@@ -109,14 +109,15 @@ These would not be good options for use as perceptual colormaps.
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Miscellaneous
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-------------
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- Some of the miscellaneous colormaps have particular uses they have been created
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- for. For example, gist_earth, ocean, and terrain all seem to be created for
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- plotting topography (green/brown) and water depths (blue) together. We would
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- expect to see a divergence in these colormaps, then, but multiple kinks may not
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- be ideal, such as in gist_earth and terrain. CMRmap was created to convert well
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- to grayscale, though it does appear to have some small kinks in :math: `L^*`.
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- cubehelix was created to vary smoothly in both lightness and hue, but appears to
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- have a small hump in the green hue area.
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+ Some of the miscellaneous colormaps have particular uses for which
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+ they have been created. For example, gist_earth, ocean, and terrain
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+ all seem to be created for plotting topography (green/brown) and water
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+ depths (blue) together. We would expect to see a divergence in these
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+ colormaps, then, but multiple kinks may not be ideal, such as in
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+ gist_earth and terrain. CMRmap was created to convert well to
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+ grayscale, though it does appear to have some small kinks in
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+ :math: `L^*`. cubehelix was created to vary smoothly in both lightness
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+ and hue, but appears to have a small hump in the green hue area.
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The often-used jet colormap is included in this set of colormaps. We can see
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that the :math: `L^*` values vary widely throughout the colormap, making it a
@@ -141,17 +142,18 @@ might be better (see effort on this front at [mycarta-cubelaw]_).
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Grayscale conversion
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====================
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- Conversion to grayscale is important to pay attention to for printing
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- publications that have color plots. If this is not paid attention to ahead of
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- time, your readers may end up with indecipherable plots because the grayscale
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- changes unpredictably through the colormap.
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+ It is important to pay attention to conversion to grayscale for color
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+ plots, since they may be printed on black and white printers. If not
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+ carefully considered, your readers may end up with indecipherable
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+ plots because the grayscale changes unpredictably through the
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+ colormap.
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Conversion to grayscale is done in many different ways [bw ]_. Some of the better
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ones use a linear combination of the rgb values of a pixel, but weighted
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according to how we perceive color intensity. A nonlinear method of conversion
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to grayscale is to use the :math: `L^*` values of the pixels. In general, similar
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principles apply for this question as they do for presenting one's information
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- perceptually; that is, if a colormap is chosen that has monotonically increasing
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+ perceptually; that is, if a colormap is chosen that is monotonically increasing
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in :math: `L^*` values, it will print in a reasonable manner to grayscale.
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With this in mind, we see that the Sequential colormaps have reasonable
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