railroads output=railroads_buf20m \ distance=20 v.select ainput=zipcodes_wake binput=railroads_buf20m \ output=zipcodes_wake_railroads operator=overlap SEE ALSOv.category, v.clip, v.overlay, v.extractGRASS SQL interface
AUTHORSRadim BlazekGEOS support by Martin Landa, Czech Technical University in Prague, Czech Republic ZIP code examples by Carol X. Garzon-Lopez, Trento, Italy SOURCE CODEAvailable at: v.select source code (history)Main index | Vector index | Topics index | Keywords index | Graphical index | Full index © 2003-2021 GRASS Development Team, GRASS GIS 7.8.6 Reference Manual
Visit the GSP FreeBSD Man Page Interface. |