[geos-devel] multipart polygon

[zhangjing]

hi,
=09thanks for ur replies,but from source code, i think all the topo=
 operations call   checkNotGeometryCollection first.  so how can=
 multipolygon supports topo operrations like union.

Geometry*
Geometry::Union(const Geometry *other) const
=09//throw(TopologyException *, IllegalArgumentException *)
{
=09checkNotGeometryCollection(this);
=09checkNotGeometryCollection(other);
}

void
Geometry::checkNotGeometryCollection(const Geometry *g)
=09//throw(IllegalArgumentException *)
{
=09if ((typeid(*g)=3D=3Dtypeid(GeometryCollection))) {
=09=09throw new IllegalArgumentException("This method does not=
 support GeometryCollection arguments\n");
=09}
}

class MultiPolygon: public GeometryCollection {
}
=09


>Multipolygons do support holes (they are simply collections of
>non-overlapping polygons), and they do support all geometry=
 operations.
>
>Martin Davis, Senior Technical Architect
>Vivid Solutions Inc.      www.vividsolutions.com
>Suite #1A-2328 Government Street Victoria, B.C. V8T 5G5
>Phone: (250) 385 6040 - Local 308 Fax: (250) 385 6046
>
>
>> -----Original Message-----
>> From: zhangjing [mailto:jingzhang at cbigroup.com] 
>> Sent: September 1, 2004 8:37 PM
>> To: geos-devel at geos.refractions.net
>> Subject: [geos-devel] multipart polygon
>> 
>> 
>> hi all,
>>    i wonder how can i use multipart polygon in geos, i think 
>> that polygon class only support single part polygon with 
>> holes , and multipolygon class does not support topological 
>> operations. and how can i support multipart polygon in my=
 program.
>> 
>> Best Regard.
>>    
>> 
>> 
>> 
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=3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D
=09=09=09

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=C0=F1=A3=A1
 
=09=09=09=09 
=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1zhangjing
=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1jingzhang at cbigroup.com
=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A12004-09-03