[Proj] GeoTiff <-> Proj.4

[support.mn at elisanet.fi]

"Gerald I. Evenden" <geraldi.evenden at gmail.com> kirjoitti: 
> On Friday 03 October 2008 11:25:47 am support.mn at elisanet.fi wrote:
> > 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
> 	...
> > http://en.wikipedia.org/wiki/American_National_Standards_Institute
> 
> I first thought was: "what a good idea," but skimming on to ISO reference the 
> criticism section brought up the cost involved and that reminded me of a long 
> ago experience.  I thought it would be a good idea to get a copy of the ANSI 
> C standards but suddenly ran into the $$$  for a copy.
> 

If not ANSI, why not CEN?

http://www.cen.eu/cenorm/homepage.htm

"CEN, the European Committee for Standardization, was founded in 1961 by the
national standards bodies in the European Economic Community and EFTA countries."

> > 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
> 
> They should really be called the secant parallels.  There is 
> nothing "standard" about them.
> 
> The alternate lcc is to specify the parallel of tangency and then k_0 which 
> does the same thing.
> 
> >               +lat_0=Latitude of false origin
> >               +lon_0=Longitude of false origin
> 
> Oh, please! "of false origin" good grief.
> 
> >               +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
> 
> Terrible, terrible.  Proj may have also been guilty of the "standard" part.
> 
> > 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.
> 
> lat_ts is not involved with conics.
> 

Yes, I was more thinking a general method to connect parameters regardless
of the specific projection.

> Is there an editor or editing group associated with these sites?

I don't know, LibGeoTiff or remotesensing?

Janne.