This calculator may be used to calculate the magnetic declination for a specified location and date based on the International Geomagnetic Reference Field model.
If you do not know your latitude and longitude consult one of the following sites:
- For locations within Canada:
- Gazeteer Map Service (Atlas of Canada)
- For locations outside Canada:
If you know the Universal Transverse Mercator (UTM) coordinates for your location, you can convert them into geographic coordinates (latitude, longitude) by consulting the following website:
Geomagnetic reference field
The International Geomagnetic Reference Field model is used to compute values within Canada and elsewhere in the world and it is provided with a disclaimer. The relatively small differences between the model values and the true values of the magnetic field at a given location are dependent on a number of factors:
- The accuracy of the model will worsen at locations close to the magnetic poles.
- As the time from the epoch of the model increases, uncertainties in the estimate of secular variation will result in an increasingly large difference.
- Magnetic minerals in local geological formations cause magnetic anomalies that can sometimes be very large. These cannot be reproduced by reference field models.
- Large magnetic storms can temporarily cause large changes in the magnetic field, especially at high latitudes.