Another problem I have is rotating the base map to magnetic north. I
can't seem to find a grass routine that will rotate a raster or a vector
layer. Just rotating the grid would be enough for the base map.
...I'm not using GRASS like one year ago...I'll give it a try...
For rasters:
1- create an imagery group containing the image you need to rotate
2- set the target (i.target) to the location of your source image
3- compute the values for the rotated coordinates externally
4- instead of providing tie points via i.points, go under the
directory of the "group" you created, and create a file called POINTS
in the following format:
# image target status
# east north east north (1=ok)
#
9.648879 43.596939 8.445536 44.476532 1
13.302691 40.549549 9.231250 44.414099 1
9.648879 39.513436 9.186607 44.663829 1
13.607175 37.624054 9.552679 44.351667 1
....
5- i.rectify
...hope this helps (or in the meantime Marcus stuffed in an r.rotate...?)
Cheers,
=========================================
Andrea Giacomelli
Centre for Advanced Studies, Research and
Development in Sardinia
Environment Division
http://www.crs4.it/~andreag
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