Simple elevation profile service similar to google's elevation service [1]. Demo installation using freeDEM [2] data: http://karme.de/elevation-profile/demo?path=48.5,9|48.5,9.1&upsample=100&format=svg (additional) features: - open source - seamless stacking of multiple DEMs (it is really simple to add another DEM dataset if the format is supported by gdal [3]) - upsample polyline (keeping original input points and inserting equidistant additional points if needed) - wgs84 spheroid distance calculations git repository at: http://karme.de/git/elevation-profile If http overhead is a problem you might wish to use the elevation-profile tool providing a simple command line interface. You can use it either directly via pipes or in combination with good old (x)inetd [4,5] or socat [6]. For xinetd an example configuration is included and installed by default. The default configuration binds to 127.0.0.1 only. If you want to limit access to a specific user on localhost you can try using ident and hosts.allow/deny (unfortunately the lua socket library doesn't support unix domain sockets, otherwise I would change the default config to unix domain sockets). The lua client example in lua/ uses socat. Using apache2 I observed problems using mpm_event and I suggest to use mpm_prefork for now: a2dismod mpm_event ; a2enmod mpm_prefork [1] https://developers.google.com/maps/documentation/elevation/index https://developers.google.com/maps/documentation/javascript/elevation [2] http://karme.de/freedem [3] http://www.gdal.org/formats_list.html [4] http://en.wikipedia.org/wiki/Inetd [5] http://www.xinetd.org/ [6] http://www.dest-unreach.org/socat/socat-version2.html