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Surveying Glossary

Here are a few basic surveying/mapping terms and definitions that you may come across.

Bench Mark:

A survey point on a fixed object, the altitude of which has been surveyed in relation to mean sea level. Many of these are now being replaced with GPS stations. (see below)


A type of surveying that determines the boundaries of land parcels.


The organisation and communication of geographically related information in either graphic or digital form. This usually means the drawing of maps and charts.


A line drawn on a map joining locations of equal height. Many of these at different heights indicate the shape of the landscape.


Sometimes know as DTM, this is a series of points which depict the shape of the topography of the land, or of an object being measured.


Global Positioning System using a network of satellites and receivers to identify a point in its real world location. Car Sat Nav systems and some mobile phones use this.

Laser Scanner:

A piece of equipment containing a laser which records many thousands of 3D points of a subject. Many visual fly-throughs and computer games are generated by this type of instrument.


Airborne laser scanner system which accurately measures the shape of the ground. The data may be used for flood monitoring and prediction, building detection and building heighting, tree height measurement and general DEM production.


The science of obtaining reliable measurements from photographs.

Spot height:

A point on the earth’s surface for which the height above a reference datum is known.


The determination of the absolute and relative positions of points, on or near the earth’s surface , by means of measurement in the three elements of space; distance, direction and elevation.

Total Station:

Equipment used for measuring distances and angles.

For more definitions, please take a look here: ordnancesurvey.co.uk.