BNGPlus

High-precision transformation between geographic ETRS89 (WGS84) and British National Grid OSGB36 coordinates
—  For use with MapInfo^®  —
Version 1.0.2

BNGPlus is a tool for the high-precision transformation between ETRS89-based geodetic (long/lat) coordinates and the British National Grid OSGB36 coordinate system. It can only be used in conjunction with the MapInfo® desktop mapping / GIS software. The transformation can be applied in both directions and produces results with a precision that is much higher (0.1 m RMS) than the standard transformation method implemented within MapInfo Professional.

BNGPlus can be applied to regular MapInfo map tables containing vector graphics, which will be transformed into new MapInfo map tables. Temporary (query) tables or "seamless maps" require a prior conversion into base tables, whereas transformations of raster images (scanned maps, aerial photos etc.) are not supported. With the special "batch processing mode" dozens or hundreds of map layers / tables can be processed in a single run of the program without any in-between user interaction.

The British National Grid, together with the geodetic reference system OSGB36 is a "traditional" national coordinate system based on a historically evolved network of triangulation stations and survey work and is not homogeneous throughout its coverage area, e.g. local/regional variations of the inherent scaling factor and other parameters can be found. The newer ETRS89 ("European Terrestrial Reference System 1989") is a modern geodetic reference system used throughout Europe, which has been newly developed with high-precision technology and recent geodetic knowledge and was defined as a very close implementation of the ITRF ("International Terrestrial Reference Frame") for Europe in the year 1989.

A widely used method to transform coordinate values from one geodetic reference system into another is to apply a combination of certain transformation algorithms in conjunction with a set of a few constant parameters which define a coherent mathematical model of the relationship between these reference systems. This is also the approach used within MapInfo Professional for most coordinate transformations.

Unfortunately, the OSGB36 reference system in relation to the ETRS89 (or the WGS84) can not be defined very precisely by a mathematical model with the same single set of a few transformation parameters for the entire area of Great Britain. The positional errors with this approach exceed 5 metres in large parts of Britain and in some regions reach levels of 10 metres and more.

Therefore, the much more precise OSTN02™ transformation method used by BNGPlus is based on a grid of 1 km wide cells with specific local transformation parameters defined for the corner points of each grid cell. This set of transformation parameters is available from the British Ordnance Survey (© Crown copyright 2002); thus, the results from BNGPlus are identical to those of the official OSTN02 transformation.

Ordnance Survey, the OS Symbol and OSGB36 are registered trademarks and OSTN02 is a trademark of Ordnance Survey, the national mapping agency of Great Britain.

Optionally, the transformation between ETRS89 and BNG OSGB36 can be combined with / supplemented by a transformation between ETRS89 (which is static in the European geodetic context) and the world-wide WGS84 / ITRF reference system. The relationship between these reference systems is dynamic – due to tectonic movement. However, the effect of this continental plate movement since 1989 is still smaller than half a metre (in Britain, 2007), so that this option is only relevant for map data with a very high precision level, based on the WGS84 (ITRF) geodetic reference system.

The documentation for this software tool is provided in the form of a Windows HTML help file (CHM file). An additional printed manual is not part of this product.

System Requirements

The BNGPlus software can only be used in conjunction with MapInfo Version 4.0 or higher. The required operating system is MS-Windows® 95/NT4 or a higher version.

Price

19% V.A.T. may need to be added for customers from a EU member country not having a EU V.A.T. reg. number.

Ordering Procedures

Orders are accepted preferably in written or printed form (e.g. via fax: +49 5232 6918956). They should specify the following details:

1. Number of BNGPlus licenses to be purchased
2. Name of company / organization; for larger firms or institutions please do also name branch, department etc., for which the software is to be licensed.
3. Name of person in charge
4. Postal / fax / e-mail address and billing address if applicable
5. Your intended mode of payment:
   - Direct (electronic / wire) bank transfer
   - Sending a cheque or "international money order"
6. Only if applicable: Your European Union V.A.T. registration number
7. Any specific requirements you might have pertaining to purchase procedures

Dispatch

The dispatch of the software will preferably be done via e-mail (ZIP file). You may request postal delivery of the program (additional shipping and handling charge of 5.50 EUR).
The invoice will be sent by fax; other options are postal delivery or transmission in an e-mail-attached PDF file.