This graph was generated using "JpGraph", an object oriented PHP based graphing library. The graph example comes from the article, "Picture it with JpGraph", by Michael Bordash, which appeared in the May, 2004 issue of Linux Magazine on page 50.
The home of JpGraph is an excellent source of information and the source for the most recent version of JpGraph. At the time of this writing, JpGraph requires PHP >= version 4.3.8. In addition, the PHP installatin must support the GD library which most modern PHP installations do.
The types of graphs that JpGraph support is very impressive. There is a test suite of examples available which include code snippets.
Today's date is Friday May 16, 08