Welcome to MyCarta!

Hi everyone and welcome. As I mention in the blog header and in my about page, this is Matteo Niccoli’s blog of Topics in Geophysics, Planetary Exploration, Image Processing, Digital […]

Logarithmic spiral, nautilus, and rainbow

The other day I stumbled into an interesting article on The Guardian online: The medieval bishop who helped to unweave the rainbow. In the article I learned for the first time of Robert […]

Convert Matlab colormap to Surfer colormap

In the comment section of my last post, Steve asked if I had code to generate a Surfer.clr file from my Matlab colormaps. Some time ago I did write a […]

Spectral lightness rainbow colormap

Spectral lightness rainbow Quick post to share my replica of Ethan Montag ‘s Spectral lightness colormap from this paper. My version has a linear Lightness profile (Figure 1) that increases monotonically […]

New rainbow colormap: sawthoot-shaped lightness profile

Why another rainbow In the comment section of my last post Steve Eddins from Mathworks reported that some Matlab users prefer Jet to Parula, the new default perceptual colormap in Matlab, because within certain ranges […]

Visualizing colormap artifacts

In Evaluate and compare colormaps, I have shown how to extract and display the lightness profile of a colormap using Python. I do this routinely with colormaps, but I realize […]

Moiré Patterns

Moiré pattern Some time ago I reblogged a post from El Ojo Inoportuno showing Moiré pattern, which resulted from taking a photo of a circular pattern of (beautiful) tiles. This phenomenon is caused […]

What your brain does with colours when you are not “looking” – part 2

In What your brain does with colours when you are not “looking”, part 1, I displayed some audio spectrogram data (courtesy of Giuliano Bernardi at the University of Leuven) using 5 different colormaps to render the amplitude […]

Geophysical tutorial – How to evaluate and compare colormaps in Python

These below are two copies of a seismic horizon from the open source Penobscot 3D seismic survey  coloured using two different colormaps (data from Hall, 2014). Do you think either of them is ‘better’?  […]

New Matlab isoluminant colormap for azimuth data

I recently added to my Matlab File Exchange function, Perceptually improved colormaps, a colormap for periodic data like azimuth or phase. I am going to briefly showcase it using data from my degree […]

Colormap compromise

At the end the series The rainbow is dead…long live the rainbow! I introduced CubicYF, a rainbow-like color palette with a slightly compressive, monotonic increasing lightness profile. The red color is missing from the palette because green […]

Parula: a new Matlab colormap

Steve Eddins of the Matwork just published a post announcing a new Matlab colormap to replace Jet. It is called Parula (more to come on his blog about this intriguing name). […]

What your brain does with colours when you are not “looking” – part 1

When I published the last post of my series The rainbow is dead…long live the rainbow! there was a great discussion in the comments section with Giuliano Bernardi, a Ph.D. student at the University of […]

Visualize Mt St Helen with Python and a custom color palette

Evan Bianco of Agile Geoscience wrote a wonderful post on how to use python to import, manipulate, and display digital elevation data for Mt St Helens before and after the infamous […]

Convert color palettes to python matplotlib colormaps

This is a quick post to show you how to import my perceptual color palettes – or any other color palette – into Python and convert them into Matplotlib colormaps. We […]

Some photos of Northern British Columbia wildlife and geology

Introduction Last week I went  on a helicopter ride with Gerry, my father in-law, to count of Kokanee Salmon in the  Camp Creek near Valemount, BC. We were invited by Curtis Culp of Dunster, BC, which is […]

Beautiful Geology from space

In my post Our Earth truly is art I talked about Earth as Art, NASA’s  e-book collection of wonderful satellite images of our planet, and posted my top 3 picks. In NASA’s Perpetual Ocean […]

Mo(r)iré

Originally posted on El Ojo Inoportuno:
Matteo:I love this photo (thanks to Carlos Mario del Rio for posting it)! There’s something about tiled floors (and tiles in general) that has always mesmerized me and this is a really […]

