histogram equalized color rules for raster takes inordinately long to display
|Reported by:||isaacullah||Owned by:|
|Keywords:||histogram equalization, display, r.colors||Cc:|
Recently, I have discovered that displaying a map that has been recolored using the histogram equalization option (-e) in r.color takes much much much longer than displaying the same map colored without the histogram equalization option. With a histogram equalized raster, every redisplay takes about 5 minutes, whereas with a normally colored raster, redisplay takes a second. This means that every little action you do that causes a need to redisplay (ie. even just moving the scale bar) leads to a 5 minute wait. I've tested this with 6.4 RC5 and 6.5SVN, and both have the same behavior. I'm using a single ASTER tile as a test raster. The tile displays normally (fast) when given normal color rules, but when the histogram equalization option is checked, it takes about 5 minutes to display it (or even just a small portion of it). I'm using a brand new 64bit core-i5 laptop with 4 gigs of RAM running Ubuntu 10.04. My system is blazing fast, so this is definitely NOT a hardware issue. I don't know if this is a known issue with the -e option of r.color, or perhaps a known issue with installation on Ubuntu 10.04, but I don't remember experiencing this problem in the past (with other versions of 6.4RC's or 6.5SVN on Ubuntu 9.10 or Windows), and I can't find any other open bug tickets that report this problem. If this is indeed a bug, this seems like a pretty major issue that would need to be addressed before the 6.4 stable is released?