Accuracy

The relationship of the position of a feature shown on a map to its true position. Accuracy can be absolute or relative and defined mathematically. For a fuller explanation the reader is referred to Ordnance Survey Information Leaflets Accuracy of large scale mapping, Guide to the accuracy of OS control and Ordnance Survey Consultation paper 3/1997 – Positional accuracy of large-scale data and products.

A technique of using enlarged vertical aerial photographs to assist the updating of maps by graphic survey methods.

The science and art of map making.

A middle management post within Ordnance Survey responsible for a number of headquarters based staff with a specific production role in the maintenance of the national mapping archive. Up to 31 March 1999 the title also applied to field based middle managers, thereafter known as Production Group Managers, and from 2003 onwards as Region Managers and Assistant Region Managers

A physically monumented point for which coordinates of a known quality have been defined (for example, triangulation station).

A map that is a legal record of a public’s rights to walk, ride or drive on public rights of way.
NOTE: The duty of the responsible surveying authority is to show on the Definitive Map all footpaths, bridleways, BOATs and RUPPs in its area, whether urban or rural. Definitive Maps are prepared everywhere in England and Wales except in the area of the former London County Council (LCC) where their preparation is optional.
BS7666, part 4, 1996.

The Definitive Statement is a legal textual record which accompanies the Definitive Map.
NOTE: The Definitive Map and Statement provide conclusive evidence (that is, evidence that can be used in court) of the existence of public rights of way and their extent, legal conditions and limitations.
BS7666, part 4, 1996.

A system of updating Digital maps in the surveyor’s field office.

A map in a form suitable for storage, transmission and manipulation by computers.

A method of survey based upon reproducing the relationship between lines of sight, short measurements and the construction of right angles.

Any form of survey using high precision optical or electronic instruments.

The science and mathematics of measuring the Earth and features on it, and recording the data in a methodical way.

A survey (map) at one of the basic scales of 1:1250, 1:2500 or 1:10 000.

A rectangular grid used on most modern Ordnance Survey maps to enable each object on the map to be uniquely referenced in terms of distance east and distance north of a defined origin (see Ordnance Survey Maps - a descriptive manual by J. B. Harley, Ordnance Survey, Southampton 1975).

NIMSA

National Interest Mapping Services Agreement; NIMSA was an agreement between government snd Ordnance Survey for supply of survet and mapping services needed in the national interest.  Under this agreement Ordnance Survey was charged by Government with maintaining the definitive, consistent record of the natural, man-made and cultural landscape of Britain up to date, and with disseminating this information to customers in government and elsewhere.  This involved carrying out some activities that were not commercially viable.  NIMSA was terminated in December 2006 since when Ordnance Survey has been required to be self financing.

A method of measuring distances by use of a theodolite or level.

The National Mapping Agency of Great Britain.

An Ordnance Survey product which is a printout from the Ordnance Survey digital mapping database of the latest available large scale survey

The Pan-Government Agreement (PGA) is managed on behalf of central government by the Intra-Governmental Group on Geographical Information (IGGI).  In general terms, membership of the agreement is open to organisations that employ civil servants.  The range of potentially eligible organisations is broad and includes crown and non-crown bodies, government departments, executive agencies and sponsored bodies.

A high precision technique, used world-wide, for survey applications using photography, (usually vertical, aerial photographs).

The Positional Accuracy Improvement (PAI) programme dealt with improving the Absolute Accuracy from 1:2500 scale Overhaul accuracies to either 1:1250 scale Resurvey standards (for the built-up areas of defined rural towns) or 1:2500 scale Resurvey standards (the remaining rural areas).

The ability of an instrument or process to repeat measurements to a stated tolerance.

Portable Revision and Integrated Survey Module; a portable Pen Computer which enables the surveyor to update and edit Digital Maps at the time of survey.

From 1999 up to 2003 a middle management post within Ordnance Survey responsible for a number of field based staff with a specific production role in the maintenance of the national mapping archive.  Up to 31 March 1999 these managers were known as Chief Surveyors, and after 1^st April 2003 as Region Managers and Assistant Region Managers.

A new survey, not based upon earlier surveys.

The updating of an earlier survey.

The relationship between a distance measured on the map and the equivalent distance measured on the ground, for example, a scale of 1:10 000 means that a measurement of one unit on the map represents a measurement on the ground of 10 000 units.

Survey Information on Microfilm.  A copy of updated Ordnance Survey large scale mapping taken from a microfilm copy of the surveyor’s working document for security and archive purposes

Superplan Instant Printout. A copy of updated Ordnance Survey large scale mapping taken from the digital archive for security and archive purposes

A copy of a large scale Ordnance Survey map printed on demand from the latest Ordnance Survey Landline data

An instrument used for measuring angles in the horizontal and vertical planes.

The maximum acceptable difference between measurements on a map and the equivalent true measurements on the ground.

A map which depicts physical features on the ground at the time of survey, within the limitations imposed by the particular scale and specification of the map. A topographic map does not show property boundaries.

The process of quantifying the accuracy and precision of a survey.