[postgis-users] how obtain the interior parcels

[Fred Lehodey]

Hi Salas,
not sure this is the better way, but.. ;-)
... (you need POLYGONs, use ST_Dump() if MULTIPOLYGONs)

you can try something like this:

SELECT ST_InteriorRingN((the_geom),s)
FROM your_parcels , generate_series(1,(SELECT
max(ST_NumInteriorRing(the_geom)) FROM your_parcels)) s
 WHERE ST_NumInteriorRing(the_geom) > 0
AND ST_InteriorRingN(the_geom,s) IS NOT NULL


Fred...



On Thu, Dec 10, 2009 at 8:13 PM, Fsalas <fsalas at geocuba.cu> wrote:

>  Thanks , Fred.
>
> Yes, I need the list of island polygons i use the ST_NumInteriorRings(),
> ... but only obtain the number , and i need obtain the list of feature
> island.
>
> How resolve this?
>
>  regards , salas
>
>
>
> -----Original Message-----
> From: Fred Lehodey <lehodey at gmail.com>
> To: PostGIS Users Discussion <postgis-users at postgis.refractions.net>
> Date: Thu, 10 Dec 2009 19:48:17 +0000
> Subject: Re: [postgis-users] how obtain the interior parcels
>
> Hi Salas,
> are "interior parcels" islands ?
>  ST_NumInteriorRings(geometry)
> Return the number of interior rings of the first polygon in the geometry.
> Return NULL if there is no polygon in the geometry.
> ST_NumInteriorRing(geometry)
> Synonym to NumInteriorRings(geometry). The OpenGIS specs are ambiguous
> about the exact function naming, so we provide both spellings.
>  ST_InteriorRingN(geometry,integer)
> Return the N'th interior ring of the polygon geometry. Return NULL if the
> geometry is not a polygon or the given N is out of range.
>
> Fred.
>
>
> On Thu, Dec 10, 2009 at 7:35 PM, Fsalas <fsalas at geocuba.cu> wrote:
>
>>  Hi,
>> I have a table parcels , and I need obtain the list of the only interior
>> parcels, the parcels is not overlap.
>> I test ST_Contains(), ST_Intersects() but the result is not correct.
>>
>> Salas.
>>
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>>
>>
>
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