Michael Barton wrote: > Currently, if you use the -a flag with g.region it will align the > region exactly to match the resolution of a map (e.g. g.region -a > rast=myrast will set the region to exactly the resolution of myrast > regardless of the extents) or the resolution specified in the res or > ewres/nwres fields (e.g. g.region -a n=523 s=15 res=10 will adjust > the extents a little to make sure the resolution is exactly 10). > > However, -a is ignored if the map argument (rast=) or resolution > arguments are blank.
Actually, you need either vect= or res= (or nsres= or ewres=). rast= doesn't have any effect. Also, the interpretation is different for vect= compared to the resolution options. > This means that if you want to change the > extents and keep your current resolution, you need to specify the -a > flag AND explicitly specify the resolution. Otherwise, the resolution > will be adjusted slightly. > > Could this be modified so that when the -a flag is used and > resolution is NOT specified and a map is NOT specified (i.e., only > changing extents) it aligns to the current resolution? That is, > respect the -a flag when res/ewres/nsres= is blank and rast= is blank. It would be possible to implement the -a flag unconditionally, although you would need to exclude the cases which already have a defined meaning (e.g. "g.region -a nsres=..." only aligns the top and bottom edges, leaving the left and right edges unchanged). -- Glynn Clements <[EMAIL PROTECTED]> _______________________________________________ grass-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-dev
