Monday, February 18, 2019

Earth's Light Mountains

Last year Jacob Wasilkowski released an interactive map which visualized Nasa’s nighttime lights data as as elevation data. In other words the Earth at Night map shows light pollution around the world in 3D as mountains of light.

NASA's so called Black Marble map is made by combining the best cloud-free satellite images of every land mass area of the Earth. The result is a map which shows the distribution of artificial lights around the world. Jacob has used NASA's data on light pollution to create an interactive map of the world which shows the brightest areas as high peaks and the darkest regions as valleys and plains.

Jacob has now released a 'how to' guide explaining how he created the map. Obviously converting NASA's light pollution map into a 3D elevation map includes a number of steps. One of these steps was to use chroma.js to convert every light pixel on the Black Marble map into a number range, which could then be used to visualize the luminosity values as elevation heights.

Using the metaphor of elevation is becoming a popular method of visualizing data on 3D maps. We've seen this most recently on the Pudding's Human Terrain interactive map. The Pudding's map shows population density across the globe using 3D population pyramids. The taller a pyramid block on the Pudding map then the higher the population.

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