It was an experiment that I never really finished as trying to draw an S using turtle commands [dating myself there] proved to be far too annoying.
To remove it, open the navigatemap_800_430.ui file in notepad and put a semi colon ; in front of this line
<VSPRITE xxx vec="$compass3d.vpr" x=100 y=130 z=-400000 rotatemodel="map.rotation_angle" visiblemodel="ui.vshowcmp&ui.vMapModeBool&!ui.vOnO verview">
Нужно закоментировать эту строку для отключения