| 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 refer to Ordnance Survey web
page; http://www.ordnancesurvey.co.uk/oswebsite/pai/pdfs/PAI_Companion.pdf
|
Air graphic survey
(Air ground survey)
| A technique
of using enlarged vertical aerial photographs to assist the updating of maps by graphic survey methods.
|
| Cartography | The science and art of map making.
|
| Chief
Surveyor | 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.
|
| Control point | A physically monumented
point for which coordinates of a known quality have been defined (for example, triangulation station).
|
| Definitive Map | 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, restricted byways,
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.
* BOAT = "Byway Open to All
Traffic"
** RUPP = "Road Used as Public Path", now superseded by "Restricted Byway"
|
| Definitive Statement | 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.
|
Digital Field Update
| A superseded
system of updating digital maps in the surveyor’s field office.
|
Digital
map
Geometric Fidelity | A map in a form suitable for storage, transmission and manipulation by computers.
The principle of Geometric
Fidelity is that any real-world alignment or shape must be accurately reflected in the data to the required specification.
Detail that is square on the ground must be represented as square in the data; shapes must be accurate; alignments
that are straight in real life must be represented as straight lines within the data; lines of sight that pass through points
on the ground should pass through the map positions of the corresponding points; adjacent features should be in sympathy with
each other as regards alignment, distance apart and orientation.
|
| Graphic
survey | A method of survey based upon reproducing the relationship between lines of sight, short measurements and
the construction of right angles.
|
Instrumental survey
| Any form
of survey using high precision optical or electronic instruments. |
| Land
survey | The science and mathematics of measuring the Earth and features on it, and recording the data in a methodical
way.
|
Large scale survey (map)
| A survey
(map) at one of the basic scales of 1:1250, 1:2500 or 1:10 000.
|
| OS
MasterMap® | OS
MasterMap® was designed by Ordnance Survey as an intelligent digital map and digital
representation of the real world, to be used with geographical information systems (GIS) and database systems. It is a business
tool to manage information, aid analysis and speed the decision making process. It provides intelligent data with real-world
objects represented as explicit features, each identified by a unique number.
|
| National
Grid | 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 and Ordnance Survey for supply of survey 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.
|
Optical tacheometry
| A method
of measuring distances by use of a theodolite or level.
|
Ordnance Survey
| The National Mapping Agency of Great Britain.
|
OS
Sitemap®
(Location Map) | An Ordnance
Survey product which is a printout from the Ordnance Survey digital mapping database of the latest available large scale survey.
|
Pan-Government Agreement
Photogrammetry | The Pan-Government Agreement (PGA) was managed on behalf of central government by the Intra-Governmental
Group on Geographical Information (IGGI). In general terms, membership of the agreement
was open to organisations that employed civil servants. The range of potentially eligible organisations
was broad and included crown and non-crown bodies, government departments, executive agencies and sponsored bodies.
The Pan-Government Agreement has been superseded by the Public Sector Mapping Agreement (PSMA).
A
high precision technique, used world-wide, for survey applications using photography, (usually vertical, aerial photographs).
|
| Positional
Accuracy Improvement (PAI) | The Positional Accuracy Improvement programme dealt with improving the Absolute Accuracy
of 1:2500 scale mapping 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). However,
any surveyed changes also conformed to the Geometric Fidelity and Relative Accuracy of those standards of survey. A
full explanation is available on Ordnance Survey web page http://www.ordnancesurvey.co.uk/oswebsite/pai/pdfs/PAI_Companion.pdf
|
| Precision | The ability of an instrument
or process to repeat measurements to a stated tolerance.
|
| PRISM | 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.
|
Production Group Manager
Public Sector Mapping Agreement (PSMA).
| 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 1st April 2003 as Region Managers and Assistant Region
Managers.
From
1st April 2011 the Public Sector Mapping Agreement (PSMA) replaced the Pan Government Agreement. Under PSMA public sector
organisations in England and Wales have access to most of Ordnance Survey’s mapping data under a single agreement for
the first time.
|
| Resurvey | A new
survey, not based upon earlier surveys.
|
| Revision | The updating
of an earlier survey.
|
| Scale | 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.
|
| SIM® | 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.
|
| SIP® | Superplan
Instant Printout. A copy of updated Ordnance Survey large scale mapping taken from the digital archive for security and archive
purposes.
|
| Superplan® | A copy
of a large scale Ordnance Survey map printed on demand from the latest Ordnance Survey Landline data.
|
| Theodolite | An instrument used for measuring angles in the horizontal and vertical planes.
|
| Tolerance | The maximum acceptable difference between measurements
on a map and the equivalent true measurements on the ground.
|
| Topographic
map | 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.
|
| Validation | The process of quantifying the accuracy and precision of a survey.
|
