RES: [postgis-users] User Friendly vs Explicit

[Bart van den Eijnden]

The EPSG database already has Access forms inside it for finding SRS  
codes. AFAIK PostGIS SRID is the same code as the EPSG code.

http://www.epsg.org/

Also, I usually search the epsg text file distributed with PROJ 4 to find  
an SRS code.

Best regards,
Bart

On Mon, 16 May 2005 21:02:37 +0200, Mike Leahy <mgleahy at fes.uwaterloo.ca>  
wrote:

> I'm just wondering if there is a listing anywhere that makes it
> relatively easy to look-up SRIDs.  In the spatial_ref_sys table there
> are over 2600 records, and after a bit of searching around, I've found
> that if somebody wanted to find the the appropriate SRID for a
> particular projection in PostGIS the only way to find it (that I can
> see) is to search through this table in PostGIS/PostgreSQL.  Maybe it
> would be useful to make a more readable document, or maybe a web-page
> somewhere that allows users to browse the spatial_ref_sys table in a
> more user-friendly way, or perhaps such a thing already exists and I
> just don't know what to look for.
>
> Mike
>
> Gustavo Henrique Sberze Ribas wrote:
>
>>  Some links about projections and the Earth:
>>
>>
>> The Earth:
>> http://www.gfz-potsdam.de/news/foto/images/GFZ-Potsdam-PR-20030122-Geoid-Undulation-1250x1250.jpg
>>
>> How to map the Earth:
>> http://kartoweb.itc.nl/geometrics/Reference%20surfaces/body.htm
>> http://exchange.manifold.net/manifold/manuals/5_userman/mfd50The_Earth_as_an_Ellipsoid.htm
>> http://solid_earth.ou.edu/notes/geoid/earths_geoid.htm
>>
>> Map Projections:
>> http://www.fes.uwaterloo.ca/crs/geog165/mapproj.htm
>>
>> Check the Data Standards section:
>> http://maic.jmu.edu/sic/topics.htm
>>
>>
>>
>> --
>> Gustavo
>>
>>
>> -----Mensagem original-----
>> De: postgis-users-bounces at postgis.refractions.net  
>> [mailto:postgis-users-bounces at postgis.refractions.net]Em nome de Mark  
>> Fenbers
>> Enviada em: sábado, 14 de maio de 2005 20:17
>> Para: PostGIS Users Discussion
>> Assunto: Re: [postgis-users] User Friendly vs Explicit
>>
>>
>> Mark Fenbers wrote:
>> Norman Vine wrote:
>> This is commonly referred to as the Vornoi Diagram
>> http://www.cs.cornell.edu/Info/People/chew/Delaunay.html
>>
>> program that can compute this for you
>> http://www-2.cs.cmu.edu/~quake/triangle.html
>>
>>
>> Wow!  I never knew this had a name!  Your info was interesting and  
>> helpful, but I want to calculate Voronoi Diagrams using PostGIS so that  
>> all I have to pass around is some SQL to each site having different  
>> radars to work with...  I have yet to find documentation that makes it  
>> clear to me why SRIDs (other than -1) are useful, and how to reproject  
>> lat/lons into a planar projection.  I see that the distance() function  
>> also needs reprojected data to be useful...
>>
>>
>> OK, well, reading through more documentation and online stuff, I  
>> learned of a spatial_ref_sys.sql file that wasn't run during  
>> installation.  So now I have the spatial_ref_sys table populated and  
>> now understand that SRID relates to different map projections.  But  
>> this brings up even more questions, like "How in the world  
>> (figuratively) will I be able to pick an SRID that's right for the work  
>> I am doing?"  And is the use of SetSRID() what actually reprojects my  
>> data?
>>
>> Mark
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>>
>>
>>
>
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