Debrief of 17 Jan 1999 training
Classroom portionInstructors lectured on use of topographic maps and compasses, magnetic declination, geodetic data and UTM coordinates. The procedure for using map and compass to determine location by "resection" was described.
Classroom feedback:The instructors solicit feedback from attendees which will be placed here. Send feedback to the team mailbox and we will include it here.
Taking bearingsThe instructors pointed out a number of prominent features surrounding the training location, which was on top of a knoll at Tijeras Pueblo, UTM 373.9km,3882.2km. Team members used their compasses to take magnetic bearings to those features. Participants converted each bearing to true bearing by applying declination.
Feature recognitionParticipants were asked to find each of those features on their topographic maps (USGS Tijeras 7.5 Minute Quadrangle).
ResectionHaving identified features on the map and taken bearings to those features, participants plotted their position by finding the intersection of lines through the features which made the appropriate angle with North. Most teams obtained their position to well within one hundred meters.
Field exercise feedbackThe instructors solicit feedback from attendees which will be placed here. Send feedback to the team mailbox and we will include it here.
Navigation courseFour waypoints were placed around the Cedro Peak area. Participants drove to the Chamisoso Canyon parking lot, and were grouped into teams of two or three. There were four teams, the first three with three members and the last with two. Team 1 consisted of two prospective members of varying team experience and a potential member who has still not had an orientation, team 2 of an experienced active member, a prospective member and another potential member, team 3 of an active member, a prospective member and a potential member, and team 4 of an experienced active member and a prospective member. (Names withheld to protect the innocent, though we were tempted not to)
Teams were sent from the parking lot at approximate UTM coordinates
374.0,3880.9 to navigate the course depicted below (excerpt from
USGS Sedillo 7.5 minute quad: UTM easting coordinates have been drawn
in near the UTM grid lines, and all UTMs quoted on this page are
estimated visually from the graphic below, not from careful
measurement from the map; they are provided to help you find the
points we describe here without too much effort)
Point "A" was located a short distance northwest from a trail, point "B" west of a rise on the ridge (appx UTM 375.7km,3880.5km), point "C" in the saddle of the next ridge to the south, and point "D" on a small hill near the powerline easement. The wide path left by an old powerline cut has been drawn in in grey, and leads directly from the trail to the top of Cedro Peak.
Instructors' pathThe path taken by the instructors in setting out the course is illustrated below. We hiked to the trailhead at 375.0km,3881.0km, and walked along the trail until reaching the marked saddle. Our position was determined by resection using Cedro Peak and another prominent peak not shown in the graphic, and verified using a GPS unit. We then walked along the trail until we came to the old powerline cut and took a bearing on Cedro Peak to mark our map with the line of the cut. We determined that the powerline cut would take us directly to the ridge on which we had planned to put out point "B", so we hiked up the cut. We checked our position carefully at several points along the cut to determine when we were on the same ridge as point "B:" a quick examination of the map shows that we would encounter a long, relatively flat area that had a slight drop-off along the cut before it began to rise again. We would then proceed in a westerly direction until we found the rise after the saddle. When we reached the point marked "B" we again performed a resection to verify our position and put up the marker in a tree. We returned to the powerline cut and continued toward Cedro Peak. Point "C" was located by continuing along the powerline cut until the slope of the trail became steep following a prolonged level stretch and the terrain began to rise somewhat steeply to our left, at about 7100 feet, UTM 376.3km,3880.2km. We then followed the ridge to our right at about a constant elevation through very dense brush until the terrain opened up and we could see the saddle. Navigation to the saddle was simple, and again we verified our location with a quick resection using Cedro Peak and the same prominent peak used to locate point "A", and again verified this location with a GPS receiver. We then chose to navigate to "D" somewhat indirectly, choosing to go down the drainage to the south of point "C" and follow the unmistakable wash west to the powerline easement, then follow the powerlines almost directly to "D." Once again, the point "D" was verified through resection and GPS. We completed the loop by making a beeline towards the trail, reaching the trail slightly to the east of where the 26 is on the map. Our path is indicated below on the reduced copy of the map.
