Universal Palettes & Color Blind Configuration

The Universal Palette


Image 1. The Universal Palette


The above image depicts the SeaDAS Universal Palette (file=universal_bluered.cpd) which is a color-blind compliant palette. This palette was designed to optimize and maximize the number of colors being used to ensure an optimum dynamic range while maintaining compliance with the 3 primary color blindness types. The idea here is to have a palette which transitions smoothly and evenly from left to right (low to high). The palette purposely avoids the use of grayscale colors, so that these can be used for land, nodata, cloud, and other mask diplays.



The 3 images which follow show simulations of how the color palette would look to various types of color blind people. This palette passes all simulations with the goal of smooth and even transitions being maintained and no repetitions of colors.



Image 2. Universal Palette (Deuteranope Simulation)



Image 3. Universal Palette (Protanope Simulation)



Image 4. Universal Palette (Tritanope Simulation)


The following images illustrates the intensities of the red, green, and blue channels for this palette. Of primary note is that the blue channel tracks essentially inversely to the other two channels. The variance of the red and green channels at times helps to bring out color variations for the non-color blind person, while for the color-blind person the "yellow" channel (average of red and green) essentially continues to track smoothly. To support protanope compliance the right-side of the palette goes to red.


Image 5a. RGB value plot of universal palette



Image 5b. RGB intensity plot of universal palette



Image 6. MODIS Aqua Chlorophyll Scene (using universal palette)




The Rainbow Palette



Image 7. Rainbow Palette

The above image depicts a palette which emulates the solar spectrum (for instance the colors of the rainbow). This palette has problems when viewed by color blind people as can be seen in the follwing simulation images.


Image 8. Rainbow Palette (Deuteranope Simulation)



Image 9. Rainbow Palette (Protanope Simulation)



Image 10. Rainbow Palette (Tritanope Simulation)


A linear plot shown below illustrates this tracking problem associated with the "yellow" channel.


Image 11a. RGB value plot of rainbow palette



Image 11b. RGB intensity plot of rainbow palette



Image 12. MODIS Aqua Chlorophyll Scene (using rainbow palette)






The Anomalies Universal Palettes


Additionally SeaDAS provides 2 color blind compliant anomalies palettes which are essentially derived from the SeaDAS Standard Universal. These are: file=anomalies1_universal.cpd and file=anomalies2_universal.cpd.


Image 13. SeaDAS Anomalies1 ("Soft") Universal Pallete




Image 14. SeaDAS Anomalies2 ("Hard") Universal Pallete




Image 5a. RGB value plot of anomalies1 palette



Image 5b. RGB intensity plot of anomalies1 palette




How to Configure For Color Blind Compliancy

SeaDAS can be configured to use the universal (color blind compliant) palette by default. To do this open the Preferences Window (on Mac: Menu > SeaDAS > Preferences > Color Manager) (on Windows/Linux: Menu > Tools > Options > Color Manager).

set: Scheme (default) Palette = "UNIVERSAL"

set: Scheme (Band Lookup) Palette = "From Scheme UNIVERSAL"

Note: Palettes (Default) UNIVERSAL: this is the "universal palette" key which is set by default to "universal_bluered.cpd"