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Re: Define spatial reference system for local datum

by tommy408 :: Rate this Message:

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...@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...@postgis.refractions.net
> > [mailto:postgis-users-boun...@postgis.refractions.net] Im Auftrag von
> > tommy408
> > Gesendet: Dienstag, 30. Juni 2009 12:26
> > An: postgis-us...@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?
> > --
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>
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>
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