I am working on an application that requires the elevation at a given lat/long coordinate for lots of closely spaced coordinates along any given irregular path. (The path is a trace of a glider/hang-glider flight.)
I could use SRTM/GTOPO30/GLOBE data but I only need small (but arbitrary) sections of the world at any one time so I'd like to avoid storing a DEM database locally.
There is also Google's elevation API (for use with their maps) but it has a usage limit of 2500 requests a day whereas my data can be tens of thousands of points. Plus querying a server so many times for closely spaced locations seems like a waste a bandwidth.
So, ideally, I'd like a tile server for small DEM tiles. I found this http://www.arcgis.com/home/item.html?id=1b48cd3b6276416784fe90a68c580a89 but the ArcGIS API guide doesn't contain any useful info about it. Has anyone actually used it? Are there any other similar services?