I am looking for a graphing tool which will allow me to visualise the flow of data from one node to another.
Certain node will point to other nodes. Some nodes may receive data from several nodes. The more that is received the larger the node should be.
I'm certain this kind of graph exists but I'm unsure of the name. Any help is appreciated.
The problem you are talking about the network flow, which is usually done on a weighted (possibly directed) graph.