[GRASS-user] Slow display of images (rasters)

[Hamish]

Morten Sickel wrote:

> I am working with some aerial photograps, I have sets of pancromatic black
> and white pictures and colored infrared pictures. the pan-images were
> imported directly and displays quite qickly, each image being about 150M.
> When I imported the colored IR pictures, they came in as three bands, each
> about the same size as the pancromatic picture. Then I used r.composite to
> recreate the colored picture, and got a file on about 500M. When I use d.rast
> to display the composite file, things takes ages, nothing seems to happen for
> a long while. d.rast uses more or less 100% of the CPU but not much memory. I
> recall the xdriver being slow when displaying rasters with a large color
> space as an issue some years ago, but I thought that worked better now.. Are
> there anything I can do to make it work better? I have presently 24 bits
> color depth, but that is going to increase to 36 bits (3x12bits) later on, if
> that goes even slower, I will have a problem...


1) check "g.region -p"  If rows & columns is much greater than 10000x10000 you
might want to consider using a more coarse resolution. Check r.info for the
images too.

2) Try d.rgb instead of r.composite.


Hamish


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