The Elevation Multiple Locations .NET Sample Code demonstrates how to get elevations for all DEM intersections. It can be generalized and return only points where elevation change is relevant, keeping the local maxima.
Gowalla, Foursquare, Yelp, Facebook Places, the list goes on. There's certainly no shortage of methods to tell people where you are and what you're doing while you're there. Startup Whatser, built on the SoGeo API for location-based apps, has jumped into the ring with a different approach to check-in services: to be useful.
There is a restaurant near my house that I go to often, it’s hard to find and I have trouble explaining to my friends how to get there. I can’t help but wonder how much business this restaurant is losing because of its poor location. Indoor mapping company EveryScape might have the solution. It's like Google Maps street view that doesn’t stop at the front door, it goes right inside. The Everyscape API can seamlessly be integrated into a website, allowing a developer to place the company’s immersive viewer in a relevant section of their site.