> Notes on the Modified British System of coordinates used on the European Theatre of Operations during the WWII
> The "Coordinates Translator"   (version française)

The nature of the "Modified British System", built on the basis of perfectly-defined map projections, allows the development of data-processing software intended to (re)localize points or targets whose coordinates were established in this system.

The "coordinates translator" which you can discover here allows the conversion from "British Modified System" coordinates, for example LZ1/vX962494, towards more "conventional" geographical coordinates (Latitude/Longitude) quite easy to use in digital atlases, as for the Mapquest web site.


Its imprecision, evaluated on the basis of a series of "gauged" points, varies from 5 to 30 arc-seconds, depending on the map projection used (this corresponds to and imprecision varying from 150 to 1000 meters on the field). The mathematic formulas used for the conversions are the "Lambert conic near conformal => Latitude / Longitude" and "Cassini-Soldner => Latitude / Longitude" described in the guide produced by the EPSG.

This translator works on the basis of complete "Modified British System" coordinates (please have a look to the system overview and to the grids for more details).

1/ Select the grid or the geographical area concerned.


2/ Enter the "Modified British System" coordinates to be decoded.


Please note that the coordinates to be decoded must imperatively be "complete" here, i.e. include the exact reference of the square used for the determination of the position (this reference includes systematically two letters, for example: vX) as well as the numerical data corresponding to the localization of the point inside this square (four or six digits according to the precision of the localization).

Two examples of coordinates likely to be entered are given below :


In case of doubts concerning the exact reference of the square, please have a look to the map projections used and the corresponding grids.

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