This is the Salzburg Database of Geometric Inputs.
All geometric graphs on this page are in the public domain. Attribution to
this service is appreciated.
See the start page for more.
The Salzburg image on the front-page has been downloaded from Wikimedia
and resized using
convert -geometry '1123x1000'. The skeletal structure, that is embedded in the image, was constructed using surfer2.
It is a public domain image and was drawn in 1844 by Jakob Alt.