Comments on: Updated Brewer color tables http://michaelgalloy.com/2008/02/21/updated-brewer-color-tables.html Resources for IDL developers Sun, 23 Nov 2008 09:20:11 +0000 http://wordpress.org/?v=2.6.2 By: michaelgalloy.com » Brewer color table fixes http://michaelgalloy.com/2008/02/21/updated-brewer-color-tables.html#comment-67900 michaelgalloy.com » Brewer color table fixes Thu, 22 May 2008 22:05:09 +0000 http://michaelgalloy.com/2008/02/21/updated-brewer-color-tables.html#comment-67900 [...] made some fixes to the Brewer color tables addressing the issues reported in the comments of the last update by Philippe Le Sage. The update includes the [...] [...] made some fixes to the Brewer color tables addressing the issues reported in the comments of the last update by Philippe Le Sage. The update includes the [...]

]]> By: Philippe http://michaelgalloy.com/2008/02/21/updated-brewer-color-tables.html#comment-58637 Philippe Wed, 23 Apr 2008 20:57:04 +0000 http://michaelgalloy.com/2008/02/21/updated-brewer-color-tables.html#comment-58637 By plotting R,G and B vectors, I found that the diverging tables are centered on 117. First half is index 0-116 and second half is 117-233. They basically saturate after index 233. So I just load the 256 colors and use only the first 233 colors. By plotting R,G and B vectors, I found that the diverging tables are centered on 117. First half is index 0-116 and second half is 117-233. They basically saturate after index 233.

So I just load the 256 colors and use only the first 233 colors.

]]> By: Michael Galloy http://michaelgalloy.com/2008/02/21/updated-brewer-color-tables.html#comment-57517 Michael Galloy Sun, 20 Apr 2008 04:19:33 +0000 http://michaelgalloy.com/2008/02/21/updated-brewer-color-tables.html#comment-57517 I'll take a look at that. My most recent version has different values for the qualitative color tables since it seemed silly to have a separate color table for each number of colors (since the 7 color version is exactly the same first 6 colors in the color table). It also didn't seem worthwhile to interpolate them to take up all 256 indices, now they just use the actual needed indices. I’ll take a look at that.

My most recent version has different values for the qualitative color tables since it seemed silly to have a separate color table for each number of colors (since the 7 color version is exactly the same first 6 colors in the color table). It also didn’t seem worthwhile to interpolate them to take up all 256 indices, now they just use the actual needed indices.

]]> By: Philippe Le Sager http://michaelgalloy.com/2008/02/21/updated-brewer-color-tables.html#comment-57315 Philippe Le Sager Sat, 19 Apr 2008 13:47:36 +0000 http://michaelgalloy.com/2008/02/21/updated-brewer-color-tables.html#comment-57315 Thanks a lot for those. I have thought using those color tables since I saw the Brewer article in EOS, but never implemented more than one in my IDL codes. I have a little concern about the interpolation to 256 colors you used to produce the tbl file. The diverging color tables seem a little bit off-center: you expect to have a clear neutral middle color (even though not in the table itself), but in the RdBu for example the 121-127 indices seem to be on the "blue side". No too much of an issue when loading very few or a lot of colors, but may bother some users loading 20-40 colors? IDL> loadct, 22, file=file_which('brewer.tbl') % LOADCT: Loading table RdBu(Diverging) IDL> cindex IDL> loadct, 22, file=file_which('brewer.tbl'), ncolo=16 % LOADCT: Loading table RdBu(Diverging) IDL> cindex IDL> loadct, 22, file=file_which('brewer.tbl'), ncolo=64 % LOADCT: Loading table RdBu(Diverging) IDL> cindex Thanks a lot for those. I have thought using those color tables since I saw the Brewer article in EOS, but never implemented more than one in my IDL codes.

I have a little concern about the interpolation to 256 colors you used to produce the tbl file. The diverging color tables seem a little bit off-center:
you expect to have a clear neutral middle color (even though not in the table itself), but in the RdBu for example the 121-127 indices seem to be on the “blue side”.
No too much of an issue when loading very few or a lot of colors, but may bother some users loading 20-40 colors?

IDL> loadct, 22, file=file_which(’brewer.tbl’)
% LOADCT: Loading table RdBu(Diverging)
IDL> cindex
IDL> loadct, 22, file=file_which(’brewer.tbl’), ncolo=16
% LOADCT: Loading table RdBu(Diverging)
IDL> cindex
IDL> loadct, 22, file=file_which(’brewer.tbl’), ncolo=64
% LOADCT: Loading table RdBu(Diverging)
IDL> cindex

]]> By: michaelgalloy.com » ColorBrewer http://michaelgalloy.com/2008/02/21/updated-brewer-color-tables.html#comment-46993 michaelgalloy.com » ColorBrewer Thu, 21 Feb 2008 17:22:51 +0000 http://michaelgalloy.com/2008/02/21/updated-brewer-color-tables.html#comment-46993 [...] I updated the color tables to fix problems with the qualitative color tables and added new routines to access [...] [...] I updated the color tables to fix problems with the qualitative color tables and added new routines to access [...]

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