[GRASS-user] v.what.rast for lines

[Jitendra Kumar]

Hi,
"v.what.rast" allows to extract the values from the raster at the vector
points. How to do a similar operation for a vector map consisting of lines
instead of points. I have road network as vector and I wish to extract the
average value over each line segment from a raster.

I thought of several options but had one or other conceptual problem. I can
convert the vector line to points using "v.to.points" and extract the values
at each point using "v.what.rast". But I am not sure how to identify the
points lying on a particular line in order calculate the average over the
line.
I do want to preserve the lines in my road network vector data since it gets
used in some other network analysis as well.

If I have several attributes associated with my raster, how to specify the
attribute to be extracted to "v.what.rast" ?

I am quite confused as to how to do this. Any pointers would be of great
help?

Thanks,
Jitu
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/grass-user/attachments/20091208/35c4f5ee/attachment.html