[postgis-users] Define spatial reference system for local datum

[tommy408]

Thank you for your help Sean and Ralf.

When I load polygon table with srid of -1, Udig keeps saying undefined
spatial reference...unexpected behavior might occur...etc.   And when I try
to edit the layer, the layer constantly flashing and Udig crashes.



Sean Fulton wrote:
> 
> I'm not sure why you want to assign it an SRS of EPSG:4326.
> 
> uDig will load and Quantum GIS will happily load and edit the layers if 
> you assign an SRID of -1.
> 
> 
>   Sean
> 
> 
> On 2009-07-01 16:36:44 -0400, tommy408 <tommytomorow at msn.com> said:
> 
>> 
>> A lot of these tools that connect to postigs db requires a srid.  I was
>> trying out Udig.  I don't need to use these tools.  I can just work with
>> shapefile and import it to postgis.
>> 
>> But what I'm worry about is if I use a defined srid like EPSG:4326 and my
>> personal map coordinates will mess up because of the projection.  The
>> world
>> I'm mapping is flat and endless, it doesn't wrap around like earth map.
>> 
>> 
>> 
>> 
>> Sean Fulton wrote:
>>> 
>>> Can you just set the SRID to -1.  What 'map design tool' are you
>>> using?
>>> 
>>> Sean
>>> 
>>> On Jun 30, 3:00 pm, tommy408 <tommytomo... at msn.com> wrote:
>>>> I'm not mapping anything on earth.  The world I'm doing is flat.  The
>>>> polygons I'm drawing over is raster image I made.  So I'm trying not to
>>>> use
>>>> any ellipsoid projection.
>>>> 
>>>> 
>>>> 
>>>> Suhr, Ralf wrote:
>>>> 
>>>>> Do not use a local system. For everything larger than 200meters you
>>>> need a
>>>>> srs definition, because you can't messure it exactly.
>>>> 
>>>>> Take a projection from your living area und shift your geometrys to
>>>>> the
>>>>> right place.
>>>> 
>>>>> -----Ursprüngliche Nachricht-----
>>>>> Von: postgis-users-boun... at postgis.refractions.net
>>>>> [mailto:postgis-users-boun... at postgis.refractions.net] Im Auftrag von
>>>>> tommy408
>>>>> Gesendet: Dienstag, 30. Juni 2009 12:26
>>>>> An: postgis-us... at postgis.refractions.net
>>>>> Betreff: [postgis-users] Define spatial reference system for local
>>>> datum
>>>> 
>>>>> I don't need special projection.  My map is a flat plane so I'm trying
>>>> to
>>>>> use local datum as my srs because a bunch of gis map design tool ask
>>>> for
>>>>> it.
>>>> 
>>>>> So I'm trying to add a new srs into postgis spatial_ref_sys table with
>>>> the
>>>>> following srstext
>>>> 
>>>>> LOCAL_CS["Non-Earth (Meter)",LOCAL_DATUM["Local
>>>>> Datum",0],UNIT["Meter",
>>>>> 1],AXIS["X",EAST],AXIS["Y",NORTH]]
>>>> 
>>>>> What do I put for proj4text?
>>>>> --
>>>>> View this message in context:
>>>>> http://www.nabble.com/Define-spatial-reference-system-for-local-datum...
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>>>> 
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