[Proj] Knowing projection from bounding box values.

Mikael Rittri Mikael.Rittri at carmenta.com
Fri Sep 23 05:58:30 EST 2011


Hello Mustafa,

> If bounding box values are given, then can we determin the projection ?

The short answer is no.

> Bounding Box (Min X, Max X) = 161691.814, 161835.595 Bounding Box (Min Y, Max Y) = 6581562.789, 6581647.802

But if we assume the projection is Transverse Mercator in meters,
with origin at the equator, then the bounding box would be roughly 
at latitude 59d20' N, which is the latitude of Stockholm.

Since you have asked about the Stockholm area before, 
this suggests a CRS for Sweden (perhaps you already knew that).
The Swedish projections based on the old RT90 datum would
have seven-digits easting, so they are ruled out. 
   
I think the projection is based on the new datum SWEREF99,
but it cannot be the national SWEREF99 TM, because the 
bounding box would then be somewhere in Norway, I think.

But I think it is the regional projection SWEREF99 18 00.
http://www.lantmateriet.se/templates/LMV_Page.aspx?id=4219&lang=EN
It has central meridian at 18d E and false easting = 150 000 m,
so your bounding box would be about 12 km east of meridian 18d E,
(and at latitude 59d20' N).  That's Stockholm, isn't it? 

Or maybe it is a projection based on ST74.

Best regards,

Mikael Rittri
Carmenta 
Sweden
http://www.carmenta.com

-----Original Message-----
From: proj-bounces at lists.maptools.org [mailto:proj-bounces at lists.maptools.org] On Behalf Of Mustafa646
Sent: den 20 september 2011 15:45
To: proj at lists.maptools.org
Subject: [Proj] Knowing projection from bounding box values.

If bounding box values are given, then can we determin the projection ?

let say i have following bounding box values:

Bounding Box (Min X, Max X) = 161691.814, 161835.595 Bounding Box (Min Y, Max Y) = 6581562.789, 6581647.802

then, what will be the projection file or EPSG code ?

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