Debian Proj upstream source notes
---------------------------------

The Debian proj package comes with both proj upstream and additional
datum grids (http://download.osgeo.org/proj/proj-datumgrid-1.4.zip at
the time of this file) in a single package. A note about datum grids you can
find in nad/ directory and datumshifts.shar archive is mandatory.
All those data are public domain, taken and collected from various
US/Canada, France, Switzerland and New Zealand public domain resources.

Most of them are available in ASCII form, and some use a NTv2 binary 
format. The NTv2 format is a documented format used by some tools freely
available by various sources: some of them are binary-only, other
are available in source form. As references about data origins consider
the following:

Australia: http://www.icsm.gov.au/icsm/gda/gdatm/index.html
France: http://www.stjohnspoint.co.uk/gis/france.htm
Canada: http://www.geod.nrcan.gc.ca/tools-outils/ntv2_e.php
Germany: http://crs.bkg.bund.de/crseu/crs/descrtrans/BeTA/de_dhdn2etrs_beta.php
UK: http://lists.maptools.org/pipermail/proj/2006-November/002658.html
New Zealand: http://www.linz.govt.nz/geodetic/software-downloads/index.aspx
Switzerland: http://www.swisstopo.admin.ch/internet/swisstopo/en/home/products/software/products/chenyx06.html

-- Francesco Paolo Lovergine <frankie@debian.org>  Wed Nov 26 10:52:29 CET 2008

Since proj (4.9.0~rc2-1~exp1) datumgrids.shar has been using the "CTable2"
format grid shift files that aren't system dependent, but require PROJ 4.8.0
or newer. The files are available upstream in proj-datumgrid-1.6RC1.zip.

datumgrids-ch.shar was also updated to include the latest Swiss CHENyx06
dataset, adding CHENYX06a.{asc,gsb} and CHENYX06_etrs.{asc,gsb}. Those files
were downloaded from https://shop.swisstopo.admin.ch/en/products/geo_software/GIS_info

CHENYX06a.{asc,gsb} were provided by the 'NTv2 grid CH1903/LV03 -> CH1903+/LV95'
download: http://geodesy.geo.admin.ch/shop/files/chenyx06_ntv2.zip

CHENYX06_etrs.{asc,gsb} were provided by the 'NTv2 grid CH1903/LV03 -> ETRF93/ETRS89'
download: http://geodesy.geo.admin.ch/shop/files/chenyx06_etrs_ntv2.zip

-- Bas Couwenberg <sebastic@debian.org>  Sat, 03 Sep 2016 10:29:12 +0200
