1. triangulation point: a recoverable point on the earth, whose geographic coordinates have been determined by angular methods with geodetic instruments. A triangulation point is a selected point, which has been marked with a station mark, or it is a conspicuous natural or artificial object. Also called trigonometric station or triangulation station. (IHO Dictionary, S-32, 5th Edition, 5646)
  2. observation spot: a point used by surveyors for determining precise position by astronomical means. (IHO Chart Specifications, M-4)
  3. fixed point: a point whose position has been accurately determined and plotted. (IHO Chart Specifications, M-4)
  4. bench-mark: a permanent, stable object containing a marked point of known elevation with respect to a datum used as a reference level for tidal observations or as a control point for levelling. (IHO Dictionary, S-32, 5th Edition, 462)
  5. boundary mark: a marker identifying the location of a surveyed boundary line (Digital Geographic Information Standard - DIGEST, Oct.87)
  6. horizontal control, main station: a station in a network of permanently marked control points having their geographic positions established to form third order accuracy or better. (Canadian Hydrographic Service, Survey Standing Order, 3.1-85)
  7. horizontal control, secondary station: a station in a network of control points of a localized nature utilized for shoreline plots, sounding marks, stadia work, etc., whose geographic position may be established to a slightly lower order than main control points. (Canadian Hydrographic Service, Survey Standing Order, 3.1-85)