We'll need maps when we go to Mars, too. At least, that's the thinking behind British mapping organisation Ordnance Survey's new map of the Martian landscape, which presents an otherworldly location in a format earthly ramblers will find familiar.
"There's certainly no reason why you couldn't imagine a future where someone might actually use a map on Mars in the same way that they would use a map on Earth," said cartographic designer Chris Wesson, who made the map of a patch of Martian topography 3672 by 2721 km across, to a scale of 1:4 million.
Wesson started designing the map after he was approached by planetary scientist Peter Grindrod from Birkbeck, University of London, who asked if he could help turn Mars data—most of which is open sourced from NASA—into something that resembles an OS map more than a scientific diagram.
"The initial objective was to take what was essentially the basis of a map for an area of Mars, and see if we could make it have more of the look and feel of an Ordnance survey map," explained Wesson.
The hardest part, Wesson said, was getting his head around the different landscape.
He wanted to keep things simple; the majority of his map is based on elevation data and place names, much like a regular map of Earth. "So actually in principle the process was pretty much the same as we would do for an OS map anyway, but obviously it looks a lot different in terms of the nature of the landscape," Wesson said.
In the future, he imagines that other people could add different overlays, for example, to show landing sites or traverse routes. Ordnance Survey is currently running a competition with the Times to come up with a symbol to represent a Mars landing site (one point of interest that isn't usually found on OS maps).
The hardest part, Wesson said, was getting his head around the different landscape. Unlike the Earth, where countries are coloured by mountains and valleys, it was a challenge to show the expanse of flatness on Mars, and to pick out both huge craters and also, for example, rocky areas that had little elevation difference.
"Things like being able to come up with a sensible contour interval and move the contours so they look nice and to make them more legible—that was something that was quite hard to achieve," he said.
The map is published on Flickr with a paper version envisaged. It may be a while before human tourists need a Martian navigational guide, but it comes in good time for robotic missions such as the European Space Agency's ExoMars, which Grindrod is involved with, which will be launching in 2018.
"There's a rather rude term, if I may use it, for map enthusiasts: 'bobble hats,'" said Wesson. "I'm not sure what the Martian equivalent to that would be."