Re: [Gramps-users] Descendant Graph Query

[Alex R. <sh...@gr...>]

Tony,

On Mon, 2006-02-06 at 17:15 +1300, Tony G wrote:
> I have Graphviz installed. I have looked at the Relationship Graph under
> Graphical Reports and also under Code Generators. In the latter case I
> have looked at the dot file produced. I have been to the Graphviz web
> site and looked at the man page for dot. All a bit daunting really!
>=20
> I am not sure how to get the information I want into the dot file (e.g.
> the information I mentioned above) - there are not many additional
> options available in Gramps. Are you suggesting that I manually make up
> a dot file with the information that I want?

In theory you could do that. The dot file simply describes the
graph in the text form: nodes and edges (i.e. lines connecting
the nodes). Then the dot program would lay out the graph based
on that description. Depending on the size of your report
editing dot file manually could be easy or hard.

> Where can I go for some more information on setting up a dot file to
> produce the output that I want. As it is a descendant graph that in this
> case I am after, are there examples where this has been done through
> Graphviz producing something similar to the Gramps Descendant Graph that
> I could copy?

I was thinking that maybe you can start with the dot file produced
by gramps, and then tweak it to your liking. I am fairly clueless
about the magic of graphviz or what it takes to get a certain graph,
sorry :-(  Maybe Julio or Eero can offer some pointers?

> Incidentally, I noted that the children in a Relationship Graph are
> plotted in a random order, maybe to fit them in?

I am not sure. I remember Julio saying that the layout of the graph
does depend on the order in which the nodes are listed in the dot
file, so simply swapping nodes in the dot file may alter the layout.
However, I suspect this dependence is not straightforward and also
heavily depends on the rest of the graph. Sorry, I'm afraid I cannot
be of much more help here. If you want to find this out, maybe a
good idea would be to ask graphviz people?

We're simply dumping the nodes and the edges into dot file and then
leave things to graphviz. Laying out complex graphs is a science on
its own, we're not messing up with it :-)

Alex

--=20
Alexander Roitman   http://www.gramps-project.org