Problem solved! Many, many thanks!
In the end, I worked my way thought the entire database (good job I found the hitch before it grew too much) and changed all the individual ID's, as just changing the Preferences to IDs without the "-" didn't seem to effect the total change. On reflection, I have a feeling that if I had restarted Gramps  after changing the Preferences, then it  might have changed the individual entries after all. However, it's done now, and the Relationship graphs are working perfectly.

Incidentally, my original reason for including the "-" was to avoid confusing the" I" with the figure "1".

My only remaining cause of bafflement is what changed between the early reports I did which were OK and my recent ones which produced the duff graphs. I thought I had included the "-" in the ID's from the very start of using Gramps. But perhaps old age has made me forgetful!

Anyway, I'm content to leave that particular puzzle, and simply glad to get this very fine programme back on track.

Thanks again - it's reinforced my conviction that the Open Source community is unbeatable for giving support to users.

Brian B

Alex Roitman wrote:

On Sat, Jan 29, 2005 at 12:26:27PM +0000, Brian Blandford wrote:
I'm sorry for the confusion: I suspect the first email went to the wrong
list ( instead of I also suspect that my attachments
made it too large for inclusion - I received a reply saying it was
awaiting the moderator's decision as it exceeded the 40KB limit)

I figured this much later that day -- they had a problem with mailing
lists on so that there were few hour delays and duplicated
mailings, so it was a mess so start with :-)

To simplify things: I am getting print-outs from the Graphviz
Relationship graphs that make no sense to me: they show arrows emanating
from a single box to a column of names from my database, with, in the
case of an "Entire database" graph, the rest of the names from the
database extending above it. Formerly the printouts were correct, but I
haven't generated them for some time, and I have upgraded Gramps a
couple of times since then.

I attach a  .dot file as an example.

Now that I looked at your dot file, I see no problem with your database.
The reason that the dot screws up a perfectly valid structure turns out
to be simple. The IDs in your database are of the form "I-123", i.e.
they include dashes. The IDs are used in dot file to represent the node's
identity, and the dashes mean links between the nodes for dot (graphviz).
In short, the I-123 means the link from node I to node 123. So a single
node I was linked in the output to almost all of the others.

After I had replaced all I-123 with I123 and so forth, the resulting
graphs produced by dot turned out to be every bit as healthy as they
should :-)

As for the way to fix your situation: you may simply replace all the "I-"
with "I" in every dot file you generate. This is tiresome. Another way
would be to reorder gramps IDs i your database, which procedure should
use the prefix patterns defined in the preferences.

In the long term, we may be able to fix this by maybe quoting the node
names -- I haven't tried it yet, but I assume it should be possible.

In any case, there's nothing wrong with the relationship structure
in your database, so re-entering the data is definitely not necessary :-)

I'll let you know if we can work around the dashes for the next release.