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6 de Junio 2007

Google Earth More Realistic with Better Terrain

New high resolution terrain in Google Earth - Grand CanyonThere was a lot of news last week from Google. Much of the news had to do with Google Maps, APIs, KML search, and KML support on other platforms. However, this past weekend Google released an enormous amount of new imagery all over the world. But, even more significant in my opinion, was the release of new high resolution 3D terrain, or digital elevation model (DEM) data. The new data is 10-meter resolution. Google Earth's terrain data mostly comes from NASA's Shuttle Radar Topography Mission which is at best 30 meter and sometimes 90 meter in resolution. This means Google Earth's data for the western US and the Canaries is now three to nine times higher than before.

What does this mean? This means when you tilt your view in Google Earth while looking at the new data (using your middle mouse button, the slider in the top right, or your SpaceNavigator), you are seeing terrain features which more closely resemble reality. Also, since the terrain is more accurate, the satellite/aerial photos taken from above stretches over the terrain more accurately. This means the scenery looks much better. Those of you who are familiar with the western mountains should try it out. Two better-known examples: the Grand Canyon of Arizona and the Grand Tetons in Wyoming are good places to start.

Google had previously released high resolution terrain for the Swiss Alps (see a fly-through video). I'm expecting they will be adding more parts of the world with this 10 meter data as well. I've asked Google if they can share a map showing what regions the new data covers. Does anyone know where they are getting this data?

There are people interested in seeing higher resolution terrain for their countries in GE. See this execellent illustration of why high resolution terrain is important by Christian Sam who posted it at GEC. It uses a time animation to "extrude" high resolution terrain in a small area of Austria.

Enviado por FrankTaylor at 6 de Junio 2007 a las 10:04 AM

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  • Comentarios

    It's great to get higher resolution terrain. But, that just makes the mis-alignment with the imagery more apparent. Look at Half Dome in Yosemite to see how sad that magnificent rock looks when you tilt the view.

    I just love these improvements in both imagery and terrain. Now I'd like to see some method for matching the two so that a river, for example, is at the bottom of a canyon instead of on the side wall. I'd like to see some way that the user community could get involved in this effort.

    Enviado por: Ernie at 6 de Junio 2007 a las 11:05 AM

    The 10m elevation should be the USGS 10-m Digital Elevation Model data that covers much of the United States. I was involved with paying for the development of a small part of it for California, and it was vast improvement over the 30-m data that had previously been available. For GIS types, the data are available at http://seamless.usgs.gov/ for download & processing.

    Enviado por: MIGIS at 6 de Junio 2007 a las 11:26 AM

    This really was a significant upgrade for elevation. I admit I've wondered for a while how long it'll be to pull the NED data in - since it's been there for a while at USGS.

    I guess what I'm keeping an eye on now, is Intermap's European coverage at sub-meter, and what occurs after June 15th, when TerraSAR-X launches. It'll be a little while before collections are tested and the data will be available - but we're getting close to several launch dates that'll inject a little something into the industry again.

    In regards to re-registering the existing imagery, Ernie - I'm not sure it'd be a good idea to get everyone in the user-community involved with that process. The lower-resolution datasets are generally going to have some amount of offset tolerance, so it's expected with higher-res elevation. That's not to say that problematic areas or even regions of interest can't be rubber-sheeted or auto-ortho'd to the DEM. Just that I think they'd be better off focusing on high-resolution imagery to counter the offsets instead. (Just an opinion.)

    How do you eat an elephant? One bite at a time.

    Enviado por: Daniel at 7 de Junio 2007 a las 09:30 AM

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