[postgis-users] Merge function in PostGIS

[Paul Ramsey]

Or, possibly:

select buffer(the_geom,0.01) from tablename where geometrytype =  
'MULTIPOLYGON';


On 30-Oct-06, at 5:34 PM, Michael Fuhr wrote:

> On Mon, Oct 30, 2006 at 01:50:26PM -0700, Bruce Rindahl wrote:
>> I need a merge function in PostGIS.  What this means is if I have a
>> multipolygon and if any two parts share a common edge I need the  
>> union of
>> the two parts in one polygon.  For example if I have:
>> MULTIPOLYGON(((partA)),((partB)),((partC))) where partA and partC  
>> intersect
>> or share a common edge, the result will be:
>> MULTIPOLYGON(((Union of partA & partC)),((partB)))
>
> Something like this might work:
>
> SELECT GeomUnion(geom)
> FROM (SELECT (dump(the_geom)).geom
>       FROM tablename
>       WHERE ...) AS s;
>
> -- 
> Michael Fuhr
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