OSTN02 in NTv2 format

In its original form OSTN02 consists of a plane 700 km by 1250 km grid of 1 km resolution with an eastings shift and northing shift at each grid node.

The plane grid form of OSTN02 is not easily compatible with some GIS systems.  Some of these systems utilise a transformation data format known as NTv2.  NTv2 format is a gridded format but the grid is realised on a latitude/longitude graticule and the shifts are expressed as differences in latitude and longitude.

The Defence Geographic Centre (DGC) have converted the plane grid version of OSTN02 to an NTv2 version and have kindly agreed to allow it to be distributed here.  The difference in transformed coordinates between the original OSTN02 format and the NTv2 format is insignificant (0.001m on average, 0.01m maximum). 

The 10km off shore buffer is retained in the NTv2 version of OSTN02 so users must be aware that no transformation will take place beyond this limit.  Unlike in a dedicated implementation of the original OSTN02 grid, a GIS system using the NTv2 version of OSTN02 is unlikely to warn the user that coordinates are outside the 10km boundary and will therefore not be transformed.

 

Copyright and Liability

Copyright notice:
Copyright and any database right or other intellectual property right in the OSTN02 data available in NTv2 format, however it is made available, belongs to Ordnance Survey and Defence Geographics Centre (and is therefore Crown copyright). Ordnance Survey and Defence Geographics Centre permit users to copy or incorporate copyrighted material from NTv2 format OSTN02 onto their own PCs or into their software. However, this is dependant on the appropriate copyright notice being displayed in the software. The appropriate notice is '© UK MOD Crown Copyright, 2002. All rights reserved.' The appropriate agency logos (Ordnance Survey and Defence Geographics Centre) must also appear next to the copyright notice.

Liability notice:
OSTN02^TM in NTv2 format is provided free of charge by Ordnance Survey ® and Defence Geographics Centre on an as is and as and when available basis to users. A user of OSTN02 does so at their own risk. It is without representation, warranty or condition that OSTN02 is error free, free from viruses or other harmful components or as to the accuracy, content, completeness, legality, reliability, quality or suitability of it other than those implied by statute. Ordnance Survey shall not be liable to a user or any third party for any losses, costs, claims or indirect, special, incidental, punitive, or consequential damages arising out of access, downloading or use of OSTN02. Defence Geographics Centre furnished data is provided 'as is' and excludes all liabilities in relation to the data to the maximum extent permitted by law. Defence Geographics Centre is not liable for any errors or omissions in the data and shall not be liable for any loss, injury or damage of any kind caused by its use.

 

The OSTN02_NTv2 data file 

Download a Zip file of OSTN02 NTv2 data (4.7Mb) 

The zip file contains a text version (.txt) and a binary version (.gsb) of the OSTN02_NTv2 data file.  There is also a text file of the NTv2 header information.  Ordnance Survey and Defence Geographics Centre cannot provide guidance on how to install OSTN02_NTv2 into GIS systems.  Please contact your GIS system vendor for help with this.

Once installed it is recommended to test the transformation.  Correct transformation results can be verified using the online version of OSTN02 here.