On 13/10/12 15:51, Markus Metz wrote:
In GRASS7, v.distance can now calculate distances from
point,line,boundary,centroid,area to
point,line,boundary,centroid,area.
So how does it calculate the distance between two lines (lines or
boundaries) ? Between closest vertices ? What about lines that cross
several other lines, or lines that cross each other at several points ?
In GRASS 6, v.distance can calculate distances only from
point,centroid to point,line,boundary,centroid,area.
AFAIK, this was due to the conceptual issue mentioned above. I think
that the answer has to be clearly explained in the manual because they
are not as straightforward. And a first rapid test shows that these
issues seem to be problematic in your implementation:
http://164.15.12.207/grass/v_distance_lines.png
http://164.15.12.207/grass/v_distance_areas.png
red: from features (quickly digitized test data available here:
http://164.15.12.207/grass/v_distance_testdata.tgz)
black: to features (roadsmajor and urbanarea from nc_spm_08)
green: connecting lines between from and to feature
Moritz
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