@Override
    public void onDetachedFromWindow() {
        periodicUpdate.clear();

        super.onDetachedFromWindow();

        if (compassUnderlay != null) {
            compassUnderlay.recycle();
        }

        if (compassRose != null) {
            compassRose.recycle();
        }

        if (compassArrow != null) {
            compassArrow.recycle();
        }

        if (compassOverlay != null) {
            compassOverlay.recycle();
        }
    }
North direction measured from device, or 0.0
main/src/main/java/cgeo/geocaching/ui/CompassView.java