With version 78f8598852813e3cbcbf2892c6690a48951afc3d URLs in graph nodes seem to be broken. I'm not sure if this is a problem with GraphViz or with its usage of the ImageMap extension; probably the former, as the imagemap coordinates appear to be correct, but just have the wrong link applied.
With a graph defined like this:
<graphviz>
digraph example {
Mollusca [URL="[[w:Mollusca]]"];
Neomeniomorpha [URL="[[w:Neomeniomorpha]]"];
Mollusca->Neomeniomorpha
}
</graphviz>The following results:
Both of the links are to W:Mollusca. The tooltip above is shown where the cursor was above Neomeniomorpha.
The generated HTML is:
<map name="ImageMap_1_1084280109"> <area href="/wikimedia/mediawiki/index.php/W:Mollusca" shape="poly" coords="165,29,162,22,154,15,140,10,124,7,106,5,88,7,71,10,58,15,50,22,47,29,50,37,58,43,71,49,88,52,106,53,124,52,140,49,154,43,162,37" alt="W:Mollusca" title="W:Mollusca"/> <area href="/wikimedia/mediawiki/index.php/W:Mollusca" shape="poly" coords="206,125,201,118,187,111,165,106,137,103,106,101,75,103,47,106,25,111,10,118,5,125,10,133,25,139,47,145,75,148,106,149,137,148,165,145,187,139,201,133" alt="W:Mollusca" title="W:Mollusca"/> </map> <img alt="This is a graph with borders and nodes that may contain hyperlinks." src="/wikimedia/mediawiki/images/6/66/Main_Page_digraph_example_dot.png" width="212" height="155" usemap="#ImageMap_1_1084280109"/>