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Using the scale bar on a map you can determine the distance between two

points on the map.

DIRECTIONS
Maps usually include a north point diagram in the map margin information.
This shows the direction of Grid North and Magnetic North at the centre of the
map.

Fig. 1.4 North point diagram describes the angular difference between
Grid, True, and Magnetic North

• True North (TN) is the direction to the Earth’s geographic North Pole.
• Grid North (GN) is the direction of the blue vertical grid lines (eastings)
on a map.The angular difference between GN and TN is known as grid

convergence.
• Magnetic North (MN) is the direction from any point on the surface of the
Earth towards the Earth’s North Magnetic Pole. The angular difference between
TN and MN is known as Magnetic Declination. As GN is used in preference to

TN for map reading purposes, it is more useful to know the difference between
GN and MN. This is known as the Grid/Magnetic angle. This varies across New
Zealand and because the position of the North Magnetic Pole moves slightly from
year to year, the Grid/Magnetic angle and Magnetic Declination will vary by a

small amount each year. In using a map for accurate navigation, magnetic
variation can be important, particularly if the map is several years old.

THE MANUFACTURING PROCESS
The production of an accurate topographic map is a long and complex
process that may take as much as five years from start to finish. It takes a skilled
team of surveyors, engravers, fact checkers, printers, and others to produce a good

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