Magnetic declination (variation) calculator based on the IGRF magnetic field model. Estimates magnetic delination world-wide from 1900 - present.

Larger-scale local maps may indicate current local declination, often with the aid of a schematic diagram. Unless the area depicted is very small, declination may vary measurably over the …

In cartography, a declination diagram is used to provide a graphic representation of the variations between true north, grid north, and magnetic north on a map.

This page allows you to look up current values for Magnetic Declination and Grid Varience for any location. Then you can see what changes as you select various combination of north …

The collar of USGS topographic maps shows the magnetic declination at the center of the map the year that the map was made. That's important information for anyone who is using the …

Oct 15, 2025 · The degrees of declination for an area are usually located on the bottom margin of the map near the north arrow, or they can be located using a declination chart.

To find the declination in your area, look in the margins of your topo map. There, you should find an illustration showing three lines: Notice that each tipped with a different symbol: GN - …

Declination is the angular difference between any two norths. If you have a map and a compass, the one of most interest to you will be between magnetic and grid north. The declination …

To obtain the true declination it is necessary to add or subtract the convergence angle to the Grid Declination. The diagram illustrates four possible combinations.

The magnetic declination calculator tells you the difference between true north and magnetic north at your location. We use magnetic declination for many applications, including navigation, …