static synchronized void release() {
            if (refCount > 0) {
                refCount--;
                Log.d("ResourceBitmapCacheMonitor.release");
                if (refCount == 0) {
                    Log.d("ResourceBitmapCacheMonitor.clearResourceBitmaps");
                    AndroidResourceBitmap.clearResourceBitmaps();
                }
            }
        }
Repaint position overlay but only with a max frequency and if position or heading changes sufficiently.
main/src/main/java/cgeo/geocaching/maps/mapsforge/v6/NewMap.java