Glyph (a stupid name, but it does start with g), graphs the dependencies between Go packages.
The program has no options, and presents a web interface on port 8080 on all interfaces. The various visalisations are registred as top level handlers. Here are some examples
http://localhost:8080/tree/io http://localhost:8080/radial/math/rand http://localhost:8080/forcegraph/fmt http://localhost:8080/chord/cmd/go
Glyph works sort of like godoc.