• GeoDLL - Geodetic function collection
•  Brief Description of the Current Version
•  Development Tool Description
•  Specification Function coordtrans3d() as example
•  List of coordinate and reference systems
•  NTv2 Support with GeoDLL
•  Useage of Digital Elevation Models with GeoDLL
•  Screenshots
•  Download GeoDLL test version
•  Prices GeoDLL full version
•  Order GeoDLL full version

GeoDLL - Support of the NTv2 standard
 Directly to the chapter "Download of the NTv2 grid files in binary format"

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.

Coordinate transformations with the BeTA2007 test data of the ADV

The program TRANSDAT and the function libraries GeoDLL and BetaDLL supports NTv2 standard coordinate transformations with high accuracy. Amongst others the NTv2 grid file BeTA2007 can be used for transformations within Germany with results in sub-meter accuracy. The grid file is provided by the "Arbeitsgemeinschaft der Vermessungsverwaltungen der Länder der Bundesrepublik Deutschland" (ADV), along with a documentation and a set of test data. The test data contain 31 spaced points on the territory of the Federal Republic of Germany in different variations with coordinates in both reference systems DHDN90 and ETRS89.

Comparative calculations with the test data of the ADV, done by the engineering office C. Killet Software Ing.-GbR, attest to the software TRANSDAT, GeoDLL and BetaDLL a very good self-consistency. Here are the results:

1. Forward calculation Gauss-Krueger / DHDN90 to UTM / ETRS89:
   Maximum deviation 0,04 millimeters
   Average deviation 0,02 millimeters
2. Forward calculation Geographic Coordinates DHDN90 to ETRS89:
   Maximum deviation 0,51 microseconds (millionth seconds), that corresponds appr. 0,01 millimeters
   Average deviation 0,19 microseconds
3. Reverse calculation UTM / ETRS89 to Gauss-Krueger / DHDN90 on different meridian strips:
   Maximum deviation 0,20 millimeters
   Average deviation 0,07 millimeters
4. Reverse calculation Geographic Coordinates ETRS89 to DHDN90:
   Maximum deviation 0,51 microseconds
   Average deviation 0,18 microseconds

You can download the  test protocol and the tables with the corresponding calculations from our server.

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.

For some NTv2 files, downloadable from this site, exists special usage permissions. These files are encrypted and can only be used by the KilletSoft products TRANSDAT and GeoDLL, which contain the decrypt mechanism. These files are special licensed to KilletSoft by their copyright owners.

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. Austria: AT_GIS_GRID.gsb, MGI <==> ETRS89
   Original data:  BEV - Bundesamt für Eich- und Vermessungswesen.
   KilletSoft:  Download AT_GIS_GRID
4. Canada: NTV2_0.gsb, NAD27 <==> NAD83
   Original data:  Natural Resources Canada: Canadian Spatial Reference System - NTv2.
   KilletSoft:  Download NTV2_0
5. France: NTF_R93.gsb, NTF <==> RGF93
   Original data:  IGN (Institut Géographique National): Projet "Lambert 93".
   KilletSoft:  Download NTF_R93
6. France: FRANCE.gsb, NTF <==> RGF93
   Original data:  Paul Kelly: Creation of NTv2 Grid File for France.
   KilletSoft:  Download FRANCE
7. Germany: BeTA2007.gsb, DHDN90 <==> ETRS89
   Original data:  Bundesamt für Kartographie und Geodäsie.
   KilletSoft:  Download BeTA2007
8. Germany (Hesse): HeTA2010.gsb, DHDN90 <==> ETRS89
   Original data:  HVBG - Hessische Verwaltung für Bodenmanagement und Geoinformation.
   KilletSoft:  Download HeTA2010 (© HVBG)
   Usuage permission: The here available NTv2 file HeTA2010.gsb from "Hessische Verwaltung für Bodenmanagement und Geoinformation" of the Federal State of Hesse is encrypted and can only be used by the KilletSoft products TRANSDAT and GeoDLL!
9. Germany (Saxony): SaeTA2010.gsb, RD83 <==> ETRS89
   Original data:  GeoSN - Landesvermessung Sachsen.
   KilletSoft:  Download SaeTA2010 (© GeoSN)
   Usuage permission: The here available NTv2 file SaeTA2010.gsb from "GeoSN - Landesvermessung Sachsen" of the Federal State of Saxony is encrypted and can only be used by the KilletSoft products TRANSDAT and GeoDLL!
10. Germany (Thuringia): NTv2GridTh.gsb, PD83 <==> ETRS89
    Original data:  TLVermGEO - Landesamt für Vermessung und Geoinformation - Thüringen.
    KilletSoft:  Download NTv2GridTh (© TLVermGEO)
    Usuage permission: The here available NTv2 file NTv2GridTh.gsb from the "Landesamt für Vermessung und Geoinformation" of the Federal State of Thuringia is encrypted and can only be used by the KilletSoft products TRANSDAT and GeoDLL!
11. Great Britain: ENGLAND.gsb, OSGB36 <==> ETRS89
    Original data:  Paul Kelly: OSTN02 in NTv2 format for OSGB36<-->ETRS89.
    KilletSoft:  Download ENGLAND
12. Great Britain: SCOTLAND.gsb, OSGB36 <==> ETRS89
    Original data:  Paul Kelly: OSTN02 in NTv2 format for OSGB36<-->ETRS89.
    KilletSoft:  Download SCOTLAND
13. New Zealand: NZGD2KGR.gsb, NZGD49 <==> NZGD2000
    Original data:  Land Information New Zealand: Download Geodetic Software.
    KilletSoft:  Download NZGD2KGR
14. Portugal: PT73_E89.gsb, D73 <==> ETRS89
    Original data:  A vida de um Informático.
    KilletSoft:  Download PT73_E89
15. Portugal: PTLX_E89.gsb, DLX <==> ETRS89
    Original data:  A vida de um Informático.
    KilletSoft:  Download PTLX_E89
16. Portugal: PTBL_E89.gsb, B-DLX <==> ETRS89
    Original data:  A vida de um Informático.
    KilletSoft:  Download PTBL_E89
17. Portugal: PTED_E89.gsb, ED50 <==> ETRS89
    Original data:  A vida de um Informático.
    KilletSoft:  Download PTED_E89
18. Spain (Peninsula 2009): PENR2009.gsb (=R2009V2.gsb), ED50 <==> ETRS89
    Original data:  Instituto Geografico Nacional - Ministerio de Fomento.
    KilletSoft:  Download PENR2009
19. Spain (Baleares 2009): BALR2009.gsb, ED50 <==> ETRS89
    Original data:  Instituto Geografico Nacional - Ministerio de Fomento.
    KilletSoft:  Download BALR2009
20. Spain (Pen + Bal 2003): SPED2ET.gsb, ED50 <==> ETRS89
    Original data:  Instituto Geografico Nacional - Ministerio de Fomento.
    KilletSoft:  Download SPED2ET
21. Switzerland: CHENYX06.gsb, CH1903 <==> CH1903+
    Original data:  Bundesamt für Landestopographie swisstopo: CHENyx06.
    KilletSoft:  Download CHENYX06

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