[postgis-users] build a polygon from points

[nicklas.aven at jordogskog.no]

ok, I missed to check aginst 1.3.x, sorry this I think is a workaroud:
select ST_PolygonFromText('POLYGON(('||st_x(p1)||' '||st_y(p1)||', '||st_x(p2)||' '||st_y(p2)||', '||st_x(p3)||' '||st_y(p3)||', '||st_x(p4)||' '||st_y(p4)||', '||st_x(p1)||' '||st_y(p1)||'))') AS aline from punkter; It's ugly  but it seems to work for me at 1.3.6 and should work on 1.3.5 as well /Nicklas

2009-06-23 Caspa wrote:

Yes, i saw it, but in postgis 1.3.5 geometry ST_MakeLine(geometry[] point_array);  is not implemented...
>
>gives error...
>
> here it is
>
>
>ERROR:  function makeline(geometry[]) does not exist
>LINE 1: SELECT MakeLine(ARRAY[MakePoint(1,2,3),MakePoint(3,4,5), Mak...
>
>you can check it here (just above example title)
>
>postgis.refractions.net/documentation/manual-svn/ST_MakeLine.html
>
>>
2009/6/23 <nicklas.aven at jordogskog.no>
> >
>ok> >you saw my second answer?>st_makeline should work if you just define an apoint array like>array[point1, point2,point2, point1]> >/Nicklas>
>
 >

>
> 2009-06-23 Caspa wrote:
>
> 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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