[GRASS-dev] problem with r.colors on Mac

[Maciej Sieczka]

Glynn Clements wrote:

> Done; r.colors now has -e (hist. eq.) and -g (log. scale) options.

Glynn,

Wow! Now GRASS is able to equalize any color table, superb. Thank you.

Messing around with the new feature I found there is a difference
between -e/-g color=grey and the old color=grey.eq/grey.log; in spearfish:

$ r.colors landcover.30m col=grey.eq
$ r.mapcalc 'tryit_old_eq=#landcover.30m'

$ r.colors -e landcover.30m col=grey
$ r.mapcalc 'tryit_new_eq=#landcover.30m'

There is a difference between the 2 colortables it seems:

$ r.mapcalc 'dif_eq=tryit_new_eq-tryit_old_eq'
$ r.info -r dif_eq
min=-1
max=0

In case of logarithmic scaling there is a difference too:

$ r.colors landcover.30m col=grey.log
$ r.mapcalc 'tryit_old_log=#landcover.30m'

$ r.colors -g landcover.30m col=grey
$ r.mapcalc 'tryit_new_log=#landcover.30m'

$ r.mapcalc 'dif_log=tryit_new_log-tryit_old_log'
$ r.info -r dif_log
min=0
max=10

Is that as expected?

Maciek