I'm also in SA and I just entered it as a negative, the setup accepted it, shouldn't be a problem
Hi Gareth, I got -17.32 for Pretoria - entered it like that and looked at the Flight Data page while rotating and turning the quad - looks within 10 deg to my untrained eye. Now I guess its up to flight testing...
-24.5 here in Cape Town :-(
Works fine in my UAV.
You need put -18.8 into APM Planner
Becuase Your Position Declination is a WEST or Negative it's a ( - )
But, If Declination is a EAST or Positive it's a (+)
Now , I live in Bangkok. My Declination -0.38 or 0.38 WEST. And I compare between real compass and my Magnetometer . You should compare real compass (don't compass in Iphone or you moblie phone) Real Compass !!!!