Notes
-----

Gilles Clement of Global Geomatics approved this support library
for general OpenSource release six months after it was released
as part of OGDI.  This should be approximately September of 1999. 


GXF Irregularities
------------------

 o The #TRANSFORM is defined to have commas between fields, but in the
   example files it has spaces.  Treating both the same.

 o The document doesn't mention it, but it seems that the first five
   characters have to be taken as sufficient for a field name.  For 
   instance the old sample file I have has only #TITL for the title,
   while new ones have #TITLE. 

 o It seems according to the documentation that Geographic projected
   files should list "Geographic" as their projection method, but 
   samples seem to just skip the third line of the map projection
   definition.

 o Apparently geosoft files don't have to have all the map projection
   arguments listed in the document.  For instance, eltoro.gxf's LCC
   projection doesn't contain the false easting and northing.

 o I reprojected gxf_text.gxf to lat/long producing latlong.gxf.  This
   file contains a #MAP_PROJECTION of "NAD83 / UTM zone 19N" even though
   everything is in degrees.  Why?  Should it read "Geographic"?



GG GeoTIFF Irregularities
-------------------------

 o LCC_1SP seems to ignore the scale factor at natural origin parameter.
   (ProjScaleAtNatOriginGeoKey) (should be +k= in PROJ.4).

 o 1SP form of LCC doesn't seem to have an analog in PROJ.4 -- 
   I have transformed the Longitude of Natural Origin as +lon_0, and the
   scale as +k, but it isn't clear that the scale parameter is really
   used for +proj=lcc, at least according to the documentation.  
   This _isn't_ done by the GG Geotiff translator.

 o the PROJ.4 Oblique Mercator support doesn't (apparently) include
   support for an ``Angle from Rectified to Skew Grid'' though via the
   the +no_rot flag it seems possible to choose between having this
   angle be zero or -azimuth.  Currently I am just using the angle
   to decide if +no_rot should be set. 

 o The Polar Stereographic projection in GeoTIFF is translated to 
   +proj=ups, ignoring any other polar stereographic parameters.  This
   would appear to be an error.  For the time being I am translating as
   Stereographic.

 o It appears that PROJ.4's polyconic projection doesn't include support
   for the scale at the origin (presumably 1.0). 




	

