does a compass point to true north or magnetic north
magnetic north
title: North Magnetic Pole text: exactly the direction of the North Magnetic Pole (or of any other consistent location). Instead, the compass aligns itself to the local geomagnetic field, which varies in a complex manner over the Earth's surface, as well as over time. The local angular difference between magnetic north and true north is called the magnetic declination. Most map coordinate systems are based on true north, and magnetic declination is often shown on map legends so that the direction of true north can be determined from north as indicated by a compass. In North America the line of zero declination (the "agonic line") title: Magnetic declination text: Magnetic declination Magnetic declination, or magnetic variation, is the angle on the horizontal plane between magnetic north (the direction the north end of a compass needle points, corresponding to the direction of the Earth's magnetic field lines) and true north (the direction along a meridian towards the geographic North Pole). This angle varies depending on position on the Earth's surface and changes over time. Somewhat more formally, Bowditch defines variation as “the angle between the magnetic and geographic meridians at any place, expressed in degrees and minutes east or west to indicate the direction of magnetic north from true north. title: Magnetic deviation text: Magnetic deviation Magnetic deviation is the error induced in a compass by "local" magnetic fields, which must be allowed for, along with magnetic declination, if accurate bearings are to be calculated. (More loosely, "magnetic deviation" is used by some to mean the same as "magnetic declination". This article is about the former meaning.) Compasses are used to determine the direction of true North. However, the compass reading must be corrected for two effects. The first is magnetic declination or variation—the angular difference between "magnetic North" (the local direction of the Earth's magnetic field) and true North. The second is "magnetic title: North text: compass for navigation, set a bearing or azimuth of 0° or 360°. North is specifically the direction that, in Western culture, is treated as "the" fundamental direction: Magnetic north is of interest because it is the direction indicated as north on a properly functioning (but uncorrected) magnetic compass. The difference between it and true north is called the magnetic declination (or simply the declination where the context is clear). For many purposes and physical circumstances, the error in direction that results from ignoring the distinction is tolerable; in others a mental or instrument compensation, based on assumed knowledge of the title: Compass text: local magnetic meridian, because the magnetized needle at its heart aligns itself with the horizontal component of the Earth's magnetic field. The magnetic field exerts a torque on the needle, pulling the North end or "pole" of the needle approximately toward the Earth's North magnetic pole, and pulling the other toward the Earth's South magnetic pole. The needle is mounted on a low-friction pivot point, in better compasses a jewel bearing, so it can turn easily. When the compass is held level, the needle turns until, after a few seconds to allow oscillations to die out, it settles into its