visée rétrograde

OBS: Dans un cheminement, concerne toutes les visées faites dans le sens opposé au sens dans lequel on chemine.
OBS: visée rétrograde; visée arrière : termes en usage à Ressources naturelles Canada - Secteur des sciences de la Terre.

CONT: A backsight is a reading taken on a position of known coordinate(s). Since a survey progresses from a point of known position to points of unknown position, a backsight is a reading looking ""backward"" along the line of progress. The first reading of almost any survey job should be a backsight onto a fixed point of reference, usually a benchmark of some sort.
OBS: In traversing, a backsight is a sight on a previously established traverse or triangulation station, which is not the closing sight on the traverse; in leveling, a backsight is a reading on a rod that is held on a point whose elevation has been previously determined and is not the closing sight of a level line.
OBS: Backsight is opposed to foresight.