Colormaps Constructed with an Artist in the Loop
Working with COSIM climate modelers at LANL artist Francesca Samsel and the Data Science at Scale Team, LANL developed colormaps that enable scientists to see more detail within their simulations. The colormaps move through changes in hue, saturation and value to create a longer line through colorspace. The maps have been user tested for their ability to show even and accurate detail. Here are a few of the user study “winners” to be added.
On a practical note, the colormaps draw a longer line through color space by independently specified H, S, and V values. Some maps have 20 control points, others over 40. Removing some control points, as long as you are adjusting in LAB space, is fine, but you will lose some of the detailed color contrast which is what makes these maps effective.
A special thanks to James Ahrens, Data Science at Scale, LANL, for leading the way and to Greg Abram, TACC, UT Austin, for the tools to translate color theory into pixels. This material is based upon work supported by Lucy Nowell, Computer Scientist and Program Manager, Advanced Scientific Computing Research, Office of Science, U.S. Department of Energy. Award Numbers: DE- SC-0012516 and LA-UR-15-20105.
Contact for Francesca: figs@cat.utexas.edu
THE COLORMAPS….. that made the cut
Extended Cool / Warm – This colormap moves through a wider range of hue and saturation than current standards. Useful if you are looking for a greater level of detail.
Hue-Extended Warm Cool – This map conatins more contrast within the context of a cool warm format via extended hue ranges. It is a favorite of climate modelers.
Linear YGB – moving throught intuition hue transitions and value
A key principle from the design community, “Less is more.”
Muted Blue Green A quieter option.
Asymmetry
The asymmetrical maps were first developed to take advantage of the larger perceptual range within the green spectrum. They quickly became popular for their ability to show a greater level of detail, especially when combined with the reverse function in the colormap editor. Below is a temperature visualization of the POP ocean model from the COSIM team at Los Alamos National Laboratory. It has the additional value of highlighting the Gulf Stream.
Green Blue Asymmetrical Divergent
Asymmetrical Earth Tones
Linear Colormaps
Green 917 – A linear colormaps that moves through saturation and hue shifts to create greater contrast.
Yellow 15 – moving through hue and value.
Blue 831- turqoise green to navy blue
It’s so great to see what an artist can do, these reveal amazing detail.
These will be really useful in highlighting subtle changes in variables e.g curvatures. Are there any plans to add them into VTK? It would be nice to see these as a class in VTK much like vtkNamedColors. Maybe it could be called vtkNamedColorMaps.
Ken Moreland also did some work on diverging color spaces: https://www.google.com.au/url?sa=t&source=web&rct=j&ei=0VhUVanGC4Ti8AX-0oLACw&url=http://www.sandia.gov/~kmorel/documents/ColorMaps/ColorMapsExpanded.pdf&ved=0CB4QFjAA&usg=AFQjCNHtuNoldmiHVU54-MsIXaokuqr0-w&sig2=F-3Wd_Mxn7H2La_hTDkwug
@Andrew, that’s an excellent idea. No, we hadn’t thought of making these accessible in VTK. BTW, I know that Francesca, who’s the author of this post and did most of the work represented here, is/was indeed aware of Ken’s previous work.
These are really promising color maps! It would be cool to have them in a ParaView importable format or even ship them with ParaView!
@Lars, these are indeed included in the ParaView nightly binaries and will be available in the next release of ParaView.