Hi again, I'm still struggling with how to add the attribute values from a polygon map to the table for a point map. I've tried v.what.vect, as documented in my previous message. Any suggestions would be appreciated!
Thanks, Tyler On March 14, 2014 2:29:49 PM EDT, Tyler Smith <[email protected]> wrote: >Hello, > >I have a vector point map, amelanchier, and a vector polygon map, >hwSoil. I tried to extract data from hwSoil for each point in >amelanchier as follows: > >v.db.addcol map=amelanchier columns="T_GRAVEL double precision" >v.what.vect vector=amelanchier qvector=hwSoil qcolumn=T_GRAVEL \ >column=T_GRAVEL > >I've repeated this process for a few dozen columns. > >However, I'm not getting the right values. If I investigate a single >point using d.what.vect, notice that the values for T_GRAVEL in >amelanchier is not the same as that in hwSoil. I've included some of >the other columns that also show small discrepancies. > >d.what.vect -t > >82:13:46.5625W(E) 36:23:46.875N(N) > > hwSoil in PERMANENT Area >Size - Sq Meters: 10269585820.955 Hectares: 1026958.582 > Acres: 2537669.922 Sq Miles: 3965.1093 >Layer: 1 >category: 4608 >driver: sqlite >database: /home/tws/grassdata/hwSoilsDB/PERMANENT/sqlite.db >table: hwsdData >key column: MU_GLOBAL >ADD_PROP : 0 >T_GRAVEL : 10 >T_SAND : 49 >T_SILT : 27 >T_CLAY : 24 >T_USDA_TEX_CLASS : 10 >T_REF_BULK_DENSITY : 1.4 >T_BULK_DENSITY : 1.4 > >amelanchier in PERMANENT Point >Layer: 1 >category: 668 >driver: sqlite >database: /home/tws/grassdata/hwSoilsDB/PERMANENT/sqlite.db >table: amelanchier >key column: cat >cat : 668 >accession : 10-217 >species : ARB >country : USA >state : TN >y : 36.3966 >x : -82.22792 >ADD_PROP : 0 >T_GRAVEL : 11 >T_SAND : 44 >T_SILT : 33 >T_CLAY : 23 >T_USDA_TEX_CLASS : 9 >T_REF_BULK_DENSITY : 1.39 >T_BULK_DENSITY : 1.35 > >What have I done wrong here? Is v.what.vect doing some kind of >interpolation? I've attached a small section of my map, so you can see >that the individual points are placed within large polygons, so I >don't think there's a chance that I'm clicking in a different polygon >than the one the point is in. > >Thanks for your help! > >Tyler > > >------------------------------------------------------------------------ > >_______________________________________________ >grass-user mailing list >[email protected] >http://lists.osgeo.org/mailman/listinfo/grass-user _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
