• TRANSDAT - World-wide coordinate transformations
•  Brief Description of the Current Version
•  Program Description
•  Coordinate and Reference Systems - Overview
•  List of Coordinate and Reference Systems
•  NTv2 support
•  Screenshots
•  Download TRANSDAT
•  Prices TRANSDAT
•  Order TRANSDAT

TRANSDAT - Support of the NTv2 standard

NTv2 means "National Transformation Version 2". The NTv2 method uses binary files to perform accurate datum shifts from one geodetic reference system to an other. A NTv2 file contains the differences between the two reference systems as geographic seconds in a grid. A bilinear interpolation is used to calculate the exact coordinates for a point in the target reference system.

NTv2 is designed to check multiple grids for the most accurate shift information. A NTv2 file contains a low density base grid (parent). Certain areas such as cities can have high density local sub grids. The sub grids overlay portions of the base grid. If a point is within one of the high density sub grids, NTv2 will use the high density grid, otherwise, the point falls through to the low density grid.

A description of the NTv2 algorithm can be found in the following sources:

1. Junkins, D.R., and S.A. Farley, NTv2 Developers Guide; Geodetic Survey Division, Natural Resources Canada, 1995.
2. Junkins, D.R., and S.A. Farley, NTv2 Users Guide; Geodetic Survey Division, Natural Resources Canada, 1995.
3. Werner Flacke, ESRI Geoinformatik GmbH,  NTv2 für Deutschland, 2006.

Download of the NTv2 grid files in binary format

Here the NTv2 binary files are listed, which are supported by the geodetic Library GeoDLL and the program TRANSDAT. In the second line always the original source is shown, from which the original NTv2 file can be downloaded and information about the associated geodetic reference systems are given. In the third line is a link, from which the NTv2 file can be download direct from the KilletSoft server. It is recommended to use the original NTv2 files from the original sources, because the actuality of the files stored on the KilletSoft server is not guaranteed.
 
Important note:
If you want to use the here listed NTv2 files, you must necessarily note the terms and conditions of their authors! All rights and liabilities, resulting from the use of the data, bears solely the user! KilletSoft does not guarantee the accuracy of the data!

1. Australia: A66_NAT.gsb, AGD66 <==> GDA94
   Original data:  Intergovernmental Committee on Surveying & Mapping.
   KilletSoft:  Download A66_NAT
2. Australia: A84_NAT.gsb, AGD84 <==> GDA94
   Original data:  Intergovernmental Committee on Surveying & Mapping.
   KilletSoft:  Download A84_NAT
3. Canada: NTV2_0.gsb, NAD27 <==> NAD83
   Original data:  Natural Resources Canada: Canadian Spatial Reference System - NTv2.
   KilletSoft:  Download NTV2_0
4. France: FRANCE.gsb, NTF <==> RGF93
   Original data:  Paul Kelly: Creation of NTv2 Grid File for France.
   KilletSoft:  Download FRANCE
5. Germany: BeTA2007.gsb, DHDN90 <==> ETRS89
   Original data:  Bundesamt für Kartographie und Geodäsie.
   KilletSoft:  Download BeTA2007
6. Great Britain: ENGLAND.gsb, OSGB36 <==> ETRS89
   Original data:  Paul Kelly: OSTN02 in NTv2 format for OSGB36<-->ETRS89.
   KilletSoft:  Download ENGLAND
7. Great Britain: SCOTLAND.gsb, OSGB36 <==> ETRS89
   Original data:  Paul Kelly: OSTN02 in NTv2 format for OSGB36<-->ETRS89.
   KilletSoft:  Download SCOTLAND
8. New Zealand: NZGD2KGR.gsb, NZGD49 <==> NZGD2000
   Original data:  Land Information New Zealand: GD2000it Download.
   KilletSoft:  Download NZGD2KGR

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