Elevation: OpenTopoData / Mapzen — sources and licenses.
POST JSON to https://iotlab.omu.edu.tr/elevation/v1/elevation, with 1–100 locations.
{"locations":[{"latitude":41.3,"longitude":36.3}]}
Limited shared free API quota. Heights have source-dependent vertical references; they are not WGS84 ellipsoidal heights. No geoid conversion is performed.
Queried coordinates are sent to OpenTopoData and cached locally for up to 30 days.
Metadata and service limits