Android seismograph app evaluation

Introduction Over the last couple of years I have looked at a number of apps of all sorts. Some were seismometers. Out of those, two had the desired (to me) […]

NASA’s Perpetual Ocean animation

A couple of months ago AGU blogger Dan Satterfield posted a great article titled The Turbulence of Van Gogh and the Labrador Shelf Current. For getting maps and art together, I […]

NASA Worldview satellite image browser adopts MyCarta perceptual rainbow

I was thrilled this week to learn from Ryan Boller that his team at NASA’s ESDIS Project included MyCarta’s perceptual rainbow (the CubicYF) as one of the palettes for the Worldview satellite imagery browser. If you’d like […]

An introduction to color palettes for seismic amplitude – teaser

Introduction In a future posts I will take a look at some of the color palettes used for seismic amplitude display, and discuss ways we can design more perceptual and […]

Color palettes for seismic structure maps and attributes

I created three color palettes for structure maps (seismic horizons, elevation maps, etcetera) and seismic attributes. To read about the palettes please check these previous blog posts: The rainbow is dead…long […]

Perceptual rainbow palette – the goodies

Perceptual rainbow palette – Matlab function and ASCII files In my last post I introduced cubeYF, my custom-made perceptual lightness rainbow palette. As promised there, I am sharing the palette  with today’s post. […]

Perceptual rainbow palette – the method

With this post I would like to introduce my new, perceptually balanced rainbow color palette. I used the palette for the first time in How to assess a colourmap, an essay […]

Edge detection as image fidelity test

This post is a quick follow-up to Dithering, a very interesting post by Cris Luengo, developer of DIPimage, a free Matlab image analysis toolbox. Dithering is a graphic method that arranges black and […]

Our Earth truly is art

NASA has published a number of really good e-books on planetary science. Typically, each time I stumbled on one, I added a link on my Books page, but I could […]

Comparing color palettes

Introduction In my last post I introduced a CIE Lab linear L* rainbow palette from a paper by Kindlmann et al. [1]. I used this palette with a map of South America created with data from […]

The rainbow is dead…long live the rainbow! – Perceptual palettes, part 5 – CIE Lab linear L* rainbow

Some great examples After my previous post in this series there was a great discussion on perceptual color palettes with some members of the Worldwide Geophysicists group on LinkedIn. Ian MacLeod shared some really […]

Visualization tips for geoscientists: Matlab, part III

Introduction Last weekend I had a few hours to play with but needed a short break from writing about color palettes, so I decided to go back and finish up […]

The rainbow is dead…long live the rainbow! – The rainbow is dead…long live the rainbow! – Perceptual palettes, part 3

Inroduction Following the first post in this series, Steve commented: Matteo, so would I be correct in assuming that the false structures that we see in the rainbow palette are caused […]

The rainbow is dead…long live the rainbow! – series outline

The rainbow is dead…long live the rainbow! – Part 1 The rainbow is dead…long live the rainbow! – Part 2: a rainbow puzzle The rainbow is dead…long live the rainbow! – Part […]

The rainbow is dead…long live the rainbow! – The rainbow is dead…long live the rainbow! – Perceptual palettes, part 2: a rainbow puzzle

ROYGBIV or YOGRVIB? If you are interested in the topic of color palettes for scientific data, and the rainbow in particular, I would say you ought to read this 2007 […]

The rainbow is dead…long live the rainbow! – Perceptual palettes, part 1

Introduction This is the first  post in a series on the rainbow and similar color palettes. My goal is to demonstrate it is not a good idea to use these […]

A good divergent color palette for Matlab

INTRODUCTION Before starting my series on perceptual color palettes I thought it was worth mentioning an excellent function I found some time ago on the Matlab File Exchange. The function is […]

A rainbow for everyone

Traffic lights for everyone Stephen Westland of Colour chat recently posted about a clever new LED traffic light developed in Japan. Here’s my tweet with the link to Westland’s original blog […]