Online Help > Compass

Orientation & Compass


The compass feature uses the magnetic sensor of your device (if available) to give you orientation information.

To turn on the compass, you can either:

  • Long-press the “Compass” menu button ;
  • Click on the sub-menu toggle .

The “Compass” menu button color lets you know the current state:

  • When the icon is white, the “Compass” is turned off. Long-press the button to turn it on;
  • When the icon is green, the “Compass” is turned on. Long-press the button to turn it off.

compass-submenu.jpg


The compass menu


Click on the “Compass menu button to display the compass menu, composed of the following items:

  • The “Compass button opens the compass details window;
  • The “Compass toggle lets you turn on or off the compass feature easily;
  • The “Display compass check-box controls either or not to display a compass on the map;
  • The “Rotate the map check-box controls either or not to rotate the map based on the compass north to match the real direction you are looking at;
  • The “Current heading check-box controls either or not to display an information box on the map with your current heading.

You can un-check both “Display compass” and “Rotate the map” check-boxes to display a small current heading arrow .

compass-on-map-items.jpg


The compass view

compass-view.jpg
The “compass view” gives you the following information:

  • The true (geographic) north direction, pointed by the red arrow .
  • The precise heading arrow , when this one is between -20° and +20°, including mils graduation;
  • A pitch and roll level , helping you to keep the device flat;
  • The magnetic declination at your current location , which is the difference between the magnetic north and the geographic (map) north. The application uses either the last known location of your device if any, or the screen center location. This value is computed each time you activate the compass;
  • The direction to the target, if a location is set as target.


The compass settings


By default, the compass has a moving rose and graduations (the “Topochaix” style). You can change it to a moving needle and still graduations :

  • Click on the “Settings icon to open the settings dialog;
  • Click on the style list and select “Standard”;
  • Click on “OK to validate.

compass-settings-style.jpg


Problems with the compass

Compass won't turn on


If you can't turn the compass on, it means that your device doesn't have a magnetic sensor built in, which is required to get the direction of the north. Recent versions confirm it by displaying this message when trying to turn on the compass:

compass-error-sensor.jpg

Note that you can still use the map rotation using the GPS (if available), from the GPS Location menu.


Compass gives incorrect direction


When using the application compass (just like with mechanical compass), be sure to handle your device in the horizontal position, the screen looking up.


Compass need to be calibrated


When you get wrong directions from the compass, you usually just need to calibrate the magnetic sensor. This is fast and easy:

  • Turn on the compass;
  • Turn your device in the air in all directions;
  • Done!


Wrong magnetic declination


If calibrating the compass doesn't help, or if you see a strange constant offset in the direction, check the magnetic declination . This value corresponds to the difference of angle at your precise location between the magnetic north, given by the magnetic sensor, and the map north, corresponding to the top direction of the map. It's usually just a few degrees, but may be more if you're close from a pole.

To compute this value, the application needs to know your physical location. It will first try to use the GPS location or the network based location if available, otherwise it will use the location displayed at the center of the map. Most of the time you just need to be sure that the map points your current location to get a correct declination and fix your problem.

However, if you need to get the magnetic north or if you believe that your device already applies the declination offset, you can just turn this computation off:

  • In the compass view, click on the “Settings icon to open the settings dialog;
  • Click on “More;
  • Un-check “Compute declination to get true north;
  • Click on “OK to validate.

compass-settings-declination.jpg


Inverted poles


On some devices, when changing the screen orientation of 180° (jumping to the opposite screen orientation, ie landscape right to landscape left without the intermediate portrait orientation), the compass direction is inverted. Be sure to always select the portrait orientation, even temporarily.

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