WHAT IS THE ORDNANCE SURVEY MAPPING

Upendra Kumar

Ordinance survey is the national mapping agency of Great Britain. The history of the foundation date of the ordnance survey in June 1791. The start of survey work in 1783. One is the most chapter is added in ordnance survey mapping, surveying with the help of theodolite in 1791.

The basis of ordnance surveying mapping was triangulation. Triangulation was the universal name of providing Skelton for control of survey operation. The use of a topographical survey in the ordnance survey map from 1819 and the scale of the map was 1:10560.

For purpose of land and taxes, the scale was used 1:2500 or 1:1250 and a map was drawn for this purpose on a national grid system. The national grid large-scale mapping started in 1944. The scale used for rural area 1:2500 and urban area 1:1250 for map preparation. The digital map available from 1995 on a scale of 1:25000 and 1:10000.

OLD OS MAP

BASIS OF ORDINANCE SURVEY

The original ordnance survey map was made of a triangulation survey. during the second survey in 1934 required the precise location of triangulation pillars. The location of triangulation pillars is determined by triangulation survey and build the triangulation pillars on a hilltop and it's made of concrete or stone. The modern OS survey based on GPS and AERIAL PHOTOGRAPHIC SURVEY.

The GPS station is known as OS net. OS survey used ordnance survey national grid system with longitude and latitude for location purposes. Ordnance survey also used geographical datum point with geodetic reference. Four or six digits are used for a grid reference.

In the preparation of the master copy of the OS map following layers should be used.