[postgis-users] build a polygon from points

[Caspa]

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
>
> http://postgis.refractions.net/documentation/manual-svn/ST_MakeLine.html
>
> http://postgis.refractions.net/documentation/manual-svn/ST_BuildArea.html
>
> http://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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