problem: cannot easily render a map with pin on coordinates
This is now running at https://howlongistheline.org/maps
Simply request lattitude,longitude,API-key and it will return a map tile with a pin at the coordinates provided.
If you are going to be using this for something other than howlongistheline.org and expect a non-trivial number of requests you should request an API key. Otherwise use the public key: K3340
curl https://howlongistheline.org/maps/52.512411,13.381612,K3340 -o test.png
or simply open https://howlongistheline.org/maps/52.512411,13.381612,K3340 in your browser.