>>>>> Hamish <[EMAIL PROTECTED]> writes: >>> an idea: write a little script to make a vector coversheet index.
[...] >>> I am not sure, but I think v.patch does not clean topology so >>> overlap may be ok. > Ivan: >> Wouldn't it be better to save non-overlapping parts and an >> intersection as separate polygons? A separate attribute will be >> needed to store the list of IDs of the covering images. > see overlapping polygon example at: > http://grass.ibiblio.org/screenshots/vector.php Thanks, I'll check it. >>> # store current region >>> g.region save=old_region >> It makes me wonder each time I see such a fragile construct like >> this, will GRASS ever support overriding the region >> ``temporarily''? (E. g., via a command line argument, or an >> environment variable.) > there is, see GRASS_REGION and WIND_OVERRIDE shell variables: > http://grass.ibiblio.org/grass63/manuals/html63_user/variables.html This is exactly what I've asked for. Thanks! > but saving & restoring g.region isn't need for this task, it is just > being nice leaving the place as you found it. The script is not > dependent on the starting region. And I fail to see how that's > fragile? Consider this script being interrupted in the middle (say, by the user hitting ^C.) Will the region be restored? > No more fragile than trusting anything else written to the disk. It looks to me that the following will be much more robust: export WIND_OVERRIDE=tmp_region ... # no need to store current region # g.region save=old_region ... g.region rast="$MAP" ... # no need to reset to original region, either # g.region old_region [...] >> And, could there be something a bit more clever than storing the >> region of the image as a vector feature? > the user can get as complicated as they like.. >> A combination of downsampling, `r.mapcalc' (to obtain the fill mask), >> and `r.contour', may be? > r.contour is not so good for ortho photos or high resolution land use > map with many small areas. But again, up to the user.... Actually, I meant using `r.contour' on the downsampled fill mask. (Meanwhile, I've silently switched to my own needs, which are about the satellite data.) [...] _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
