[postgis-users] visually linking the polygons of multipolygon layer

[pcreso at pcreso.com]

Looks simple enough, but you may need to find some way of ordering the centroids to have a sensible line progressing through the individual polygons.

I guess you could stick an order by X() or Y() of the centroid's coords so the lines always run EW or NS??


Cheers,

  Brent Wood


--- On Wed, 9/17/08, Obe, Regina <robe.dnd at cityofboston.gov> wrote:

> From: Obe, Regina <robe.dnd at cityofboston.gov>
> Subject: RE: [postgis-users] visually linking the polygons of multipolygon layer
> To: "PostGIS Users Discussion" <postgis-users at postgis.refractions.net>
> Date: Wednesday, September 17, 2008, 2:15 AM
> First thing that comes to mind to me is string the centroids
> together.
>  
> Something like
>  
> SELECT gid, ST_MakeLine(ST_Centroid(the_geom)) As arc
> FROM (SELECT gid, (ST_Dump(the_geom)).geom As the_geom
>                 FROM multipolytable
> ) As foo
> GROUP BY gid
>  
> Hope that helps,
> Regina
> 
> ________________________________
> 
> From: postgis-users-bounces at postgis.refractions.net
> [mailto:postgis-users-bounces at postgis.refractions.net] On
> Behalf Of erik
> Sent: Tuesday, September 16, 2008 9:06 AM
> To: PostGIS Users Discussion
> Subject: [postgis-users] visually linking the polygons of
> multipolygon
> layer
> 
> 
> Hi,
> 
> I'm not sure I know how to formulate this
> I have a set of Multipolygons. I'd like to link somehow
> the polygons of
> each multipolygon  with a "string", an arc, that
> expresses their
> belonging to the same polygon.
> 
> Is this possible, is there some predefined function that
> could
> accomplish this?
> 
> Many thanks,
> 
> Erik
> 
> 
> 
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