[postgis-users] build a polygon from points

Caspa caspa.andre at gmail.com
Tue Jun 23 00:39:03 PDT 2009


yeah this could be the solution...unfortunately I have postgis version 1.3.5
and i doesn't have this feature yet..(I'm on debian system and don't want to
build from source)


>SELECT ST_MakePoly(ST_>LineFromMultiPoint(ST_collect(coord1, coord2,
coord3, coord4, coord5, coord1 ))) from table

this doesn't work, but I'm trying to use LineFromMultiPoint in other
ways...maybe it works...

THANKS

SELECT ST_MakePoly(ST_LineFromMultiPoint(ST_collect(coord1, coord2, coord3,
coord4, coord5, coord1 ))) from table


2009/6/23 <nicklas.aven at jordogskog.no>

>  About st_makeline an array is needed like this example:
> select st_makepolygon(ST_MakeLine(array[st_point(3, 2),st_point(2,
> 2),st_point(3, 3),st_point(2, 5),st_point(5, 5),st_point(3, 2)]));
>
> greetings
> Nicklas
>
>
> 2009-06-23 Caspa wrote:
>
> Hi, thanks for that,
> >those are colunm in the table :
> >
> >       coord1  |     coord2    |  coord3       |  coord4      |  pol
> > ----------------------------------------------------+--------------------
> >  geom_data | geom_data | geom_data | geom_data |  I WANT THIS
> >
> >I tried with this but didnt work;
> >
> >SELECT ST_MakePoly(ST_MakeLine(coord1, coord2, coord3, coord4, coord5,
> coord1 ) from table
> >
> >the problem is that I can't make i line from more than two points ( i'm
> using postgis v 1.3.5 and geometry *ST_MakeLine*(geometry[] point_array);
> doesn't work)
> > I'm trying to figure out how to use
> >
> >geometry *ST_MakeLine*(geometry set pointfield);
> >
> >but how do I build a geometry set pointfield???
> >sorry...really beginner!!
> >
> >
> >
> >
> >
> >
> >>
> 2009/6/22 Paragon Corporation <lr at pcorp.us>
> >Andrea,
> > Are those individual records or columns in the table?
> >
> > Take a look at ST_MakeLine, ST_MakePolygon, ST_BuildArea
> >
> >postgis.refractions.net/documentation/manual-svn/ST_MakeLine.html
> >
> >postgis.refractions.net/documentation/manual-svn/ST_BuildArea.html
> >
> >postgis.refractions.net/documentation/manual-svn/ST_MakePolygon.html
> >
> >
> > You build a line from points with ST_MakeLine and then do a ST_BuildArea
> or
> > ST_MakePolygon depending on your desired effect.
> >
> > Leo
> >>
> >
> >
> >
> >
> > -----Original Message-----
> > From: postgis-users-bounces at postgis.refractions.net
> > [mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of
> Caspa
> > Sent: Monday, June 22, 2009 10:15 AM
> > To: postgis-users at postgis.refractions.net
> > Subject: [postgis-users] build a polygon from points
> >
> > Hi everybody,
> > I'm new to postgis...
> > how can i build a polygon starting from points and not from x,y coord?
> >
> > i have a table built like this:
> >
> > point1 | point2 | point3 | point4 | polygon
> >
> > guess i have to use MakeLine and MakePolygon but i can't fugure out
> why...
> > thanks in advance
> >
> > Andrea
> >
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> >
>
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