[Proj] GeoTiff <-> Proj.4

[support.mn at elisanet.fi]

Hello,

I am still asking if it is totally not possible to use omerc to decode GeoTiff
projections 3,4 and 5. The problem seems to be wha to do with the
"rectified grid angle" ? Proj.4 does not support such angle?

"Alpha" must be the "azimuth angle"?

Frank Warmerdam <warmerdam at pobox.com> kirjoitti: 
> > WE ARE IN DESPERATE NEED OF A COMPREHENSIVE, ACCURATE
> > AND RELIABLE REFERENCE OF CARTOGRAPHIC PROJECTIONS.
> 
> I would love for such a thing to exist in a form that can be easily related
> to various software systems and file formats. I would love to see such
> an effort attacked as a "MetaCRS" effort - that is collaboratively amoung
> the various experts here, the CS-Map community and some of the other
> OSGeo coordinate system efforts (ie. GeoTools).

Someone just have to send a message to the ANSI and ask them to fix
the problem with the terminology.

http://en.wikipedia.org/wiki/American_National_Standards_Institute

More about Geotiff <-> Proj.4:

Ref 1:
http://www.remotesensing.org/geotiff/proj_list/lambert_conic_conformal_2sp.html

Ref 2:
http://www.remotesensing.org/geotiff/spec/geotiff3.html#3.1.3.

Ref 1 gives:

+proj=lcc
              +lat_1=Latitude of first standard parallel
              +lat_2=Latitude of second standard parallel
              +lat_0=Latitude of false origin 
              +lon_0=Longitude of false origin
              +x_0=False Origin Easting
              +y_0=False Origin Northing

Ref 2 gives:

+proj=lcc
              +lat_1=Latitude of first standard parallel
              +lat_2=Latitude of second standard parallel
              +lat_0=Latitude of natural origin (ProjNatOriginLatGeoKey)
              +lon_0=Longitude of projection center (ProjCenterLongGeoKey)
              +x_0=False Origin Easting
              +y_0=False Origin Northing

I am starting to belive that best way to deal with the problem is to first allocate
lat_1, lat2, lat_ts and then start to look after any lat or lon and put them
to lat_0 and lon_0. Since every creator of GeoTiff files puts them randomly
somwhere what is left.

Regards Janne.