[Geotiff] proj4 support question and bug?

[brownrigg at sunflower.com]

A question and a bug(?):

Q: While it appears there's support for specifying projections in libgeotiff using proj4-style strings, I was recently surprised and disappointed to find that there's only a rather small set of projections actually supported. Browsing the code in "geotiff_proj4.c", it looks like much code was lifted from OGR, but is commented out, presumably because it makes use of OGR API functions not available in libgeotiff (?)  Can someone comment on what is required to implement broader proj4 projection support in libgeotiff?  It is simply a matter of following the patterns set out for the current projections (i.e., set as approp. GMModelTypeGeoKey, ProjectedCSTypeGeoKey, ProjectionGeoKey, ProjCoordTransGeoKey, plus additional projection-specific tags)?

Bug: In geotiff_proj4.c, v1.2.5, around lines 395 -- 429, there are two cases for Lambert Conformal (lcc) that are identical conditionals.  They appear to be intended to handle the 1 vs. 2 standard parallel cases. I believe in the  2nd conditional, at line 427, should read lat_0 != lat_1,  not lat_0 == lat_1 (?).

FWIW...
Rick Brownrigg