Apologies for the cut-down site. It is a placeholder until I have time to properly replace the Drupal site that was here.
Weathermap is an open source network visualisation tool, to take data you already have and show you an overview of your network in map form.
Data is collected via plugins. Plugins are supplied for RRDtool, MRTG (RRD and old log-format), tab-delimited text files, SNMP, fping, external scripts, and Cacti-specific data. The RRDtool plugin means you have access to data from a large range of open source monitoring tools, including Cacti, Cricket, Zenoss, MRTG, Routers2, Munin, and many more. Other sources are supported via plugins or external scripts.
It also includes detailed documentation, and an interactive editor to make creating your own maps as painless as possible.
There is strong Cacti integration in particular, leveraging the Cacti plugin architecture to provide a management user interface, and access control for maps using Cacti's existing user database. Additional datasource plugins allow efficient access to data from Cacti's poller directly, and data from other Cacti plugins like THold and DSStats.
Weathermap is widely used by national and international ISPs, tier-1 carriers, internet exchanges, telcos, national academic networks, many Fortune 500 companies in finance, automotive, medical/pharma and other sectors, state and national government departments, schools and universities, and even a church.
The development version on github is currently halfway through a very significant refactoring/rewrite. I don't recommend it for production use!