Color Maps

Color Maps

I’m McKensie Daugherty, your host for on the ocean. Meteorologists on  television often display temperature on a map with reds depicting warm temperatures, going towards blues, which depict cold temperatures, and the other colors between the two. This color gradient from red to blue is known as a color map. Oceanographers typically use a rainbow color map to analyze their data for trends in temperature, salinity, flow fields, and other parameters. Reading these maps can be difficult with the rainbow coloring because it highlights yellow and cyan areas to human eyes. To aid in reducing these arbitrary highlights in data, oceanography researchers developed superior color maps specific to each parameter to minimize interpretation errors. Hypoxia, the lack of oxygen in the water, is one parameter oceanographers study. To show these regions, they highlight oxygen rich areas as yellow and oxygen poor areas as red with grey scale in the middle for areas with normal oxygen levels. All of the newly made color maps are color-blind friendly. And are also translated to better gray scale printing. The new color maps mostly go from dark shades of a color up to light shades of the color, since that is what people are best able to associate with regular changes in data.  Overall using more specific color maps reduces interpretation errors and facilitate better science communication to the public and among scientists. This has been On the Ocean, a program made possible by the Department of Oceanography and a production of KAMU-FM on the campus of Texas A&M University in College Station. For more information and links, please go to ocean.tamu.edu and click On the Ocean.

Contributing Professor: Dr. Kristen Thyng

Contributing Graduate Student/Author: Emily Lewis

 

First figure:

 

The left hand column utilizes specially-designed colormaps for oceanography properties and the right hand column shows the commonly-used but perceptually-challenging jet colormap. Example model output of the sea surface (top row, from Dr. Rob Hetland, Texas A&M) and data from an undulating towed vehicle along the ship track (bottom three rows, from Dr. Steve DiMarco, Texas A&M) are shown. 
 
 Image from:
Thyng, K. M., Hetland, R. D., Zimmerle, H. M., DiMarco, S. F. (in revision). Choosing good colormaps: accurate and effective data visualization. Oceanography.