[postgis-users] Coordinate Transformation using theLongitude_Rotation math transform function

[strk at refractions.net]

On Mon, Feb 14, 2005 at 11:46:18PM +1300, Bryce Watkins wrote:
> My apologies - I should have included more info - this is the contents of
> proj4text field:
> +proj=longlat +ellps=GRS80
> 
> Also output of postgis_full_version():
> "POSTGIS="0.9.0" PROJ="Rel. 4.4.9, 29 Oct 2004" USE_STATS DBPROC="0.0.1"
> RELPROC="0.0.1""

mmm... unfortunately 0.9 did not have any meaningful error message
in case of failure. You could try upgrading to 1.0.0RC2 and see
what happens (if you get a NULL result).

If you get a *wrong* result I suspect PROJ4 changed semantic of some
fields.

--strk;

> 
> Cheers,
> Bryce.
> 
> -----Original Message-----
> From: postgis-users-bounces at postgis.refractions.net
> [mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of
> strk at refractions.net
> Sent: Monday, 14 February 2005 9:40 p.m.
> To: postgis-users at postgis.refractions.net
> Subject: Re: [postgis-users] Coordinate Transformation using
> theLongitude_Rotation math transform function
> 
> On Mon, Feb 14, 2005 at 08:58:54PM +1300, Bryce Watkins wrote:
> > Hi folks - has anyone tried this, and or am I even heading in the 
> > right direction here?
> >  
> > The problem is that we have a dataset that has been longitude geometry 
> > shifted by 160 degrees to get around the problem of trying to project 
> > geometries either side of 180 degree longitude where they exist in the 
> > same SRID.
> > We want to see this data in the correct format, so I have created an 
> > SRID that uses a FITTED_CS and a PARAM_MT to try to compensate (as shown
> below).
> > I have gotten most of this info from the OpenGIS Implementation
> > Specification: Coordinate Transformation Services document on the 
> > OpenGIS website.  However this doesn't appear to work and am wondering 
> > if somebody can shed some light on the problem.
> >  
> > Thanks in advance,
> > Bryce.
> 
> Postgis requires the proj4text field to be filled.
> --strk;
> 
> >  
> > srtext field in spatial_ref_sys:
> > FITTED_CS["FM_MOD", PARAM_MT["Longitude_Rotation", PARAMETER["dim", 
> > "2"], PARAMETER["rotation", "160"]],
> > GEOGCS["GCS_NZGD_2000",DATUM["D_NZGD_2000",SPHEROID["GRS_1980",6378137
> > ,298.2 
> > 57222101]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]]]
> 
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