When you visit a classroom in the United States and see a map of the contiguous states on the wall, it's usually in NAD83 Albers Equal Area with the central meridian right at 96 West.

What is the most common projection when viewing a map of the UK?

2 Answers 2


British National Grid which has an EPSG code of 27700

There is some good info on our website - http://www.ordnancesurvey.co.uk/resources/maps-and-geographic-resources/the-national-grid.html


To expand on tjmgis's answer, the Ordnance Survey uses an ellipsoidal transverse Mercator projection with central meridian at 2 degrees West.

If you use the popular Proj4 projection library you can use these parameters to specify the projection:

+proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 +x_0=400000 +y_0=-100000 +ellps=airy +datum=OSGB36 +units=m +no_defs 

The British National Grid is not itself a projection but a way of referencing positions in the projected coordinate system and labelling 100km squares within it.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.