Pablo Romero wrote: > Eric, > > I believe the problem is that my 19 levels are not evenly distributed; > > Lv=(1,3,5,6,7,8,9,10,12,14,16,18,20,25,30,35,40,50,75)
No, I don't think that has much to do with it, unless the problem is that the colors of some levels are too similar. Again, please make a simple, complete, self-contained example, and we will go from there. I think what you want may be something like this: levs=[1,3,5,6,7,8,9,10,12,14,16,18,20,25,30,35,40,50,75] norm = mpl.colors.BoundaryNorm(levs, 256) z = rand(10,15)*14 # fake data covering only lower levs contourf(z, levs, norm=norm, cmap=cm.jet, extend='both') colorbar() > > the first part of the range starts at 1,3,5, but then includes 6,7,8,9, and > then only goes with even numbers..10,12,14,16,18,20...then by 5 up until 35, > then jumps by 10...etc. > > I know this seems strange, but this was done because Im plotting 'ocean wave > heights' and these were decided to be the 'heights of interest' for the > project Im working on. > Perfectly reasonable. > anyway, what I want is to be able to breakup the 'cm.jet' spectrum evenly > based on the # of levels (and not on their values), and spread my levels > evenly across the spectrum.... > > i.e., I want the first 6-7 levels to be evenly spread from blue to about > green acros cm.jet's spectrum, approx. the next 6 levels to be evenly spread > across cm.jet's yellow-orange part of the spectrum, and the last few levels > to be evenly spread across the reds... > > Ideally, Id like to be able to use any colormap, and simply break up its > color spectrum evenly, and then assign each distinct color to each level in > my levels array. > > So, I guess I need a method to programatically, evenly break up cm.jet by the > # of levels, create a colors array & pass this array to > contourf(colors='mycolorsarray')... > > does this make sense? > > P.Romero > > ---------------------------------------- >> Date: Sun, 15 Mar 2009 08:32:32 -1000 >> From: efir...@hawaii.edu >> Subject: Re: [Matplotlib-users] question about levels & colormaps for >> contour functions >> To: romero...@hotmail.com >> CC: matplotlib-users@lists.sourceforge.net >> >> Pablo Romero wrote: >>> Hi, >>> >>> I would like to know how I can pass an array of levels and also a colormap >>> to the contour() function and have the levels span the entire colormap. >>> example... >>> >>> if I do the following.... >>> >>> >>> Lv=(1,3,5,6,7,8,9,10,12,14,16,18,20,25,30,35,40,50,75) >>> >>> cs=plt.contourf(X,Y,waveheight,Lv,cmap=cm.jet,extend='both') >>> >>> >>> I would expect that contours that are in the higher levels (i.e., levels >>> above value '14' in my levels array) would be plotted with lighter colors >>> in the cm.jet spectrum; the greens, yellows,oranges,reds, etc. >>> >>> However, contourf is simply breaking up the lower,"dark blue" half of the >>> cm.jet spectrum into small slices, and spreading all of my levels >>> throughout only the bottom half of cm.jet. >>> >> I don't see the problem yet. Here is an attempt to recreate what it >> sounds like you are describing above (run in ipython -pylab): >> >> contourf(rand(10,12), arange(0,5.01,0.2), cmap=cm.jet, extend='both') >> colorbar() >> >> The data are all blue because they are in the 0-1 range, while the >> levels span the 0-5 range. The colorbar shows that the colormap is >> covering the latter range, as it should. >> >> If you can make a simple self-contained example like this, and then >> describe the difference between what it does and what you want it to do, >> we can figure out how to get your desired result. >> >> Eric >> >> >> >> >> >>> I followed this tutorial: >>> http://www.scipy.org/Cookbook/Matplotlib/ColormapTransformations >>> >>> that shows how to create a "discrete" colormap, but this also didnt work; >>> the contourf function again simply sliced up the lower, blue colors and >>> spread my all of my layers across the "blues" in my discrete colormap. >>> >>> >>> If I use a colors array instead of a colormap, I can achieve what I want. >>> However, Id like to be able to use a colormap so that I dont have to >>> manually create color arrays everytime that I want to change my colorscheme. >>> >>> So, how can I force contour() to spread my levels across THE WHOLE spectrum >>> of a colormap? >>> >>> Please help, >>> >>> Thanks, >>> P.Romero >>> >>> >>> _________________________________________________________________ >>> Express your personality in color! 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