##### THE FOLLOWING QUERY GIVES ME THIS ERROR :
# Warning: odbc_exec(): SQL error: [unixODBC][OpenLink][Virtuoso iODBC Driver][Virtuoso Server]SQ200: Stack Overflow in cost model, SQL state 37000 in SQLExecDirect in /var/www/html/ontowiki-scripts/model_the_source-virtuoso_to_webmap.php on line 20

##### BUT IT WORKS IF I COMMENT OUT (in the FILTER clause)
# AND
# bif:st_intersects ( ?geom, bif:st_geomfromtext("BOX(<?=$xmin?> <?=$ymin?>, <?=$xmax?> <?=$ymax?>)") )

##### AND IT ALSO WORKS IF I COMMENT OUT (in the FILTER clause)
# ?min_zoom <= "<?=$zoom?>"^^xsd:integer
# AND
# ?max_zoom >= "<?=$zoom?>"^^xsd:integer
# AND

##### SO IT'S ONLY WHEN I COMBINE BOTH THAT I GET THE ERROR ?!?!


PREFIX geo: <http://www.opengis.net/ont/geosparql#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX : <http://dhlabpc2.epfl.ch/OntoWiki/vtm/#>

SELECT *
FROM <http://dhlabpc2.epfl.ch/OntoWiki/vtm/>

WHERE{
    # select the entity
    ?entity a ?class .

    # whose class is a subclass of :class_entity
    ?class rdfs:subClassOf :class_entity .

    # get details for the subclass
    ?class rdfs:label ?subclass_label .
    ?class :zindex ?zindex .
    ?class :min_zoom ?min_zoom .
    ?class :max_zoom ?max_zoom .

    # that have a defined shape
    ?entity :shape_defined_by ?geometry_defining_entity .
    ?geometry_defining_entity geo:geometry ?geom .

    FILTER (
        ?min_zoom <= "<?=$zoom?>"^^xsd:integer
         AND
        ?max_zoom >= "<?=$zoom?>"^^xsd:integer
         AND
        bif:st_intersects ( ?geom, bif:st_geomfromtext("BOX(<?=$xmin?> <?=$ymin?>, <?=$xmax?> <?=$ymax?>)") )
    )

}
ORDER BY ?entity

LIMIT 500