Photograph of Ordnance Survey Minor Control Point outside Mazza Ice Cream Store, Long Row, Belper

This image is from a collection of albums created by the Ordnance Survey to identify revision points, which were used as starting points when revising the published Ordnance Survey maps of Britain. The points created a framework which was used to determine position, scale and orientation on the map.

The minor control points were marked on the Ordnance Survey 1:1,250 and 1:2,500 scale maps-initially using a lollipop symbol and later using the 'rp' symbol. However, changing survey methods rendered them largely obsolete and they were replaced in 1980 by 'permanent traverse stations'.