On 20/03/08 17:15, Jarek Jasiewicz wrote:
Moritz Lennert wrote:
On 20/03/08 11:17, Jarosław Jasiewicz wrote:
Hi I have lots of raster, thinned lines and second raster with with
one line. I must find all points where second line intersect with
lines on first raster
it is very simple:
r.mapcalc points=if(raster_two==1&&raster_one==1,1,null())
but there is one exception:
AB
BA
when lines intersect with 45 grades. There is intersection but
without common point. Naither buffor nor grow is not a solution
because I need exactly one point lying exactly on line from raster one
Any Ideas
Either ressample your rasters to coarser resolution to make them
coincide, or convert to vector and use a combination of v.patch +
v.clean (e.g. v.clean input=lines1 output=lines2 err=points tool=break)
Moritz
thanks for ansfer
I tried it with similar way (v.patch +v.clean + topology report) but it
is not it. I need EXACT coordinates of pixels on intersection do to
transfer it to another program
The map points (created with the parameter err=points) should contain
exactly these points. Obviously this only works if you can create
correct vector lines from your raster.
See example here:
http://geog-pc40.ulb.ac.be/grass/misc/intersections.html
Moritz
_______________________________________________
grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user
