[postgis-users] Area and scale completely wrong

[strk at refractions.net]

Does the area computation give acceptable value for the geometry's
envelope ?  [ select area(envelope(the_geom)) ] ?
Is the geometry valid ?  [ select isvalid(the_geom) ] ?

--strk;

On Mon, Nov 14, 2005 at 07:50:10PM +1100, Johan Wehtje wrote:
> I am using Postgis 1.0.4 on Win XP with Postgresql 8.1.
> 
> I had some Shape files that have Land Parcels , they use GDA94 Zone 56 (
> srid 28356) , and I used shp2pgsql to load them into my DB.
> 
> But when I an area calculation I get results that are completely wrong , and
> when i add a Postgis layer using QGIS the scale would have me beleive that
> the entire shire (which about 80 km accross) is about 2 cm.
> 
> I have tried this about twenty times, on 2 different machines - and the
> results are the same. i have verified the original shape files in Arcview,
> and when they are laoded the scale and area are all what they should be.
> 
> What am I doing wrong?
> 
> Johan Wehtje

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