In {TAIL ~ this context}, {HEAD ~ the coordinate system} 100, 101, 102 can be a geographic position, for example, including elevation 102 
In
In { TAIL ~ this context } , { HEAD ~ the coordinate system } 100 , 101 , 102 can be a geographic position , for example , including elevation 102
REL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH