
Hi Folks,

I am trying to fully integrate GRASS database support into the PCI software
product, and I am somewhat confused about projections support.  I am basing
my work on the GRASS 4.0 Programmer's Manual (DRAFT) dated August 11, 1992.
I am primarily utilizing the chapter on ``Database Structure'' which 
defines the directory tree, and file formats within it.

Recently I have discovered that some of our customers using GRASS have raster
layers with a ``proj'' code of 99 in the ``cellhd'' files, and projection
information in a file called PROJ_INFO in the PERMANENT directory.  The
following is an example of one of these files:

name: Albers Equal Area
proj: aea
ellps: aust_ntl
a: 6378160.0000000000
es: 0.0066945419
lat_0: -25.0000000000
lon_0: 135.0000000000
lat_1: -25.0000000000

I have a few questions for the list:
 o Does use of projection information post-date V4.0?
 o Where can I get upto date documenation?  Does this include a listing
   of all supported projections?
 o Is the use of PROJ_INFO files common with GRASS?

My intention is to properly import projection information into EASI/PACE,
and to export EASI/PACE projection information to GRASS to the extent that
is possible.

While I have everyone's ear, is the following cellhd file legitimate?
Are GRASS applications expected to handle the `n', `s', `e' and `w'
modifiers for long/lat regions?  What does a resolution of `1:00000' mean?
Is this type of header information a post 4.0 development?  

proj:       3
zone:       0
north:       90n
south:       90s
west:        180w
east:        180e
n-s resol:  1:000000
e-w resol:  1:000000
format:     0
compressed: 1

Thanks for your attention and patience,

-------------------------------------------------------------------------------
Frank Warmerdam | Who can give them back their lives | warmerda@pci.on.ca    
Software Artist | and all those wasted years? - Rush | 

