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Table of Contents
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.
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 .
The compass view
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
Compass style
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.
Magnetic declination
A magnetic compass points the magnetic north (the top direction of the magnetic field) which is different from the true north (the top direction of the map). The application then tries to compute the magnetic declination
, which is the angle difference between the magnetic north and the map north, at your current location. 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. When turning on the compass, be sure to points the map over your approximate current location to get a correct declination, in case your GPS location is not known.
If you need to get the magnetic north direction instead of the true map north, or if you believe that your device already applies the declination offset, you can turn this computation off:
- In the compass view, click on the
“Settings”
icon to open the settings dialog; - Un-check
“Compute declination to get true north”
; - Click on
“OK”
.
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:
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 . As explained above, the application needs to know your approximate current location to compute a valid magnetic declination. Most of the time you just need to be sure that the map points your current location to fix your problem.
If you still believe the computed declination is incorrect or already applied by your device, you can turn off this computation as explained in the settings sections.
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.