On Tue, Nov 25, 2008 at 12:05:43PM -0800, Michal Migurski wrote:
> On Nov 25, 2008, at 8:34 AM, Peter S Galbraith wrote:
> > Yikes... Sorry Michal.  I guess I dropped the ball on this one.
> > As a note to myself, the FAQ
> >
> > http://trac.osgeo.org/proj/wiki/FAQ
> >
> > says:
> >
> >  After downloading and unpacking the PROJ.4 source, also download and
> >  unpack the set of datum shift files. This would be a file like
> >  ftp://ftp.remotesensing.org/pub/proj/proj-datumgrid-1.4.zip. This  
> > file
> >  should be unpacked within the proj/nad directory. Then proceed with  
> > the
> >  configuration, build and install. This will ensure that the build  
> > system
> >  knows about the grid shift files, and applies the ascii to binary
> >  preprocessing step.
> >
> > Peter
> Thank you!

As said off list, I see a couple of problems:

- Three files are binary blobs, two NTv2 and one (maybe?) NTv1. I'm not too
sure that differences in endianess are considered, it needs some checks.

- It would be better having a decent summary of data provenances of those
information. I see many GIS people are not too interested in the license
aspect of projection data (see the EPSG case) but Debian cares. Currently
I wrote something like this:

Debian Proj upstream source notes

The Debian Proj package comes with both proj4 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 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

Francesco P. Lovergine

Pkg-grass-devel mailing list

Reply via email to