Killet Software Ing.-GbR - short: KilletSoft - is a software company, which was established in the year 1991. The society is divided into the ranges "Geodetic Standard Software", "Development Tools for Geoinformatics" and "International Geodata". The focal trades of the companies supplied by KilletSoft are consulting engineers, GIS developers, Internet marketing, public utilities, logistics, telecommunications, security and public services.
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GeoDLL - Support of the NTv2 standard

GeoDLL supports the development of geodetic software by providing geodetic functions, which are put together into function groups for specific tasks. To use highly accurate coordinate transformations with NTv2 grid files in own developments a license for the additional function group "NTv2 Transformations" can be purchased. Requirement for the use of this function group is a license of the function group "Coordinate Transformations".

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. An 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. An 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. Staatsbetrieb Geobasisinformation und Vermessung Sachsen,  Geobasisinformation und Vermessung.

Download of the NTv2 gridfiles in binary format

The NTv2 grid files supported by the program TRANSDAT and the function librariy GeoDLL you can download  here from the KilletSoft website!

Accuracy check with the BeTA2007 test data of the ADV

The program TRANSDAT and the function librariy GeoDLL supports NTv2 standard Coordinate Transformations with high accuracy. Amongst others the NTv2 gridfile BeTA2007 can be used for transformations within Germany with results in sub-meter accuracy. The gridfile 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 Killet Software Ing.-GbR, attest to the software TRANSDAT and GeoDLL 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.

Accuracy check with an extreme NTv2 file of the network operator Westnetz GmbH

For a current quality analysis and in collaboration with the engineering office KilletSoft the biggest German network operator Westnetz GmbH has again conducted comparative calculations with TRANSDAT / GeoDLL. The NTv2 file used for the quality analysis has been compiled by Westnetz for the conversion of all inventory data with spatial reference. The NTv2 file allows Coordinate Transformation with cadastral accuracy on the basis of official solutions in the area of the old German federal states (without Berlin). The NTv2 file contains 64 sub and sub-sub grids with over 7 million data lines in total. For testing purposes a coordinate file with a grid of 4,328,291 points for transformations from Gauß-Krueger/DHDN90 to UTM/ETRS89 has been generated. FME (Feature Manipulation Engine by the Canadian company Save Software) was used as reference software for comparative calculations and quality assurance measures.

More than 4.3 million points were transformed with TRANSDAT / GeoDLL and the reference software from Gauß-Krueger/DHDN90 to UTM/ETRS89, and then compared afterwards. There were no deviations bigger than one millimeter. Such minor deviations (0-1mm) are tied to mathematic tolerances and internal rounding of the used software.

The  test result and statements on the speed of the calculations can be found in our publication on the Internet.

Characteristics of the additional group "NTv2 Transformations"

  1. Predefined NTv2 Reference Systems
  2. Embedding of any NTv2 gridfiles
  3. Support of Polygonal Validity Scopes in NTv2 files
  4. Use of ASCII gridfiles (.gsa) and binary gridfiles (.gsb)
  5. Automatically allocation of NTv2 files from a common directory
  6. Download of many NTv2 files from the KilletSoft website
  7. Links to NTv2 providers on the KilletSoft website
  8. HARN grid files of the U.S. supported as equivalent NTv2 grid files
  9. Free use of some NTv2 files, which otherwise are available for a fee
  10. Access to NTv2 files, which are specially licensed for KilletSoft

Functions of the additional group "NTv2 Transformations"

  1. Function getntvbinaryfile() - Determination of NTv2 file names matching reference system
  2. Function getntvdirmatch() - Determination of a matching NTv2 file in a common directory
  3. Function getntvrefbelong() - Determination of the second NTv2 Reference System
  4. Function getntvrefequiv() - Determination of an NTv2 equivalent Reference System
  5. Funktion getntvrefstatus() - Determination of the NTv2 membership of a Reference System
  6. Function setntvbinaryfile() - Test and initialize a NTv2 binary file
  7. Function setntvbinautodir() - Set directory for the automatically use of NTv2 binary files
  8. Function setntvbinautofile() - Provide a NTv2 binary file in a wait position
  9. Function setntvpolyvalid() - Set Polygonal Validity Check in NTv2 files

Ausführliche Funktionsbeschreibungen

Detailed descriptions of all geodetic functions of this function group you find here in the online manual!

KilletSoft News In order that you always are well informed about our company, we write actual news, current information and special offers here into this column.

KilletSoft Logo NTv2 files
Geosoftware for inserting area boundaries as Polygonal Validity Scopes in NTv2 files.
 Read the Worksheet...

KilletSoft Logo Geodata International
A new release ot "Geodata International" is available since July 2018. The database contains 282 contry files with Towns and Municipalities, Town Districts, Coordinates, Postal Codes etc.
 Read more...

KilletSoft Logo NTv2 Toolbox
The new program NTv2Tools provides tools for analyzing and processing of NTv2 files.  Read the Description...

KilletSoft Logo NTv2 files
Geosoftware with Tools for analyzing and processing of NTv2 files.
 Read the Worksheet...

KilletSoft Logo PolyGonal Validity Scopes
The new program NTv2Poly complements NTv2 files with Polygonal Validity Scopes that are taken from an outline shapefile.  Read the Description...

KilletSoft Logo Very big NTv2 files
Solutions for problems with large NTv2 files in GIS and Geosoftware  Read the Press Release...

KilletSoft Logo GDA2020
The new geodetic Reference System GDA2020 of Australia is supported by TRANSDAT and GeoDLL now.  Read the Press Release...
 View the list of CRS...

KilletSoft Logo BWTA2017
Baden-Wuerttemberg has completed the close-meshed NTv2 grid file for the transformation of geodata in real estate cadastres to UTM/ETRS89.
 Read the Press Release...

KilletSoft Logo GoogleMaps / OpenStreetMap
KilletSoft converts Geodata for Navigation in free Map Services.
 Read the Worksheet...

KilletSoft Logo Quality Analysis
Practice oriented Accuracy Verification of the Software TRANSDAT and GeoDLL with an extremely structured NTv2 grid file.
 Read the Worksheet...

KilletSoft Logo Innovation Award 2016
Award 2016 KilletSoft's geodetic software has won for the second year in succession the Innovation Award from the Initiative Small and Medium Enterprises.
 Certificate TRANSDAT...
 Certificate ORTWIN...
 Read the Press Release...

KilletSoft Logo GeoDLL / TRANSDAT
Proposal for using Polygonal Validity Scopes in NTv2 grid files.
 Read the Worksheet...

KilletSoft Logo Translators wanted!
The programs TRANSDAT and SEVENPAR support language files for the programs interface. Since the language dependent texts are managed in external files,  new languages can be added at any time by creating new language files. Everybody who is interested can translate a new language file into his native language for himself and all users.