[AstroPy] DS9 color tables in Python

[John Zuhone]

So I'm able to do it in yt, which is probably just a short step from doing
it in AstroPy, since it's just NumPy and Matplotlib calls:

http://nbviewer.ipython.org/gist/jzuhone/3472085f67e41f20e00f

CIAO (Chandra software) contains all of the ds9 colormaps, so I extracted
"sls.lut" from there and just read it in.

Does anyone know if there are any licensing issues with the ds9 colormaps?

Tom, where would something like this go in astropy.visualization?

On Tue, Mar 31, 2015 at 9:36 AM, John Zuhone <jzuhone at gmail.com> wrote:

> It's definitely do-able, I did it for a couple of ds9 colormaps by hand
> for yt, actually. I can try seeing if I can script it up.
>
> On Tue, Mar 31, 2015 at 9:01 AM, Peter Teuben <teuben at astro.umd.edu>
> wrote:
>
>> On 03/31/2015 08:25 AM, Thomas Robitaille wrote:
>> > On 31 March 2015 at 14:00, Peter Weilbacher <pweilbacher at aip.de> wrote:
>> >> Dear all,
>> >>
>> >> has anyone succeeded to set up DS9-like color tables for plotting in
>> >> Python? I'm specifically interested in "heat", "sls", "hsv", and "b".
>> >>
>> >> I know that matplotlib defines somewhat similar tables, but e.g.
>> >> "gist_heat" is just too different from DS9's (and skycat's) heat...
>> > If this doesn't exist, this might be a good addition to
>> > astropy.visualization or pyds9!
>> >
>> > Tom
>>
>>
>> Since I had done something similar in a long ago past, I had a quick peek
>> at the source distro of ds9.   I was surprised to see this part documented
>> very lightly (if at all), but the "obvious" code to look at is in
>>     saods9/saotk/colorbar/default.C
>> where a series of
>>
>>   red.append(new LIColor(0,0));
>>   red.append(new LIColor(1,1));
>>
>>   green.append(new LIColor(0,0));
>>   green.append(new LIColor(1,1));
>>
>>   blue.append(new LIColor(0,0));
>>   blue.append(new LIColor(1,1));
>>
>> create a colortable.   The SLS color scheme, which happens to
>> be my favorite, does this in RGB space:
>>
>>   colors.append(new RGBColor(0.000000, 0.000000, 0.000000));
>>   colors.append(new RGBColor(0.043442, 0.000000, 0.052883));
>>   colors.append(new RGBColor(0.086883, 0.000000, 0.105767));
>>   colors.append(new RGBColor(0.130325, 0.000000, 0.158650));
>> ...
>>   colors.append(new RGBColor(1.000000, 1.000000, 1.000000));
>>   colors.append(new RGBColor(1.000000, 1.000000, 1.000000));
>>   colors.append(new RGBColor(1.000000, 1.000000, 1.000000));
>>
>> others are done programmatically (check out HSV )
>>
>> I NEMO and GIPSY these live as ascii tables with 256 entries of RGB
>> scaled 0..1, and I checked a few and the ds9 ones seem to match
>> the ones I see in GIPSY or NEMO. (NEMO/data/lut or GIPSY/dat/lut)
>>
>> The ds9 codebase also has some yacc & lex parsing, i'm not clear
>> if that's still used. Clearly the distribution doesn't contain these
>> LUT ascii type files. If we're interested in persuing this, we should
>> check with Bill Joye about the best approach to scrape it the right
>> way.
>>
>> My old notes from 2003 tell me that ds9 can read my LUT/RGB ascii tables,
>> but I cannot find this in the current ds9 (7.3.x)
>> http://carma.astro.umd.edu/nemo/man_html/lut.5.html
>>
>> peter
>>
>>
>>
>>
>>
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>>
>
>
>
> --
> John ZuHone
>
> Postdoctoral Researcher
> NASA/Goddard Space Flight Center
>
> jzuhone at gmail.com
> john.zuhone at nasa.gov
>



-- 
John ZuHone

Postdoctoral Researcher
NASA/Goddard Space Flight Center

jzuhone at gmail.com
john.zuhone at nasa.gov
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