[postgis-users] PostGIS Transform and Quantum GIS

[cyw at dls.net]

Thanks. That's exactly the problem.
CYW

----- Original Message ----- 
From: "Obe, Regina" <robe.dnd at cityofboston.gov>
To: "PostGIS Users Discussion" <postgis-users at postgis.refractions.net>
Sent: Friday, October 10, 2008 10:27 AM
Subject: RE: [postgis-users] PostGIS Transform and Quantum GIS


Geometry_Columns is a table that contains the listing of table geometry
columns.
It gets autofilled when you do AddGeometryColumn to add a geometry
column.

So as Paul said you will need to manually correct the table because
Quantum is probably reading it as a faster way of determining the SRID.

 

-----Original Message-----
From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of
cyw at dls.net
Sent: Friday, October 10, 2008 11:18 AM
To: PostGIS Users Discussion
Subject: Re: [postgis-users] PostGIS Transform and Quantum GIS

Thanks, Paul.

1. What do you mean by  GEOMETRY_COLUMNS ? Do you mean the 'geometry' 
column?

I did "select srid(the_geom) from city limit 10" on the transformed
table, 
it retured '26971'.

2.  I tried to display the transformed table with new QuantumGIS project

(new db connect, add, ...). I actually just did upgrade to the newest
Dev 
version of QuantumGIS. Still the same.


CYW


----- Original Message ----- 
From: "Paul Ramsey" <pramsey at cleverelephant.ca>
To: "PostGIS Users Discussion" <postgis-users at postgis.refractions.net>
Sent: Friday, October 10, 2008 9:58 AM
Subject: Re: [postgis-users] PostGIS Transform and Quantum GIS


> Try removing the table from qgis and re-adding it. And don't forget to
> change the SRID value in GEOMETRY_COLUMNS before you do. I think
> you're altering the coordinates underneath QGIS's understanding of
> that they are (it things it has a 4326 table, and boom, you turn it
> into something else).
>
> P.
>
> On Fri, Oct 10, 2008 at 7:16 AM,  <cyw at dls.net> wrote:
>> Just wonder if anyone had similar experience.
>>
>> I have a table with multipolygons for cities (in latitude/longitude,
>> srid=4326), I could display it with QuantumGIS.
>>
>> Then I did a transform to a plane coordinate system, and verified the

>> result
>> (astext(the_geom)) and saw  no problem.
>>
>> Then I tried to view it again with QuantumGIS. Though no error
message,
>> nothing could be display. After zoom-to-layer, the cursor coordinate 
>> values
>> were consitent with the extent of the data in the projected
coordinate
>> system.
>>
>> Below are the SQL command I did:
>>
>> ALTER TABLE city DROP CONSTRAINT enforce_srid_the_geom;
>> update city set the_geom=transform(the_geom,26971)  where
>> polygon_id=35665106;
>> alter table city add CONSTRAINT enforce_srid_the_geom CHECK 
>> (srid(the_geom)
>> = 26971);
>>
>> Thanks,
>> CYW
>>
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