1. What is Magnetic to Grid Angle?

The angle between magnetic north and grid north is important for navigation and surveying. Magnetic north changes over time due to Earth's magnetic field variations, while grid north is fixed by the map projection.

2. How Does the Calculator Work?

The calculator uses the World Magnetic Model (WMM):

Where:

• Latitude — Geographic coordinate (-90° to 90°)
• Longitude — Geographic coordinate (-180° to 180°)
• Altitude — Height above sea level (meters)
• Date — Year of calculation (1900-2100)

Explanation: The WMM accounts for spatial and temporal variations in Earth's magnetic field to calculate magnetic declination and grid convergence.

3. Importance of Magnetic Declination

Details: Accurate magnetic-to-grid conversion is crucial for navigation, surveying, and map reading, especially in areas with significant magnetic declination.

4. Using the Calculator

Tips: Enter coordinates in decimal degrees, altitude in meters, and the year of interest. The calculator provides the angle between magnetic north and grid north.

5. Frequently Asked Questions (FAQ)

Q1: How often does magnetic north change?
A: The WMM is updated every 5 years to account for secular variation in Earth's magnetic field.

Q2: Why does altitude affect the calculation?
A: Earth's magnetic field strength decreases with altitude, though the effect is relatively small for surface navigation.

Q3: How accurate is this calculation?
A: The WMM is typically accurate to within 30 minutes of arc for declination, but local magnetic anomalies may cause greater errors.

Q4: When is this angle most important?
A: Critical for precise navigation in aviation, marine, and wilderness settings, especially at high latitudes.

Q5: How does this differ from true north?
A: True north is geographic north, grid north is map projection north, and magnetic north is where compasses point.