[postgis-users] return boundary

[Travis Kirstine]

I have a multipolygon that has consists mainland and island polygons.
I need to generate a single polygon / line that represent the boundary
of the multipolygon as a whole, something like a convex hull but
keeping the detail of the outer rings and joining the islands to the
mainland.  I have been try different combos of convex hull, buffer and
difference but can't get what I'm looking for.

Any thoughts would be greatly appreciated

Regards

-- 
Travis K.

Toronto, Canada
------------------------------------------------------------
"She knows there's no success like failure
And that failure's no success at all."
-Bob Dylan-
------------------------------------------------------------