GvMap is an algorithm for visualizing graphs as maps. It is part of the Graphviz library, and was originally called the GMap Algorithm.
Information visualization can be invaluable in making sense out of large data sets. However, traditional graph visualization methods often fail to capture the underlying structural information, clustering, and neighborhoods.
VIMEO 121832862 Visualizing Graphs as Maps with Contiguous Regions
GvMap, provides a way to overcome some of the shortcomings with the help of the geographic map metaphor.
While graphs, charts, and tables often require considerable effort to comprehend, a map representation is more intuitive, as most people are very familiar with maps and even enjoy carefully examining maps.
Example
GvMap of co-authorship, where each node is an author and an edge exist between two authors if their name appears in a paper on one of the International Symposium on Graph Drawing 1994-2007 - graphviz.org 
This graph has authors as vertices and collaborations as edges. That is, there is an edge between two authors if they have collaborated on a paper.
This graph is cumulative, in the sense that two authors are connected with an edge if they have written at least one joint paper in the first ten years of the symposium.
The top 8 connected components are taken, and the graph is laidout using sfdp. A map showing the clustering relationship is generated using gvmap.
sfdp -Goverlap=prism -Gcharset=latin1 gd_1994_2007_8comp.gv | gvmap -e | neato -Ecolor="#55555522" -n2 -Tpng > gd_1994_2007_8comp.png
There is an entire site graphing computer science articles as maps, where you can create your own maps over at - arizona.edu
References and Links
GMap: Drawing Graphs as Maps (2009), Emden R. Gansner, Yifan Hu, and Stephen G. Kobourov - pdf
Putting Recommendations on the Map -- Visualizing Clusters and Relations (2009) - arxiv.org
Maps from "Putting Recommendations on the Map - research.att.com
Example maps over at arizona.edu
Professor Stephen G. Kobourov - arizona.edu
<H3>Man Page
gvmap is installed as part of the Graphviz package.
NAME gvmap - find clusters and create a geographical map highlighting clusters. SYNOPSIS gvmap [ options ] [ -o outfile ] [ files ] DESCRIPTION gvmap takes as input a graph in DOT format, finds node clusters and produces a rendering of the graph as a geographic-style map, with clusters highlighted as countries, in xdot format. In the input graph, each node must have position, width and height information (pos, width and height attributes, respectively) defined, and nodes must not overlap. By default, gvmap will generate the clusters from the data. If desired, the input graph can specify cluster information by giving every node a cluster attribute whose value is a small positive integer. (It is works best if cluster values are all integers in the interval [1,K] for some K. Nodes sharing the same cluster attribute value will be put into the same cluster. N.B. For the cluster attribute to be used, all nodes must have a valid value. If the -D flag is used, gvmap will use the top-level cluster subgraphs to determine the clustering. Any nodes not in such a cluster will be put into a sin- gle catch-all cluster. If the input specifies the desired clustering as described above, it can also specify a desired coloring by having some node in each cluster provide a clustercolor attribute. N.B. Unless one specifies -c0, only the clustercolor of the last node in a cluster has an effect. In addition, unless one uses -O, gvmap may permute the given colors.