[postgis-users] build a polygon from points

[nicklas.aven at jordogskog.no]

of course not as aline, but as apolygon/Nicklas 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 apolygon from pointTable

2009-06-23 nicklas.aven at jordogskog.no wrote:

>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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