We chose this route for several reasons. First and foremost, the powerline cut made a very clear "handrail" along which we could walk with little concern for vegetation, it afforded us an excellent view of Cedro Peak throughout, and we were able to draw the straight line from our starting point northeast of point "A" directly to Cedro Peak along the cut. Once we had that line drawn, it was much easier to relate the terrain we passed to the contours on the map. It also seemed to us that the best way to get to point "C" would be to follow the cut until it was no longer an easy hike and then just follow the contour of the land directly to point "C." We chose our route to "D" to avoid most of the steep slopes, even though we had to move in the opposite direction for a short time.
Team 1's routeTeam 1 took a much more direct approach to the navigation, and in fact chose a somewhat difficult way to find "A:" They walked along the road to the sharp bend to the northwest of "A," performed a resection to verify that they were in fact on the part of the road where the map said there was a bend, figured out what magnetic bearing they would have to walk from that bend directly to point "A." They found the point easily, but we would comment that by doing this they neglected the very clear "handrail" provided by the trail. Had "A" been a less obviously marked point, they might easily have missed their destination by choosing this technique.
From point "A," team 1 decided to approach "B" almost directly. They walked straight from point "A" down to the wash along a bearing which would take them to the small feature at 6700ft elevation near UTM 375.5,3880.8, which they felt would be pretty easy to identify as it is a fairly distinctive, flat spot along the path to "B." They then proceeded directly up the side of the ridge to the top and found marker "B." Their path to "C" was similarly direct. They planned to follow contours similar to the way the instructors did, but when the got to around 7000feet they decided that the beeline path to "C" "didn't look all that difficult" and just walked a bearing to "C," even though it took them down about 100 feet and up some steep slopes again. From "C" they walked an almost straight path to "D," again because the slopes "didn't look too bad."
Remarkably, despite the somewhat strenuous path they chose, team 1 made it through the entire course in almost exactly three hours.
Team 2Team 2 found point "A" just as we did, by following the trail. They tried to follow a beeline bearing to point "B" but spent some time looking for the marker in the saddle to the east of the marked point. They did find point "B" after a while, and chose to follow contours to "C." From "C" they attempted a beeline path to "D" but mistook the lower part of the ridge holding marker "B" for the rise holding marked "D" and walked about a half a mile before deciding they'd made an error. Once they dropped down into the wash they realized where they were and found point "D", then returned to base by going north to the road.
Team 3Team 3 found point "A" by walking along the trail to a point somewhat southwest of the marked point, and then performing a quick area search of the area to the north and west of the trail. From A they located a somewhat cleared path toward "B" which they followed to the drainage south of the powerline cut at about 375.7,3880.8, then proceeded up the drainage almost directly to "B." They returned towards the path they used and continued on a course almost parallel to the powerline cut, and turned south somewhere near the coordinate 376.1, 3880.5, following the contour of the land and finding point "C" in the saddle. They proceeded down the steep drainage to the north of "C", then down the east-west drainage to the powerlines. During this descent one of the team members lost a radio, met up with team 2 and accompanied them for a time until team 2 began to explore the wrong rise. Since it was getting late the team decided to return directly to base along the powerline easement, properly choosing not to remain in the field without the ability to communicate with base. Since they followed the powerlines, they came very close to point "D," but chose not to look for it.
The radio was found the next day
Team 4Team 4 chose to navigate the course in nearly the opposite order so that they could navigate without being tempted to follow other teams. First they found "A" as the others did, but proceeded directly to D by following a bearing along the flat area between "A" and "D." From "D" they navigated to "C" via a relatively direct path, and then to "B" by following the contour of the land. They followed the powerline cut back down to the trail and returned to base.
Course feedbackThe biggest item of feedback received about the course was that the instructors had underestimated the amount of time needed to run it: we had stated it would take 3-4 hours, but one team took nearly five hours. The participants who brought this up didn't think the course was too long or difficult, just that the next time we do it we should allot more time for it.
While we had originally planned to lay out six markers, one participant commented that the four we did actually lay out was just about right.
The instructors solicit feedback from attendees which will be placed here. Send feedback to the team mailbox and we will include it here.