Houghton's Pond Trail-O
May 16, 2010

The accompanying map shows the course with the correct flags being in the center of the circles and the incorrect flags indicated with purple X's. The approximate locations of the viewing stations are indicated with small purple circles, however they could be off by as much as 20m. The course went in a counter-clockwise direction.

Answers: C – C – D – Z – B – D – C – A – D – A

  1. C The circle on the map is at the end of the trail but still 3m from the edge of the clearing. Flags A and B are in or at the edge of the clearing, and flags D and E are at what looks like a trail but is really nothing.

  2. C The spur is indicated by two contour lines on the map, so the circle is centered on the middle of the spur. Flag D is not on the centerline of the spur. To determine which of the remaining 3 flags is the correct one, you can use distance estimation. Flag C can be seen from the small trail to the east; if you go to a point on that trail that is due east of the flag, and count paces to the main road (or to the bend in the trail to the north), the distance is correct for the center of the circle and C is the flag. Flag B is 8m north of flag C.

  3. D The reentrant is indicated by two contour lines on the map, so the circle is centered below the middle of the reentrant. Four flags are in the reentrant; pace counting along the small path (from either the road or the bend in the trail) or a compass bearing from the bend in the trail shows that the correct flag is the 2nd flag from the right. This is flag D, since there are 5 flags visible: the 4 flags in the reentrant, and the flag on the spur used for control #2 that can also be seen from the viewing station.

  4. Z All of the visible flags are to the south of the boulder field to the NW of the trail. This can easily be seen by taking compass sightings from the edge of the clearing, or by noting that the flags are not in the reentrant where the control circle is centered.

  5. B The correct flag is in line with the two boulders to the east, and 13m from the center of the west boulder. The edge of the swamp can not be used to determine the correct location because this edge depends on the season of the year and the recent moisture conditions. Pace counting along the trail determines the correct flag.

  6. D Each flag is on the south side of a boulder. However only the largest boulder is positioned on the map. The other smaller dots on the map indicate a boulder field, not the individual positions of boulders. So the correct flag is the one by the largest boulder.

  7. C Three of the flags are on the stone wall. The correct flag is due west of the east-west rock face, and can be determined by compass sightings.

  8. A The center of the circle is on a contour line. The key is to note that the rock face to the north, across the small trail, is below the contour line. So if you follow the elevation from the top of the rock face over to the spur, only one flag is that high up on the spur.

  9. D The control description says “between 2 cliffs”. “Between” refers to the mid point of the shortest imaginary line joining the edges of the 2 features. For cliffs, the edge is defined as the foot of the cliff, not the middle or top. Only 2 of the 4 flags are at the level of the feet of the 2 cliffs. Of those 2, the left one is at the edge of the SE cliff, while the right one is midway between.

  10. A This control features a parallax problem. In order to determine which flag is at the corner of the stone wall, you have to move south along the road until you can sight along the wall. It is then easy to see that the correct control is the flag second from the left. However, this is not flag B as seen from the viewing station, but rather flag A.