Postgres Pro
Downloads
Home   >   mailing lists

Thread: beginner postgis question lat/lon

beginner postgis question lat/lon

From
shadrack
Date:
Hi,
This may seem like a very simple question...it is...but I can't find
documentation on it to help. I've seen some posts about lat/long but
none that give simple solutions on how to insert lat/long in tables.
I'm a new user to postgis...I've been using mysql for a while but
needed the spatial functions so just recently downloaded postgresql/
postgis.
How do I create a simple table with several linestrings that have
coordinates in latitude/longitude?
Eventually, I'd like to create polygons with coordinates in lat/long
and see if they intersect various linestrings, but I'm trying to start
out simple.
Here's what I've done so far...

postgis=# \d routes_geom;
         Table "public.routes_geom"
 Column |         Type          | Modifiers
--------+-----------------------+-----------
 id     | integer               |
 name   | character varying(25) |
 geom   | geometry              |
Check constraints:
    "enforce_dims_geom" CHECK (ndims(geom) = 2)
    "enforce_geotype_geom" CHECK (geometrytype(geom) =
'LINESTRING'::text OR geom IS NULL)
    "enforce_srid_geom" CHECK (srid(geom) = 4326)
postgis=# insert into routes_geom values(1, 'J084',
GeomFromText('LINESTRING(38.20 -121.00, 38.20, -118.00)', 4326));

I receive this error:
ERROR:  parse error - invalid geometry
CONTEXT:  SQL function "geomfromtext" statement 1

Do you have a good way to input lat/lon and do spatial relationships
using lat/long coords?
Thanks for any help,
Shad

Re: beginner postgis question lat/lon

From
Martijn van Oosterhout
Date:
On Wed, Feb 27, 2008 at 04:59:07PM -0800, shadrack wrote:
> postgis=# insert into routes_geom values(1, 'J084',
> GeomFromText('LINESTRING(38.20 -121.00, 38.20, -118.00)', 4326));
>
> I receive this error:
> ERROR:  parse error - invalid geometry
> CONTEXT:  SQL function "geomfromtext" statement 1

You have an extraneous comma after the 38.20.

Have a nice day,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> Those who make peaceful revolution impossible will make violent revolution inevitable.
>  -- John F Kennedy
Attachment

Re: beginner postgis question lat/lon

From
Michael Fuhr
Date:
On Wed, Feb 27, 2008 at 04:59:07PM -0800, shadrack wrote:
> This may seem like a very simple question...it is...but I can't find
> documentation on it to help. I've seen some posts about lat/long but
> none that give simple solutions on how to insert lat/long in tables.

See the PostGIS documentation, in particular Chapter 4 "Using PostGIS":

http://postgis.refractions.net/docs/ch04.html

(The site isn't responding right now; hopefully it'll be available
soon.)

> postgis=# insert into routes_geom values(1, 'J084',
> GeomFromText('LINESTRING(38.20 -121.00, 38.20, -118.00)', 4326));
>
> I receive this error:
> ERROR:  parse error - invalid geometry
> CONTEXT:  SQL function "geomfromtext" statement 1

There are two problems with the geometry string: the syntax error is
due an extra comma in the second pair of coordinates, and coordinates
should be (X Y) therefore (lon lat) instead of (lat lon).  Try this:

insert into routes_geom values(1, 'J084', GeomFromText('LINESTRING(-121.00 38.20, -118.00 38.20)', 4326));

You might wish to subscribe to the postgis-users mailing list if you
have additional questions.

--
Michael Fuhr

Re: beginner postgis question lat/lon

From
shadrack
Date:
Thanks for the help!  Stupid error,
Shad

On Feb 28, 7:04 am, m...@fuhr.org (Michael Fuhr) wrote:
> On Wed, Feb 27, 2008 at 04:59:07PM -0800, shadrack wrote:
> > This may seem like a very simple question...it is...but I can't find
> > documentation on it to help. I've seen some posts about lat/long but
> > none that give simple solutions on how to insert lat/long in tables.
>
> See the PostGIS documentation, in particular Chapter 4 "Using PostGIS":
>
> http://postgis.refractions.net/docs/ch04.html
>
> (The site isn't responding right now; hopefully it'll be available
> soon.)
>
> > postgis=# insert into routes_geom values(1, 'J084',
> > GeomFromText('LINESTRING(38.20 -121.00, 38.20, -118.00)', 4326));
>
> > I receive this error:
> > ERROR:  parse error - invalid geometry
> > CONTEXT:  SQL function "geomfromtext" statement 1
>
> There are two problems with the geometry string: the syntax error is
> due an extra comma in the second pair of coordinates, and coordinates
> should be (X Y) therefore (lon lat) instead of (lat lon).  Try this:
>
> insert into routes_geom values(1, 'J084', GeomFromText('LINESTRING(-121.00 38.20, -118.00 38.20)', 4326));
>
> You might wish to subscribe to the postgis-users mailing list if you
> have additional questions.
>
> --
> Michael Fuhr
>
> ---------------------------(end of broadcast)---------------------------
> TIP 3: Have you checked our extensive FAQ?
>
>                http://www.postgresql.org/docs/faq