[postgis-users] I'm missing something

[Obe, Regina]

Are these big geometries?  What does 
 
SELECT ST_AsText(the_geom)
    FROM tank_lin;
 
Also just to rule out its the table you are inserting into  - does the
Union without inserting work?
 
Select   ST_Union(the_geom)
 from tank_lin;
 
 


 
 

________________________________

From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of Bob
Pawley
Sent: Tuesday, May 20, 2008 2:11 PM
To: PostGIS Users Discussion
Subject: Re: [postgis-users] I'm missing something


Hi Regina
 
It gives me three rows each with the expression "ST_MultiLineString"
with nothing else.
 
Bob

	----- Original Message ----- 
	From: Obe, Regina <mailto:robe.dnd at cityofboston.gov>  
	To: PostGIS Users Discussion
<mailto:postgis-users at postgis.refractions.net>  
	Sent: Tuesday, May 20, 2008 10:56 AM
	Subject: RE: [postgis-users] I'm missing something

	Bob,
	 
	Strange. I don't think I have ever seen quite that error before.
What does
	 
	SELECT ST_GeometryType(the_geom)
	FROM tank_lin;
	 
	give you?
	 
	Regina

________________________________

	From: postgis-users-bounces at postgis.refractions.net on behalf of
Bob Pawley
	Sent: Tue 5/20/2008 1:07 PM
	To: PostGIS Users Discussion
	Subject: Re: [postgis-users] I'm missing something
	
	

	I tried this -
	
	Insert into graphics.process_dgm(the_geom)
	 Select   ST_Union(the_geom)
	 from tank_lin;
	
	and got the error "Unknown geometry type: 0"
	
	Bob
	----- Original Message -----
	From: "Paul Ramsey" <pramsey at cleverelephant.ca>
	To: "PostGIS Users Discussion"
<postgis-users at postgis.refractions.net>
	Sent: Tuesday, May 20, 2008 9:51 AM
	Subject: Re: [postgis-users] I'm missing something
	
	
	> You don't want the GROUP BY. It is grouping the union op on
distinct
	> geometry... ie, one per row. Remove it and you'll get what you
want,
	> one output row.
	>
	> P
	>
	> On Tue, May 20, 2008 at 8:49 AM, Bob Pawley <rjpawley at shaw.ca>
wrote:
	>> Hi
	>>
	>> I am attemptijng to use the ST_Union function to collapse
three rows from
	>> a
	>> table called tank_lin into one row in table called
process_dgm.
	>>
	>> Here's what I used -
	>> Insert into graphics.process_dgm(the_geom)
	>> Select   ST_Union(the_geom)
	>> from tank_lin
	>> Group by tank_lin.the_geom;
	>>
	>> The result is three rows inserted into process_dgm, each row
appearing to
	>> be
	>> simple copies of each of the original rows.
	>> I also attempted group by another column but received error
'unknown
	>> geometry'.
	>>
	>> I also tried STR_LineMerge with similar results.
	>>
	>> What am I not considering?
	>>
	>> Bob
	>> _______________________________________________
	>> postgis-users mailing list
	>> postgis-users at postgis.refractions.net
	>> http://postgis.refractions.net/mailman/listinfo/postgis-users
	>>
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