Here's the info about the tech from the blog: The data comes from http://www.OpenStreetMap.org http://www.OpenStreetMap.org. The software uses the Valhalla (h

Here's the info about the tech from the blog: The data comes from http://www.OpenStreetMap.org http://www.OpenStreetMap.org. The software uses the Valhalla (https://mapzen.com/projects/valhalla https://mapzen.com/projects/valhalla) routing engine to generate routes, and the Pelias geocoder (https://github.com/pelias https://github.com/pelias) to lookup names for points. Valhalla and Pelias were both developed by Mapzen (https://mapzen.com/ https://mapzen.com/), an open-source mapping lab dedicated to building open mapping tools that run on open data. All routes between 60°S and 60°N include elevation profiles that are generated from SRTM digital elevation models (http://www2.jpl.nasa.gov/srtm/ http://www2.jpl.nasa.gov/srtm/). The digital elevation models were obtained from the Open Terrain project (http://openterrain.tumblr.com/ http://openterrain.tumblr.com/), who provides easy access to terrain data that is freely available from US government sites, but hard to access.