Lots of blogs (here and here) and news outlets have covered some of the great new Mars features in Google Earth. I will assume that you have read those blogs, watched various demonstration videos, or even watched some of the Guided Tours available in the Google Earth client itself. I will most certainly assume that you have at least taken a cursory spin around the Mars in Google Earth (we refer to it as Google Mars internally—at Ames and Google—but since that has meant the 2D Google Maps API Mars maps for so long, I don't want to confuse people).
For the discerning visitor I present a number of little perks that you might not notice. Mars in Google Earth is primarily targeted at a general public audience, but we've also slipped in some pretty cool extras (if I do say so myself) for scientists and advanced explorers alike.
- Load this image
- So if you have taken the 'Introduction to Mars' tour narrated by Ira Flatow, you have seen how some of the CTX footprints (orange polygon outlines) have a 'Load this image' link in their Info Balloons that when clicked actually load the CTX imagery as a KML Image Overlay, so that you can zoom in and around the full resolution of that CTX image. That's only a few, maybe someday we'll have more. However, there are two other places where there are some images with a 'Load this image' link, and those places are at the poles. As you may know, due to the single equatorial projection that Google Earth uses, imagery at the poles can look particularly bad. Even more so for those HiRISE images that are burned into the base layer up there. However, there is a little trick that you can use when building KML image overlays near the poles that mitigates the projection problems. We have done this with some of the polar HiRISE images, and so if you go to the poles and click on some HiRISE images, you'll see a 'Load this image' link that will bring in a better version of the HiRISE image to look at.
- MER Rover Waypoints
- You've certainly seen the traverse paths of the MER rovers in Gusev Crater and Meridiani Planum. For most people, just seeing where they have been is really pretty darn cool. We've put in a handful of the rover panoramas, but the rovers moved very slowly collecting data the whole way. Each place where the rovers stopped there is a ton of data. The MER Analyst's Notebook provides an excellent window onto the station-by-station data. Although off by default, you can turn on a Placemark for each waypoint which has its own Info balloon that links back to the Analyst's Notebook for that site. To turn on the waypoints, go to the U.S. flag icon at the beginning of either MER traverse. In the Info balloon for the flag placemark there is a 'Load rover waypoint data' link. Clicking on that loads up all the waypoints.
- Search box
- Don't underestimate the utility of the search box up there in the upper left. You can use it to find the locations of any formal Martian place names (Valles Marineris, Galle Crater, Cerberus Fossae, etc.), type in arbitrary longitude and latitude pairs, etc. However, you can also use it to find images. Google Earth knows the names of HiRISE, CTX, HRSC, CRISM, and MOC images (all the images it has in the 'Spacecraft Imagery' layer), so you can type in an image name, and Google Earth will take you to that location (although you'll need to turn on that imagery's 'Spacecraft imagery' layer to see the footprint and be able to bring up the Info balloon).
- HiRISE terrain
So Mars in Google Earth has topography. Globally, by default, we use MOLA gridded terrain. In many places where the HRSC imagery overlays the MDIM imagery in the basemap, there is also HRSC terrain—which is quite gorgeous when draped with HiRISE or CTX imagery. However, as of this writing there are four places where terrain models from HiRISE imagery have been incorporated, and we hope to bring in more as more HiRISE terrain models become available. So where are they? Well, two you've probably seen already. The whole area around the Spirit rover is a HiRISE terrain model, as is the area around Victoria Crater that the Opportunity rover visited. The other two areas are a little more obscure, and are just simply the result of good-looking terrain being available (for example, the terrain model around Phoenix was available, but not incorporated—because it was flat). The other two places are near Mawrth Valles (search for PSP_002074_2025) and part of a crater near the Hellas Montes (search for PSP_001714_1415).