Information on obtaining the NTv2 data ($195 Canadian per CDROM) should be directed to:
Geodetic Survey Division, 615 Booth Street, Ottawa, Ontario, Canada K1A 0E9 Attn: Client Services Tel: (613) 995-4410 Fax: (613) 995-3215If you have the NTv2 CDROM and want the PCI software to use it, you would do the following:
1.) Activate the datum code records. In the datum.txt file in the PCI home etc sub-directory (e.g. $PCIHOME/etc/datum.txt), there are four records defined for NTv2. These records are commented out at present and can be activated by removing the exclamation mark at the front of the records.
For example, change...
!"D-86","NAD27 (Canada, NTv2)","E000","Canada","ntv2_0.gsb" !"D-87","NAD83 (Canada, NTv2)","E008","Canada","ntv2_0.gsb" !"D-88","MAY76 (Canada, NTv2)","E000","Canada","may76v20.gsb" !"D-89","NAD83 (Canada, NTv2)","E008","Canada","may76v20.gsb"To...
"D-86","NAD27 (Canada, NTv2)","E000","Canada","ntv2_0.gsb" "D-87","NAD83 (Canada, NTv2)","E008","Canada","ntv2_0.gsb" "D-88","MAY76 (Canada, NTv2)","E000","Canada","may76v20.gsb" "D-89","NAD83 (Canada, NTv2)","E008","Canada","may76v20.gsb"2.) Decide where you want the NTv2 files to reside and update the file name accordingly in the four records listed above.
A simple file name (e.g. "ntv2_0.gsb") would be searched for first in the local work account. If no file was found by that name, a search is made for it in $PCIHOME/etc.
Variations of simple file names are acceptable. For example, you could put a pathname in the filename in the datum.txt records noted above. (e.g. "/usr/etc/ntv2_0.gsb" or "c:\usr\etc\ntv2_0.gsb").
Please note that although support has been added for NTv2, PCI is still in the process of obtaining accreditation from the Geodetic Survey Division in supporting the NTv2 file format.