[postgis-users] Re: srid / area

[Christo Du Preez]

Hi Patrick,

Yes, I'm quite sure my data is in decimal degrees.

I ran [select UpdateGeometrySRID('public', 'cdsmriverarea', 'the_geom', 
4148);] on my data. I did notice if you look below that there is no 
units specified at the end. So I tried using transform with srid 2046, 
which does specify units=m. And I'm still getting the same result.

4148;"EPSG";4148;"GEOGCS["Hartebeesthoek94",DATUM["Hartebeesthoek94",SPHEROID["WGS 

84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],TOWGS84[0,0,0,0,0,0,0],AUTHORITY["EPSG","6148"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY 

(..)";"+proj=longlat +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +no_defs "

2046;"EPSG";2046;"PROJCS["Hartebeesthoek94 /
Lo15",GEOGCS["Hartebeesthoek94",DATUM["Hartebeesthoek94",SPHEROID["WGS
84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],TOWGS84[0,0,0,0,0,0,0],AUTHORITY["EPSG","6148"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degr 

(..)";"+proj=longlat +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +units=m 
+no_defs "

Patrick wrote:
> Hi Christo,
>
> Maybe a silly question, but are you sure that your data are in decimal 
> degree and not in kilometer? That would exactly explain the order of 
> magnitude difference you indicated.
>
> Regards,
> Patrick
>
> "Christo Du Preez" <christo at mecola.com> wrote in message 
> news:4469996A.7080009 at mecola.com...
>   
>> select area(the_geom) AS ar
>> from cdsmriverareaview
>> order by ar
>>
>> 6.70955000170448e-08
>>
>> the expected result is roughly 670 sq meters. 
>>     
>
>
>
> _______________________________________________
> postgis-users mailing list
> postgis-users at postgis.refractions.net
> http://postgis.refractions.net/mailman/listinfo/postgis-users
>
>
>   

-- 
Kind Regards,
Christo Du Preez

Senior Software Engineer
Mecola IT
http://www.mecola.com
+27 [0]83 326 8087