Running Route Planner
Picking a new running route of roughly the right length is more annoying than it should be. This pulls the walking network around a start point out of OpenStreetMap with OSMnx, builds a graph with NetworkX, and searches for loops close to a target distance.
Elevation comes from the Austrian 10 m digital terrain model, so a route can be scored on climb rather than just distance — a flat 10 k and a 10 k with 400 m of gain are not the same run.