Ordnance Survey

When you think Mars, you probably think dusty, mysterious terrain. You probably don't think, let me just pull up this map of Mars to see the best way to get from this crater to that one. But British mapping agency Ordnance Survey (OS) has drawn out a map of the red planet that you could one day plug into your Mars rover's GPS, and it is pretty great.

The map is far from comprehensive—it only shows about 3.8 million square miles, or 7% of Mars' surface. Cartographers drew on data from NASA to put the map together, a process which took months. The resulting product is an accurate (if absurdly scaled at a ratio of 1:4,000,000) portrayal of a small portion of the Martian terrain.

In a blog post published on the OS website on Monday, Cartographic Designer Chris Wesson explained the differences between mapping Mars and mapping the Earth. "At first it took a while to get my head around the height information," he said, pointing out that it's hard to get a sense of elevation without sea level. "A lot of the area of the map is at a minus elevation. My over-simplistic understanding is that this is because the zero level is what would hypothetically be mean sea level if there was enough water on Mars to equate to Earth." Wesson added that compared to our own planet, "the surface is very bumpy but at such a large scale I had vast expanses of land that appeared flat relative to the craters each of several thousands of meters depth, hence the need for different lighting and surface exaggerations."

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Wesson said that the map isn't red because "using shades of just one color makes it harder to see and picture the landscape and all the features within it from a map. Red is also a very dominant colour that is not very supporting of thematic overlays such as landing sites or place names." Plus, he said, it's not like maps of Earth are strictly green and blue.

The map was commissioned by British scientist Peter Grindrod, who is working on the European Space Agency's ExoMars mission, set to send a rover to Mars in 2019.

In a statement, OS Director of Products David Henderson said, "the private sector and space agencies are currently in competition to land the first person on Mars. Becoming more familiar with space is something that interests us all and the opportunity to apply our innovative cartography and mapping tradecraft to a different planet was something we couldn’t resist."

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Let the space map race begin.

Danielle Wiener-Bronner is a news reporter.