[postgis-users] Re: SRS WKT >>> srid?

Paul Ramsey pramsey at refractions.net
Wed Oct 19 08:28:32 PDT 2005


Patrick,
True enough indeed!
Paul

On Oct 19, 2005, at 8:36 AM, Patrick wrote:

>
> On 19-Oct-2005, Paul Ramsey <pramsey at refractions.net> ever so  
> gracefully
> noted:
>
>
>
>> Generally, with some simple string comparisons and your eyes.
>>
>
>
>> No, it's not very efficient, but it is the standard, so it's not
>> going anywhere.  If you need a nice normalized source of CRS
>> information, the EPSG database from which our spatial_ref_sys
>> contents are derived is the place to go.  Just google EPSG.
>>
>
> Paul,
>
> I know EPSG and I know it's normalized and it doesn't make any  
> sense sending
> me or anybody else there because everybody here wants to use  
> PostGIS. And
> string comparisons may be simple, but they are not efficient on  
> about 4MB of
> strings. I'll skip the thingy on my eyes, if you don't mind.
>
> Insofar as standards go, OGC is an interoperability standard and it  
> does not
> prescribe any particular underlying format. It would be very valid  
> to have
> all the CRS information in a number of base tables and then a  
> single view
> that implements the OGC spatial_ref_sys table and which draws its
> information from the base tables, assembling it into WKT using some
> function. That would allow savvy programmers to efficiently query  
> the CRS
> components while still providing for the discovery and cataloguing  
> services
> that OGC mandates.
>
> It would take quite some work to implement such an arrangement, but  
> it would
> most definitely not break any existing application code, as  
> spatial_ref_sys
> would not be expressed differently.
>
> Just a thought,
> Patrick
>
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