Universal Palettes & Color Blind Configuration

SeaDAS 7.4 adds a preference page to easily configure the default color schemes for color blind compliance.

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.

* 4th version of the palette (brighter on the red end)

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.

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

The following color palette preferences page governs whether the default palette is color blind compliant. The option determintes whether to use the color-blind compliant palette as the default palette. (see color_palette_schemes.txt located in ~/.seadas/beam-ui/auxdata/color-palettes).