Michael Hearne wrote: > Ryan - Thanks for your response. > > Shouldn't a color dictionary have 4 "columns" - a value, and the > corresponding R,G,B values? If I understand your response, the "row" > with 0.2 as the first column has only two values. How does > LinearSegmentedColormap derive an RGB triplet from those two numbers? >
Not quite. I'm pretty sure I was a little vague in my last message, so let me be more concrete. Here's an example of a 5 gray level color map data dictionary: _Gray5_data = {'blue': [(0.0, 0.42352941176470588, 0.42352941176470588), (0.25, 0.53333333333333333, 0.53333333333333333), (0.5, 0.6588235294117647, 0.6588235294117647), (0.75, 0.81568627450980391, 0.81568627450980391), (1.0, 0.93725490196078431, 0.93725490196078431)], 'green': [(0.0, 0.42352941176470588, 0.42352941176470588), (0.25, 0.53333333333333333, 0.53333333333333333), (0.5, 0.6588235294117647, 0.6588235294117647), (0.75, 0.81568627450980391, 0.81568627450980391), (1.0, 0.93725490196078431, 0.93725490196078431)], 'red': [(0.0, 0.42352941176470588, 0.42352941176470588), (0.25, 0.53333333333333333, 0.53333333333333333), (0.5, 0.6588235294117647, 0.6588235294117647), (0.75, 0.81568627450980391, 0.81568627450980391), (1.0, 0.93725490196078431, 0.93725490196078431)]} Note that the dictionary contains one list each for red, green, and blue. Each entry in the a list for the color corresponds to an entry in the table. This entry has 3 pieces of information: The first (item #1) is the corresponding normalized data value for this color (between 0 and 1). The next two values are normalized color values, the first if the actual data value is below the value in item #1 and the 2nd if it is above. In the case of the one above, the color is the same regardless. So, for example, a normalized data value of 0.25 gets an RGB tuple of (0.5333,0.5333,0.5333). HTH, Ryan -- Ryan May Graduate Research Assistant School of Meteorology University of Oklahoma ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users