Projection utility programs

This page contains links to utility programs which allow the user to perform a variety of common projection calculations. 

If you need a precise transformation to transform your coordinates between the GPS coordinate system (ETRS89) and National Grid (OSGB36), then you need to use our Coordinate Transformer utility.

If you want to convert the format of your coordinates (between latitude and longitude, grid or geocentric cartesian coordinates) whilst remaining on the same datum then you can download a Microsoft® Excel 2002 spreadsheet . There are also a variety of other projection functions such as local and line scale factors, convergence and t-T in the spreadsheet, as well as an approximate Helmert type transformation. ** PLEASE NOTE - the spreadsheet uses some user defined functions for essential calculations.  When opened the spreadsheet may display a security warning regarding macros.  The macros must be enabled in order for the spreadsheet to function correctly. **

If you are uncertain which of these two you require then you need to read our Guide to coordinate systems in Great Britain.  The guide can be considered essential reading for anyone trying to work with coordinates in Great Britain and an excellent source of information and gentle introduction into what can be a very confusing subject.

The guide is also the user manual for the spreadsheet above.

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