Cartesian coordinates abscissa aim altitude aspect attitude bearing bearings bent celestial navigation compass bearing compass direction coordinates course current cylindrical coordinates dead reckoning declination direction direction line drift equator coordinates exposure false horizon fix frontage heading helmsmanship horizon inclination latitude lay lee side lie line line of direction line of march line of position longitude magnetic bearing navigation ordinate orientation pilotage piloting point polar coordinates position position line quarter radio bearing range relative bearing right ascension run sea line sensible horizon set skyline steerage steering tack tendency tenor track trend true bearing vector visible horizon way weather side