[postgis-users] Questions about using SRID not -1

[ibrahim saricicek]

Hi,

Your table include objects, more than one projection.. So if there is any
object in different projection you can't set your table projection to
4326...

can you try this!!

Create a new geometry column "the_geom_4326"

then run this

UPDATE  table_name SET the_geom_4326=transform(the_geom,4326),

then use ST_SetSRID for the new column...

REgards,
ibo...


On Mon, Jan 18, 2010 at 7:23 PM, Oscar Zamudio <cmntlk at gmail.com> wrote:

> Hi everybody.
> I had no success with any of the recipes received here.
> Could it be that a table with data loaded without SRID explicit value has
> no chance of being updated later to the right one?
> Regards,
> Oscar
>
>
> On Sun, Jan 17, 2010 at 1:08 PM, Oscar Zamudio <cmntlk at gmail.com> wrote:
>
>> Ben,
>> I tried your intruction:
>>
>> UPDATE mypoints SET the_geom = ST_SetSRID(the_geom,4326);
>>
>> But I got:
>>
>> ERROR:  Operation on two GEOMETRIES with different SRIDs
>>
>> Regards,
>> Oscar
>>
>> On Sat, Jan 16, 2010 at 10:48 PM, Ben Madin <
>> lists at remoteinformation.com.au> wrote:
>>
>>> Oscar,
>>>
>>> you have a couple of options as I see it. In Postgres you could just
>>> update the geometries first.
>>>
>>> > UPDATE mytable SET the_geom = ST_SetSRID(the_geom,4326);
>>>
>>>
>>> And for next time, assuming your data originally had some sort of
>>> coordinate system (and it must have if it was spatial data), you can /
>>> should use the -s flag in shp2pgsql to provide 'SRID awareness'
>>>
>>> In your case, I would suggest -s 4326.
>>>
>>> ie (using -d to drop and replace existing table
>>>
>>> $ shp2pgsql -s 4326 -d myshapefile myoldtablename | psql mydatabase
>>>
>>>
>>> In geometry terms, I think it is unlikely that your data was stored
>>> (spatially) as sexagesimal degrees, although it may be displayed as such in
>>> your GIS.
>>>
>>> cheers
>>>
>>> Ben
>>>
>>>
>>>
>>>
>>>
>>> On 17/01/2010, at 2:54 , Oscar Zamudio wrote:
>>>
>>> > Hi,
>>> > I'm have problems to transform my spatial data to UTM. First, this
>>> instruction works OK:
>>> >
>>> > SELECT ST_Transform(ST_GeomFromText('POINT(0.0 20)',4326),22171) from
>>> mypoints
>>> >
>>> > No matter if such a sentence has no meaning on what I tryin to do.  But
>>> when I did the same with my own points:
>>> >
>>> > SELECT ST_Transform(mypoints.the_geom,22171) from mypoints
>>> >
>>> > I get the following error:
>>> > ERROR: Input geometry has unknown (-1) SRID
>>> > SQL state: XX000
>>> >
>>> > Ok, when I insert my points in my spatial enabled database I used:
>>> >
>>> > INSERT INTO mydistance ( the_geom, the_name ) VALUES (
>>> ST_GeomFromText('POINT(-58.0 0.0)'), 'Punto 1-1');
>>> >
>>> > without no spatial reference system explicit so I guess the SRID is set
>>> to "unknown" i.e. -1.  Then naively I created a new column named srid for my
>>> table and put the right value of SRID for all my data which is 4326 (WGS84,
>>> sexagesimal degrees lat lon) in that column but still I get the same error.
>>> After that I created a constraint between this new srid column and the srid
>>> column from the spatial_ref_sys table but nothing happened, the error is
>>> still there.
>>> > It's important to me to solve this issue because all my spatial data
>>> was loaded from shapefiles without SRID awareness so they don't have any
>>> SRID column. I don't want to reload data changing this so I need a method to
>>> alter the tables in such a way to add this new srid column to them that is
>>> well related to the spatial context.
>>> > Thanks and regards,
>>> > Oscar
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>>
>>
>
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