[postgis-users] Removing tiny polygons

[Morten Sickel]

I never used it, but it should be along the lines discussed here:
http://gis.stackexchange.com/questions/49650/merge-polygons-in-postgis

if it is just a few, it should be doable to do manually - I don't know if
it is possible to do automatically in SQL

For each poly with area < some_limit{
   find largest neighboring poly
    // or smallest, or whatever were you are sure you'll get a
well-defined answer
   join the two polys
}

Morten


Astrid Bjørnerød skrev:
> Is there anyone you have written some sql-code for removing the small
> polygons onto one of the neighbor-polygons ?
> Any stabil functions for this task?
>
> Astrid
>
> -----Opprinnelig melding-----
> Fra: postgis-users-bounces at lists.osgeo.org
> [mailto:postgis-users-bounces at lists.osgeo.org] På vegne av Tom McCallum
> Sendt: 27. januar 2014 20:48
> Til: morten at sickel.net; PostGIS Users Discussion
> Emne: Re: [postgis-users] Removing tiny polygons
>
> Thanks Morten.  I wanted the first case, so that helps.
>
> On Mon, 27 Jan 2014 19:15:18 -0000, Morten Sickel <morten at sickel.net>
> wrote:
>
>> It depends on what you mean with "remove" - do you want to just have
>> the large polygons without the area that is covered by the small ones
>> or do you want to add the area of the small polygons onto one or more
>> of the larges? (e.g. how one typically wants to handle shiver
>> polygons)
>>
>> In the first case it is as easy as a query like
>>
>> select the_geom where ST_area(the_geom) > ...
>>
>> Morten
>>
>>
>> Tom McCallum skrev:
>>> Hi all,
>>>
>>> If I have a polygon geometry field which seems to be made up of a
>>> large number of tiny polygons and some larger ones, what is the best
>>> way to remove polygons below a certain size?  Would I need to
>>> preprocess this and save in a new table/record or can I dynamically
>>> do it?
>>>
>>> Thanks
>>>
>>> Tom
>>> _______________________________________________
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>>> postgis-users at lists.osgeo.org
>>> http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users
>>>
>>
>>
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