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The Ordnance Survey (OS) is the national mapping agency for Great Britain. [ 2 ] The agency's name indicates its original military purpose (see ordnance and surveying), which was to map Scotland in the wake of the Jacobite rising of 1745.
Triangulation station. A trigonometrical station in Sunset Peak, Hong Kong. A triangulation station, also known as a trigonometrical point, and sometimes informally as a trig, is a fixed surveying station, used in geodetic surveying and other surveying projects in its vicinity. The nomenclature varies regionally: they are generally known as ...
A geologic map or geological map is a special-purpose map made to show various geological features. Rock units or geologic strata are shown by color or symbols. Bedding planes and structural features such as faults , folds , are shown with strike and dip or trend and plunge symbols which give three-dimensional orientations features.
View from Newlyn harbour showing the lighthouse and Newlyn Tidal Observatory to its right, both painted red and white. An ordnance datum (OD) is a vertical datum used by an ordnance survey as the basis for deriving altitudes on maps. A spot height may be expressed as above ordnance datum (AOD). Usually mean sea level (MSL) at a particular place ...
Survey markers, also called survey marks, survey monuments, or geodetic marks, are objects placed to mark key survey points on the Earth's surface. They are used in geodetic and land surveying. A benchmark is a type of survey marker that indicates elevation (vertical position). Horizontal position markers used for triangulation are also known ...
The various features shown on the map are represented by conventional signs or symbols. For example, colors can be used to indicate a classification of roads. These signs are usually explained in the margin of the map, or on a separately published characteristic sheet. [17] Topographic maps are also commonly called contour maps or topo maps.
A typical map with grid lines. The Ordnance Survey National Grid (United Kingdom) and other national grid systems use similar approaches. In Ordnance Survey maps, each Easting and Northing grid line is given a two-digit code, based on the British national grid reference system with an origin point just off the southwest coast of the United ...
An orienteering map is a map specially prepared for use in orienteering events. It is a large-scale topographic map with extra markings to help the participant navigate through the course. These maps are much more detailed than general-purpose topographic maps, and incorporate a standard symbology designed to be useful to anyone, regardless of ...