Hi Paul,
What you could do is create a template palette file with colour decided by values (RGB_Mapping By_value) and write a small script which takes the upper/lower bounds you want and fills them in. The substitution command can be issued via the spawn command.
Say we have dummy_template.spk
------------
RGB_Mapping By_value
! Red/White/Blue template
LO 100 0 0
-0.001 100 100 100
0.001 100 100 100
HI 0 0 100
------------
A little bit of sed...
yes? sp "sed -s 's/LO/-2/;s/HI/5/' <dummy_template.spk > red_white_blue.spk"
yes? sp cat red_white_blue.spk
RGB_Mapping By_value
! Red/White/Blue template
-2 100 0 0
-0.001 100 100 100
0.001 100 100 100
5 0 0 100
In general you can use symbols to make this clearer
yes? def sym loval = -2
yes? def sym hival = 5
yes? sp "sed -s 's/LO/($loval)/;s/HI/($hival)/' <dummy_template.spk > red_white_blue.spk"
Even better put the spawn command and symbol definitions into a ferret script along with a few other commands and it can even adjust the middle values or you can adjust multiple levels of a palette and all you'll ever need to do is issue a command like
go make_rwb_palette -2 5
Cheers,
Russ
On 20/11/14 04:45, Paul Goddard wrote:
Hello all,
I would like to have a color scale that is divergent (such as blue_darkred.spk) where the near zero-values are light and get darker the further from zero in each direction. However, I would like the, say red (positive) values to go to 4, but the blue (negative) values to only go to -2. Therefore, the zero is not the centered number on the scale, though the colors diverge from it as if it were. I hope to be able to do this to show the changes in the negative values with a darker shade. Is this possible without creating new *.spk scales for every graph?
Thanks in advance,
Paul
--
Paul GoddardPhD Candidate
Department of GeosciencesUniversity of Arizona