Re: [DebianGIS] Fw: Re: [Proj] NAD27 and WGS84 woes
Francesco:
> ntf_r93.gsb: data
> ntv1_can.dat: data
> nzgd2kgrid0005.gsb: data
>
> Three files are in binary format: the .gsb files are NTv2 binaries,
> the other not (maybe NTv1?)
from its filename, apparently the Canadian file is NTv1 format.
> I wonder if those files are managed correctly by proj on all archs.
there has never been a complaint I know of through all the years of
PPC Mac OSX, so I would say there is no issue there. The endianness
issue I spoke of before was WRT how the USA ascii files are processed
to binary by GRASS. This was a grass bug from long long ago, so forget
I mentioned it.
> I found a reference to NTv2 formats,
http://www.geod.nrcan.gc.ca/tools-outils/ntv2_e.php
"The software is generically written for DOS, and the supplied FORTRAN source code can easily be recompiled by the end-user to modify the formats for the input and output coordinate data, or to port the NTv2 to other platforms such as UNIX, VAX/VMS, and MAC/OS. Complete grid shift file structure specifications and access algorithms facilitate more complex integration into end-user systems."
> but not for the second file. Do you have more information about that?
the NTv1 format?
Francesco email #2:
> As explained in the related bug report, I'm afraid that those blobs
> are not endianess-safe.
what bug report is that?
I believe that they are endian safe. To resolve that we'd need to look
in the PDF spec in the above .gc.ca URL.
> The NTv2 binary has an ASCII counterpart, so it is probably better
> pre-convert them in ASCII format.
you could say the same for RGB bitmaps in common image formats.
To me that's a waste of time and risks introducing unintended changes
for no gain.
I don't see any problem with the binary NTv[12] files. The format is
publicly documented in PDF, fortran code exists on the Canadian site
to work with them.
> Do you have a reference for the NTv1 format?
I don't, but it'll surely be out there somewhere and can be found before
submitting the package. Natural Resources Canada personel are active in
the FOSS world and should be able to help.
> Also, it's better avoiding binary blobs, which are always looked
> with suspect by ftpmasters.
again, for a documented binary format with code it's really not much
different than a RGB bitmap image. Undocumented binary blobs are
questionable, documented ones are without question as long as links to
the format documents are provided in a README.
> A general problem anyway is about a missing accompanying license for
> those files.
Debian rules state that anything going into Debian has to come with
a license documentation. This should not be so hard to arrange,
of the 15 files:
----------------
The 12 USA ones are sourced from the 1993 release of PROJ4 by Gerald
Evenden when he worked at the USGS. Gerald remains the maintainer of
libproj to this day and can be found on the proj mailing list if needed.
see ftp://ftp.remotesensing.org/proj/from_kai/ for historic release notes.
or just download his current MIT/X libproj and go from there.
The NTv1 Canada file I don't know about; someone else will.
Natural Resources Canada personel are active in the FOSS world
and should have access to it.
Permission to use the French grid file (ntf_r93) is in the proj mailing
list archives, URL in my prev email.
Permission to use the New Zealand grid file (ntf_r93) is in the proj
and grass mailing list archives. I have the original correspondence.
> People say they are public domain, but there's no evidence about that.
see above.
> There are many places where they are distributed, but this is does not
> imply they are public domain...
except if one of those places is the USGS and the rest have documentation
from their source.
As "Public Domain" has a specific legal meaning, I do not think it is
right to apply that term to the non-US data. Better to say the given
consent is compatible with the DFSG and provide the words given.
Frank:
> Nevertheless, if the position of the Debian project is that they don't
> trust the license status of these files,
the position of the Debian project (which is the DFSG text) is that they
need *a* license file with any package they are to redistribute.
And proj-datumgrid-1.4.tar.gz only has data in it.
A license file in a separate .tar.gz in the same FTP dir isn't good enough
because it is for something else.
I believe that the READMEs in the proj ftp site "from_kai" dir may suffice
for the US data though.
regards,
Hamish
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