I am having trouble converting latitude and longitude. Both are in
double precision in the table.
So, I am doing this
UPDATE my_table
SET geom = ST_PointFromText('POINT(' || longitude ||' '|| latitude
||')', 4326)
But, when I do this
SELECT ST_PointFromText(geom ) FROM my_table
I am getting an error
ERROR: parse error - invalid geometry
HINT: "0101000020E6100000D" <-- parse error at position 19 within
geometry
CONTEXT: SQL function "st_pointfromtext" statement 1
thanks
On Apr 26, 9:57 am, Jani Tiainen <rede...@gmail.com> wrote:
> 25.4.2012 19:17, vishy kirjoitti:
>
> > Hi,
>
> > I need to do spatial queries like find places within 5 miles of a
> > location given in latitude and longitude. So, I am thinking of
> > exploring PostGIS and GeoDjango. I have installed both. Now, I already
> > have a database which has a table for places with latitude and
> > longitude. Can I enable this db to use postgis and add column to this
> > table? Or, do I have to create a separate spatial db, create a table
> > with a column of geometry type and import data into that table (from
> > places table).? If I can use the existing database, how do I enable it
> > to use PostGIS?
>
> It depends on your environment but basic workflow is same is in *nix
> instructions. And it's not even hard. :
>
> createdb yourdatabase
> createlang plpgsql yourdatabase
> psql -d yourdatabase -f postgis.sql
> psql -d yourdatabase -f postgis_comments.sql
> psql -d yourdatabase -f spatial_ref_sys.sql
>
> Of course in your case you can skip creation of database. Just create
> language and install postgis stuff.
>
> After that you need to make sure that your database user has access to
> geometry_columns and spatial_ref_sys tables.
>
> Add new column (For PostGIS 1.5.x, newer postgis has simpler alternative
> syntax):
>
> SELECT AddGeometryColumn('my_table', 'my_geom', 4326, 'POINT', 2)
>
> And after that just update new geometry column:
> update my_table set my_geom = GeomFromText('POINT(' + x + ' ' + y +')',
> 4326)
>
> And don't forget to commit. If you have lot's of geometries (1M+) you
> probably want to drop out spatial index and recreate it afterwards.
> Otherwise building index takes just long time.
>
> --
> Jani Tiainen
>
> - Well planned is half done and a half done has been sufficient before...
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