Mapping Terminology
- Bearing
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The horizontal angle at a given point, measured clockwise from magnetic north or true north to a second point.
- Classified roads
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Roads for which surface type, width and use are identified.
- Bearing
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The horizontal angle at a given point, measured clockwise from magnetic north or true north to a second point.
- Classified roads
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Roads for which surface type, width and use are identified.
- Contour lines
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Lines on the map connecting points of equal elevation above mean sea level; using contour lines, relief features can be profiled into a three-dimensional perspective.
- Elevation
- Vertical distance from a datum (usually mean sea level) to a point or object on the earth's surface.
- Horizontal datum
- The positional reference or basis for the geographic location of features on a map.
- Magnetic declination
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The angle between magnetic north and true north, expressed in degrees and minutes, east or west from true north.
- Magnetic north
- Direction to which a compass needle points.
- Mean sea level
- The average height of the surface of the sea for all stages of tide, used as a reference surface from which elevations are measured.
- Projection
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Geometric representation of the curved surface of the earth on a flat sheet of paper.
- Relief
- The physical configuration of the earth's surface, depicted on a topographic map by contour lines and spot heights.
- Spot elevation
- A point on a map where height above mean sea level is noted, usually by a dot and elevation value; it is shown wherever practical (road intersections, summits, lakes, large flat areas and depressions).
- Surveying
- The operation of taking observations or measurements to determine geographic location.
- Topography
- Surface features both natural and cultural, collectively depicted on topographic maps.
- True north
- Direction of the northern rotational axis of the earth - the North Pole.
- Unclassified roads
- Roads for which the surface is unidentified.
- Universal Transverse Mercator (UTM) grid
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A square grid system based on the Transverse Mercator projection, depicted on maps. It can be used to accurately locate the position of features on the map by distance or direction.
- Vertical datum
- The reference or basis for elevations (usually mean sea level).
Find out more about the National Topographic System, UTM Projection, and Symbols used on NTS maps.