Cibola Search and Rescue

Land Navigation Evaluation

Instructions to evaluators

  1. Equipment and Supplies
    • Six waypoint markers (e.g. 8.5x11 cards with letters, numbers, etc.) for every course to be laid out.
    • Measuring wheel (Rolatape).
    • Topographic map of area .
    • UTM interpolator.
    • Optional: plastic overlays for map&thin-point markers, otherwise one copy of map for each candidate. Do not use enlarged copies of map, but true-size Xerox acceptable. It is preferable to tell evaluatees to procure their own copies of the actual USGS or USFS map of the area before the date of the evaluation.
    • GPS unit.
  2. Situation
    • Candidates will use a topographic map and their compasses to perform resection to find their location.
    • Candidates will walk a compass course that you will set for them, estimating distances between waypoints.
    • Candidates will use a GPS to retrieve present position information and plot the position on their maps. This exercise should be completed in a different location than the resection point.
    • Candidates will retrieve the coordinates for a point on a map selected by the evaluator. This point may be the resection point.
  3. Evaluator Duties
    • Ensure that all equipment is available
    • Lay out course according to standard:
      • 600-700 meters (1968-2296 feet,656-765 yards) in length
      • No more than 200 meters (656 feet) between any two points
      • 6 waypoints
      • moderate terrain, no major obstructions to interfere with navigation
    • Measure the bearing from the final point back to the starting location as an aid for evaluatees to find their way back.
    • Ensure that candidate teams can complete the evaluation without interfering with each other or leading each other to waypoints.
    • Mark off a distance of 100 yards (300 feet) so that candidates can use this measured distance to aid their distance estimates. Encourage but do not require them to walk this distance at a normal speed and count their paces.
  4. Evaluator instructions
    • Set out 6 waypoints, no more than 656 feet apart, for a total course of no less than 1968 feet and no more than 2296 feet.
    • As you set out your waypoint markers, make careful measurements of the magnetic bearings from one point to the next and the distance between them. Do not estimate distances, measure them with the rolatape. Important:Do not calculate bearings from GPS measurements! Use your compass!
    • Find a location at which the resection work will be done. Obtain UTM coordinates of this point BOTH by use of GPS and by resection with as many features as possible. This will be considered the "true" location of the resection point, so be precise. Important: Be sure your GPS is using the same geodetic datum as the map on which you're plotting your points! Using the wrong datum can give as much as 200 meters error over and above the error from selective availability and atmospheric conditions!
    • Find a location at which the GPS work will be done. Obtain the coordinates for this position using a GPS. Important: Again, be sure your GPS is using the same geodetic datum as the map on which you're plotting your points! Using the wrong datum can give as much as 200 meters error over and above the error from selective availability and atmospheric conditions!
    • Clearly mark a point on the topographic map that will be used for reading UTM coordinates.
    For each candidate:
    • Enter your name, the date and names of team members being evaluated on checklist
    • Place a P next to each skill which was demonstrated successfully, place an "F" next to any skill which was not demonstrated properly in your judgment.
    • If all skills demonstrated successfully mark checklist with "P", otherwise mark with "F."
    • Return completed checklist to training officer for archiving.
    • One evaluator should evaluate each candidate individually.
    • Candidates should receive a briefing along the lines of the following script:
          Here is a topographic map of this area.  Use your compass and knowledge of
          map reading to find where we are on this map.  You must locate our
          position within 200 meters ( 656 feet) using resection techniques. 
    • When candidate has finished, check that the candidate has drawn resection lines on the map or map overlay, and that these form a triangle which has at its center a point within 200 meters of the true location. To determine this, use a UTM interpolator card --- if the candidate's point is within two squares of the UTM grid of the "true" location, the candidate passes.
    • Once again give the candidates a briefing similar to the one below:
           Using your GPS, retrieve our present position and plot it on your map.
           The plotting of the point must be done to an accuracy of 100 meters (328
           feet).  After completing this you must retrieve the UTM coordinates of
           this point (the evaluator shows the marked point to candidates and allows
           them to copy the marking onto their own maps) on your map.  These UTM
           coordinates must be accurate to 100 meters (328 feet).
    • When the candidate has finished, check that the point poltted on their map is within 100 meters of the true location, again using a UTM interpolator to determine accuracy. Check the candidate's coordinates for the marked point on the map. The coordinates must be accurate to within 100 meters.
    • Give the candidates a briefing similar to the script below:
       Here is a list of waypoints you must navigate using your compass.  [At this
       time you should either provide the evaluatees with copies of the checklist
       with bearings already filled out, or read out the bearings for them to fill
       into their own copies.] It consists of a list of bearings which will take you
       from one point to the next.  All the bearings are magnetic bearings.  As you
       walk from waypoint to waypoint, estimate the distance between points and write
       them down on your checklist.  No two points are farther apart than 200
       meters/656 feet/219 yards.  The total length of the course is between 600 and
       700 meters (1968-2296 feet,656-765 yards).  If you cannot see the starting
       point from the final point, you can find it by following a bearing of XXXX.
       Your task is to navigate between the points and estimate the distances to
       within 25% accuracy --- that is, if the distance between the two points 
       is 100 yards, you need to have estimated the distance to be 75-125
       yards.  It is by getting the distances right that we know you walked the
       course properly, so do your estimate carefully.  
    • When the candidate returns from the course, compare the estimated distances to the true distances. The candidate passes if all estimates are within 25% of the true distances.