[postgis-users] srid

[Bob Pawley]

I think I have the spatial_ref_table with a couple of rows that should be 
recognized by the ST_Transform function.

However, I now get the error "Input geometry has unknown (-1) srid".

Does anyone have a thought on how to overcome this? Is this error realing 
telling me that the function still doesn't recognize the srid?

Bob




----- Original Message ----- 
From: "Andy Anderson" <aanderson at amherst.edu>
To: "PostGIS Users Discussion" <postgis-users at postgis.refractions.net>
Sent: Sunday, May 25, 2008 11:20 AM
Subject: Re: [postgis-users] srid


> SRID is an index into the table of datums/projections/coordinate  systems 
> that PostGIS maintains; the commands to create that table are  in the file 
> spatial_ref_sys.sql that comes with the distribution.
>
> If you want to build your own transformation, you could start with one  of 
> the listed INSERT statements that matches the type of projection,  and 
> change the coordinates to match your interest. Then add it to the 
> existing table with an SRID that isn't being used.
>
> By the way, the SRID is part of the EPSG standard 
> <http://en.wikipedia.org/wiki/SRID
> >, so keep that in mind for future potential conflicts.
>
> -- Andy
>
> On May 25, 2008, at 12:21 PM, Bob Pawley wrote:
>
>> Hi
>>
>> I am attempting to learn Postgis to use as a geometric tool rather  than 
>> a geographic tool.
>>
>> The function ST_Transform(geometry, integer)  seems to be  potentially 
>> quite useful.
>>
>> Apparently, the integer required is the new coordinates referenced  by 
>> the srid. Is there some way of building a spatail reference table  in 
>> which I can enter my coordinates that the ST_Transform function  will 
>> recognize. My first simplistic attempt (entering a coordinate  with an 
>> id) didn't work.
>>
>> Bob
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