Is it True north? Grid North, AMG North, Magnetic North, Google North, Nautical North, Arbitrary North or some other North….???

It comes down to what you need North for and the purpose and in the design and construction industry – architects and engineers, surveyors, data managers, GIS personnel, etc, we use the different north points for their end needs.

The 3 main North options are True, Grid & Magnetic, but as you can see, there are other North Point options and I am sure there are more than what are shown here, but we think we have the key ones.

In Summary:

True North

Each day the Earth rotates about its axis. The two ends of the axes are the True North and True South poles. True North on a map is the direction along the Earth’s surface which converges on the North Pole.

Grid North

Grid North is the direction of a plane grid system, usually the grids associated with the projection of a map.

Australian Map Grid (AMG) North

The projected coordinate system based on the superseded Australian Geodetic Datum, was based initially on the Australian National Spheroid (ANS) which was an ellipsoid designed to be the best estimate of the earth’s shape around the Australian continent rather than the world.

Magnetic North

A compass needle points to the magnetic north pole. The magnetic north pole changes slightly with time and with location of the Earth’s Surface?

Google Maps North

Google Maps use a variant of the Mercator projection for its map images. The Mercator map was designed as an aid to navigators since straight lines on the Mercator projection are loxodromes or rhumb lines – representing lines of constant compass bearing – perfect for ‘true’ direction.

True North on Google Maps is not shown, but for a normal Mercator projection, grid north and true north will coincide and it will follow any vertical line (or meridian) to the top of the map. (google)

Nautical North

Pretty well aligns with True North

Arbitrary North

Arbitrary North can be in any direction at all and is not tied or linked by mathematical means to any of the north options.

Other Questions?

What is a Grid Convergence

The horizontal angle at a place between true north and grid north. It is proportional to the longitude difference between the place and the central meridian.

What is the difference between grid north and true north?

Grid north (GN) is a navigational term referring to the direction northwards along the grid lines of a map projection. It is contrasted with true north (the direction of the North Pole) and magnetic north (the direction in which a compass needle points).

The difference between grid north and true north is very small and for most navigation purposes can almost always be ignored…

What is the Horizontal difference between True North and Magnetic North.

Magnetic North aligns with the earth’s magnetic field and varies, while True north is a fixed point on the globe. The horizontal angular difference between True North and Magnetic North is called Magnetic Variation or Declination.

Sources: World Atlas, GeographyRealm, Bushwalking Manual