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Latitude – the latitude of a feature is its angular distance on a meridian,

measured northwards or southwards from the Equator.
Longitude – an angular distance measured east or west along the equator
from a reference meridian (Greenwich).
Magnetic north – the direction as indicated by a compass to the earth
magnetic pole.

Map – a representation of the Earth’s surface. A cadastral map is one
showing the land subdivided into units of ownership; a topographic map is one
showing the physical and superficial features as they appear on the ground; a

thematic map displays a particular theme, such as vegetation or population
density.
Map projection – any systematic way of representing the meridians and
parallels of the Earth upon a plane surface.

Mercator projection – the conformal cylindrical projection tangential to the
Equator, possessing the additional valuable property that all rhumb lines are
represented by straight lines. Used extensively for hydrographic and aeronautical
charts.

Meridian – an imaginary line from the North Pole to the South Pole
connecting points of equal longitude.
Relief – the deviation of an area of the Earth’s surface from a plane. It refers
to the physical shape of the surface of the Earth.

Rhumb line – a curve on the surface of a sphere that cuts all meridians at the
same angle; the path that maintains a constant true bearing.
Topography – description or representation on a map of the physical and
cultural surface features.

Transverse Mercator (TM) projection – a conformal cylindrical map
projection, originally devised by Gauss, also known as the Gauss-Kruger
projection. As its name implies, its construction is on the same principle as the
Mercator projection, the only difference being that the great circle of tangency is

now any nominated meridian. Meridians and parallels are curved lines, except for
the central meridian for a specified zone (meridian of tangency), which remains a
straight line. The amount of scale distortion may become unacceptable at
distances greater than about 1.5 degrees in longitude from the central meridian.

WGS84 – World Geodetic System 1984 – a geocentric geodetic datum
developed by the United States Department of Defense for use with GPS.

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