[GRASS-user] r.colors

[Markus Neteler]

On Thu, Oct 22, 2015 at 1:47 PM, Paul Shapley <p.shapley at gmail.com> wrote:
> Hi All,
>
> Just testing 7.0.2RC1 with some landsat 8 images. I've imported and changed
> the DN values to TOAR values but when i try to use a 'Histogram Stretch'
> using the 'grey' table the maps display no color (white display) whereas in
> version 6 it worked.

Is the computational region the same?

> Also i need to increase the 'contrast' when displaying
> the individual bands but dont know if there is a way to do this.

You may try
https://grass.osgeo.org/grass70/manuals/i.colors.enhance.html

> I have tried opening the 'i.fusion.hpf' script but it seems to hang.

Which operating system do you use? And with "hanging" you mean that
the GUI does not come up or that it makes no progress (CPU load high
or low?). This may again suggest that the computational region is not
right, say, that there are too many active pixels.

just some ideas what to look for,
Markus