It seems that GD::Graph::Map is inconsistent between graph types. In order to add links to data points for a line graph, you must pass the url list to the lhref option of the map object instead of the (documented) href option. For the pie chart, the href option is used. The linepoints graphs do not appear to work at all.

I'm still trying to track down the rollover problem. Suggestions are much appreciated.

Update:
This turns out not to work. lhrefs sets each href to the value of the first x-axis label. So there's a valid link, but it's essentially useless. Boo incomplete cpan modules that aren't documented as such.