One of my favorite features in Google Maps is the terrain layer, which provides a shaded relief (aka hillshade) view of the topography derived from a digital elevation model. Google has done a nice job generating a visually pleasing terrain layer, and we use it for all of our Google Maps-based interfaces in OpenTopography. Google appears to use a range of digital elevation model data sources to derive the terrain layer. Throughout the US, it appears that the terrain layer comes from either 10 or 30 m (1/3 arc-second & 1 arc-second respectively) DEMs from the USGS National Elevation Dataset (NED). Globally the terrain data appear to be derived from either Shuttle Radar Topography Mission (SRTM) data or something like the NOAA Global Land One-km Base Elevation Project (GLOBE) dataset. Recently however, I've begun to notice higher resolution data in the Google Maps terrain layer. These higher-resolution data are localized, and are patched into the terrain layer among the standard 10 and 30 m derived images, but they are impressive when you find them. Based on the location of these patches of high-resolution terrain, and their appearance, it is pretty easy to deduce that Google is now incorporating bare earth LiDAR digital elevation models into the Google Maps terrain layer.
Thus far, I've noticed high-resolution data in downtown Portland, OR, the greater Los Angeles area, and Mount Saint Helens in Washington. There may be other examples of LiDAR-derived terrain in Google Maps since I haven't searched very hard. If you are aware of other areas leave a comment.
Below are a few sites in Google Maps where you can clearly see the high-resolution data.
Downtown Portland, OR. Data are sourced from the Oregon LiDAR Consortium managed by the Oregon Department of Geology and Mineral Industries (DOGAMI). Note obvious building foundations, hillslope modifications, etc.:
Edge of LiDAR near Washington Park in Portland - bare earth LiDAR on the east side, 10 m (?) data on the west:
LiDAR bare earth data near Beverly Hills, CA. I'm not sure of the origin of these data - does anyone know if the original LiDAR point cloud and DEM data are publicly available?:
Obvious seam between LiDAR grids and lower resolution terrain data north of Yorba Linda, CA:
Finally, the very impressive Mount Saint Helens data. Presumably these are the data collected by NASA in partnership with USGS in 2003-2004 during a period of significant volcanic activity:
It is really nice to see these high-resolution terrain datasets making it into such a common and easily accessible platform like Google Maps. OpenTopography provides network-linked KMZ files to deliver LiDAR derived imagery data to Google Earth so that they are available to non-expert users, and direct incorporation of these data into the Google Maps terrain layer takes the accessibility of these data one step further. As the number of public domain LiDAR data collections increases, I'd expect that we'll see more examples of LiDAR appearing in maps and online visualizations accessible to the general public.
An interesting, and logical follow on question to LiDAR in Google Maps, is when will Google will tackle the integration of high-resolution terrain data into the topographic mesh in Google Earth? For the Earth science community, 1 meter terrain data in Google earth would be revolutionary.