NQuery or Query with overlapping planning regulations

[Carlo A. Bertelli (Charta s.r.l.)]

Hello,
we are working at the website of the will-be Urban Center for the
municipality of Genova, Italy.
By now we have a website with descriptions of public and private works
which is driven by interactive maps.
The prototype works fairly well, it is mainly cgi mapserver inside a
simple php custom made page and is supposed to become a cms driven
site that uses Kaistar (http://www.kaistar.org - a java based open
source cms).
I think the problem I'm going to explain could be easily solved in
php, but we are not going to use php as a long run solution.
The problem could be conceived as a conditional choice between query
and nquery and it's due to the specific nature of the geographic data.
We use maps to go from one page (about areas, or problems, or public
plans, or projects) to another.
If we have project data that describe new developments or complete
redevelopments, the problem does not arise. We will have projects
spread all around the town area that do not overlap, so when we click
on one area we can easily direct the user to a new page (a simple
template contains the reference to the relevant project).
All seems to work well.
But when we deal with planning regulationswe cannot always direct the
user to a single page. Sometimes regulations overlap. We should have
some logic (java based or, by now, php based) in between that:
* shows a page to let the user decide what page to go when multiples
pages (for multiple regulations) are possible;
* directly goes to the selected page when the query outputs only one page.
Do someone have a better representation of the problem or a clean
solution for this problem?
Just to understand what happens in the prototype, look at:
http://civis.comune.genova.it/uc5_web/
http://civis.comune.genova.it/uc5_web/interna.php?codp=RIGURB01_1
works well. This is the case of redevelopment;
http://civis.comune.genova.it/uc5_web/interna.php?codp=GEC_RECCS1
does not work as supposed. Multiple regulations overlap here.

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Carlo A. Bertelli
   Charta servizi e sistemi per il territorio e la storia ambientale srl
          Dipendenze del palazzo di Clemente Doria,
          vc. alla Chiesa della Maddalena 9/2 16124      Genova (Italy)
          tel. +39(0)10 2475439  fax +39(0)10 2475439  gsm:+39 333 2298345
   e-mail: bertelli at charta.acme.com      http://www.charta.acme.com
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