Nagiosgraph is an open source tool to represent data collected by Nagios plugins as graphs; this is akin to what MRTG does. The tools makes use of RRD (cyclic) database to reduce load on the system. The tool works by intercepting so called performance data and creating graphs out of them. If the performance data are not available, the output should be parsed to create such data.
Nagiosgraph is aimed at visual representation, including built-in ability to zoom the graphs. Thus, it can create a graphical data monitoring representation, suitable for further use in reports and articles.