Geographic North, or True North, is the direction pointing toward the Geographic North Pole—the location where the longitudinal lines converge in the Northern Hemisphere. The direction in which a compass needle points is called Magnetic North. Magnetic North differs from True North because the magnetic field of the Earth is complicated and is not aligned with the geographic poles. The angular difference between Magnetic North and True North varies by location and date and is called magnetic declination. By correcting for this declination, compasses and other instruments that rely on magnetic field to indicate direction are able to report True North.

The Go Direct Weather (GDX-WTHR) uses the Earth’s magnetic field to determine wind direction. To display True North, the magnetic declination of your location must be entered in the sensor’s attributes. Once the declination is set, you will not need to change it unless you change locations. A quick internet search will provide calculators to help you determine the current magnetic declination at your location.

Follow the steps below to set the declination for your Go Direct Weather.

1. Launch Graphical Analysis or Graphical Analysis Pro app.
2. Connect the Go Direct Weather Sensor to your Chromebook, computer, or mobile device.
3. In the list of Connected Devices, click or tap the Device Information icon, ⓘ, for your sensor. The Device Information dialog will open.
4. Click or tap Advanced to expand the Advanced options.
5. Enter the declination value to the closest degree for your geographic location.
6. Click or tap Save to save your settings.
7. Close the Device Information dialog box.

The declination will be saved on the Go Direct Weather device and will be used to determine True North for each subsequent use.