Maps from another world

Friday, December 14, 2007 at 8:43:00 AM

Google Moon and Google Mars are great examples of what can be done with the Google Maps API. But in the rush to get both products out the door, we never quite got around to going the extra step and providing support in the Maps API itself for the tiles that Google Moon and Google Mars use. Until now, that is!

Fresh out of the oven, Maps API v2.95 includes explicit support for Moon and Mars map types. Want to plan your next moon landing, maintain a database of alien colonies, or just keep track of things you've lost on Mars? All these things and more are now just as easy to do as creating any other Maps mashup. The sky's the limit!

Speaking of the sky... while we were at it, we didn't stop at Moon and Mars tiles. We added support for Google Earth's sky imagery, too. That's right, you can now use the Maps API to create web-based versions of the cosmos, pulling from our huge tileset of merged telescope images. Note that we haven't yet perfected inter-galactic geocoding or driving directions, so you'll have to stick to Earth maps when you want to search for pizza joints and coffee shops. At least for now.

Michael Kosowsky of was kind enough to whip up some great example applications that make use of these new map types. You can use his Cosmic Visibility page to see and understand the phases of the Moon or Mars. You can even see where the planets are in the sky, and where the horizon is, custom-drawn for your specific time and location. We hope these are just the first of many science mashups created from this feature.

All of this is made possible by the following pre-defined GMapType constants, which were added in the v2.95 Maps API:

These work just like the familiar G_NORMAL_MAP and G_SATELLITE_MAP constants. See our examples for more info. As a teaser, here's a quick demo:

Be aware that the sky data is referenced to the celestial coordinate system, which takes some getting used to for us Earth-dwellers. The vertical axis is known as declination, and the horizontal axis is right ascension (which increases to the left, unlike longitude which increases to the right). A good search engine can be used to help you find more info on this coordinate system. We also have some documentation of our own on this topic, for those interested in overlaying KML on the sky in Google Earth. Note that KML isn't yet fully supported on sky maps, due to the coordinate system reversal.

Now go create some other-worldly maps!