For years now Google Earth has had a “display 3D buildings” option: turn this on, and the terrain becomes dotted with building models that have been deliberately created for the program. Given how many buildings actually exist in the world, it’s not possible for artists to model every single one of them, so the content was generally restricted to major urban structures - skyscrapers, shopping malls, Eiffel Tower, that sort of thing.
Lately Google Earth is displaying 3D content of a decidedly different style and extent. In many areas, individual trees are being rendered in 3D, as well as single-family homes. The shapes are somewhat “organic” and irregular, as if they are being generated from noisy (but actual) measurements instead of having been constructed by a designer using solid-model software.
So what’s going on? How is GE modeling individual trees and houses over large areas? Where is the data coming from?
Although prior to that, the 3D buildings were mostly generated by individual users, and there were definitely some areas that were pretty comprehensively populated by someone with entirely too much time on their hands.
My subdivision has had this feature for a few months now. We have lots of mature trees so the trees pretty much overwhelm the houses, especially the ranch style ones.
The 3D data comes from aerial photographs. Software compares photographs of the same location taken from different angles and extracts the 3D information automatically.
Apple, for example, acquired the image processing software for the 3D views in iOS Maps from a company called C3 Technologies in 2011. There’s a couple of explanatory videos in this article.
That’s my point though: the features no longer appear to be manually rendered on a 3-D cartesian grid. The objects being rendered now include trees and individual houses, and all appear to be automatically generated based on real-world measurements.
They’re generated from LIDAR, which is very detailed imaging of the surface of the earth done by shining multiple laser beams from aircraft. I believe Google and Nokia are also doing some LIDAR from their “street view” vehicles as well, making it possible to model the underside of tree canopies and eaves on houses.
Where do you see these auto-3Ded areas in Google Earth? (lat long coords?) I don’t doubt you, I just didn’t realize Google was doing that alongside Apple and Nokia.
If Google is using the same technology from C3/SAAB, it’s not LIDAR but aerial photos like hammos1 said. I don’t think aerial LIDAR usually has that kind of resolution, enough to pinpoint specific trees on a road, the angle of building steeples, etc., does it?
Sure. Just one example here (PDF), but there’s lots of this kind of work going on. Having an inventory of every single tree in a forest would be very valuable for forestry planners.