Planning to look at some quantitative colour maps this summer?

TaronishPithawala

University of Washington has analyzed our ability to judge data differences based on different colour scales. Colour scale "viridis" was the winner. Happy Mapping!

https://idl.cs.washington.edu/files/2018-QuantitativeColor-CHI.pdf

Thanks to @NatalieGreen for creating a .tbl version of "viridis" to use in Geosoft's Desktop Applications! Unzip the attached .tbl file into "C:\Program Files\Geosoft\Desktop Applications 9\user\tbl" to see it as a colour ramp in Oasis montaj, Target, and Extensions for ArcGIS.

I've made it the default choice in Oasis montaj - I'll try it out and let you know how I like it.

SaraDeschamps2

Love this, @Taronish!
For more anti-rainbow colour nerding, check out this blog post: https://agilescientific.com/blog/2017/12/14/no-more-rainbows?

TL;DR:
* Instead of rainbows, try to use 'perceptual colourmaps' which are better for interpretation: those that increase linearly and monotonically in brightness, with no jumps or stripes of luminance.
* Choose a colourmap that can be interpreted by viewers with colour blindness, and one that translates well in greyscale (for printing).
* Overlay the image with thin, black, semi-transparent contours that use a small interval.
* Apply hillshading to emphasize depth in the image.

DarrenAndrews

This is great stuff. I think you could hold a lengthy workshop devoted solely to colour mapping for interpretation of geophysical data (as you could for residual isolation in geophysical modelling). Definitely not a case of "one size fits all"!

An important aspect to consider also is not only the colour table itself, but how that colour table is mapped to the data. Geosoft provides a range of different transforms which can be used, don't always accept the "default" settings!

The link Sara quotes above references our friends at the Centre for Exploration (CET) at the University of Western Australia, who have also done a lot of work on colour schemes for interpretation:
(https://peterkovesi.com/projects/colourmaps/)

Included in that link is a series of colour table files for various software, including Geosoft. I've included in this post a zipped folder that contains various CET tbl files for Geosoft. These can be used freely as long as the appropriate credit is given to the CET:

"Peter Kovesi. Good Colour Maps: How to Design Them. arXiv:1509.03700 [cs.GR] 2015"

Below is a comparison of Geosoft default colour table, the Viridis colour table and one of my favourite CET colour tables, "D1" for a TMI dataset from Australia. Each colour table is mapped to the data using a normal transform.