I am trying to do a spatial join in GRASS 5.7 and am stuck.
I am creating a file of vector areas from polylines using v.type, and a file of vector points that represent the centroids of those areas. I'd like to join the two vector maps such that the cat value of each point in the point file becomes the cat value (or at least A value) of the corresponding area in the vector area file. I assume that the vector 'areas' will actually be boundaries lacking centroids after I create them in v.type.
I know how I would do it in GRASS 5.3, as well as in ArcView and MapInfo. I have a feeling that it is possible to do this in GRASS 5.7, but can't figure out which command to use and how to do it. Thanks.
Michael
____________________
C. Michael Barton, Professor
School of Human Origins, Cultures, & Societies
PO Box 872402
Arizona State University
Tempe, AZ 85287-2402
USA
Phone: 480-965-6262
Fax: 480-965-7671
www: <www.public.asu.edu/~cmbarton>
On Thursday 10 June 2004 07:33, Michael Barton wrote:
I am trying to do a spatial join in GRASS 5.7 and am stuck.
I am creating a file of vector areas from polylines using v.type, and a
file of vector points that represent the centroids of those areas. I'd
like to join the two vector maps such that the cat value of each point
in the point file becomes the cat value (or at least A value) of the
corresponding area in the vector area file. I assume that the vector
'areas' will actually be boundaries lacking centroids after I create
them in v.type.
I know how I would do it in GRASS 5.3, as well as in ArcView and
MapInfo. I have a feeling that it is possible to do this in GRASS 5.7,
but can't figure out which command to use and how to do it. Thanks.
Say that you have 2 inputs: 'lines', 'points'
v.patch input=lines,points output=areas1
v.type input=areas1 output=areas2 type=line,boundary,point,centroid
It may be that your lines are closed polygons, in that case you have to run also
v.clean input=areas2 output=areas3 tool=bpol,rmdupl,break,rmdupl
Radim