Navigation with Map and Compass

Introduction:

In this activity, we navigated between a series of points using a map and a compass. In order to do so, we were divided into groups of three, in order to fill three different roles: Pace Counter, Azimuth Control, and Leap Frogger. The Pace Counter walks between points, counting their paces to establish distance. The Azimuth Control stands at a point, ensuring the pace counter is staying in line with the azimuth, and telling the Pace Counter which landmarks to walk towards. The Leap Frogger moves to a given landmark to allow the pace counter to move ahead, allowing the Pace Counter to better see where they are headed and the Azimuth Control to move to the Leap Frogger's previous position.

Study Area:

The Priory is a facility owned by the University of Wisconsin - Eau Claire. It is an old Benedictine Convent, surrounded by 100+ acres of forest. Conditions were overcast, and it started to get dark under the canopy about halfway through the navigation exercise.

Figure : We conducted the survey on an overcast fall day.
Temperatures were in the mid 50's which was perfect for the exercise.

Methods:

Each group was given a list of point coordinates in UTM, and told to plot the point locations on their reference map.

Figure : Marking the lines between the plotted points.

Once we had plotted our points, we drew lines between the points and determined the bearing of the lines. In order to do this we oriented our maps with magnetic north, then rotated the compass bezel so the north arrow was still in the "shed" and the heading arrow matched our line. The bearing was the point on the bezel that lined up with the heading arrow.

Figure : Marking the bearing of the lines using the compass.

Figure  : Marked Point Locations on Map.

When marking our points we realized that the first point was directly on one of the trails, so we decided to walk along the trail in order to get to our first point. After we got to the point, we realized we had never recorded our distances, so we marked the end points of the bearing lines on the edge of a piece of paper, and measured the distance with an app on David's phone. After getting the linear distance, we converted the distances to paces, using my pace count of 64 paces / 100 meters. After writing down the pace counts for all of the bearing lines, we started navigating with myself as the Pace Counter, David as Azimuth Control, and Aly as Leapfrogger. Unfortunately, we didn't understand what the leapfrogger was suppposed to do, so Aly essentially just leaped to my position after I had paced it out, and made sure that it matched David's Azimuth.

Figure : Myself counting paces between point one and our first leapfrog point.

The area between the first and second points was densely vegetated, so we were only able to travel short distances between leaps. We ended up being fairly certain we were on the right bearing, but the full pace count left me around 10 meters short of our objective. This was likely due to the substantial obstacles I had to navigate over, including but not limited to: downed trees, remnants of an old garage, steep ravine slopes, and a 10 meter wide patch of stinging nettles. As there was actually no marker at location two, our accuracy estimate is truly only an estimate.

Figure : The woman in blue is standing where we estimated the second point to be.
I was standing where I had reached the full extent of the pace count,
an estimated 10 meters short of the objective.

The area between points two and three was primarily a jack pine forest with little to no underbrush, which made navigating a breeze. I was slightly more comfortable with my pace count, and our resulting location was still short of our objective point.

Figure : The man on the left side of the image is standing next to point three,
while I am standing where I had reached the full extent of the pace count.

This time, however, we realized that our azimuth was the major cause of error.

Figure : The Line-Of-Sight graph shows visibility from point two.
After reaching the top of the ravine, we calculated our bearing incorrectly, and we ended up at an incorrect location. 

After reaching point three, we had David and Aly switch roles.

Figure : Aly determining a landmark according to the azimuth from point three.

As we were again navigating the jack pine forest, the pace count gave us a very accurate sense of distance. We navigated the bearing in three leaps, each of which was unfortunately moving on the wrong azimuth.

Figure : If we had followed the field calculations correctly, we would have ended at the pink dot near point 4.
The tracklog points show that our azimuth very clearly deviated from that calculated heading.

Our navigation between points four and five was perfectly accurate to the point marked on the map. Points four and five were close enough together that no leaping was necessary in order to navigate between them. This certainly aided the accuracy of navigation.

Figure : The Line-Of-Sight tool shows point five was within sight from point four.

Discussion:

Our reference maps should've also had intermediate reference lines at 25 meter increments in addition to the 50 meter increments we used. Smaller increments would've allowed easier plotting of the points.

We experienced error from a number of different sources. Our navigation between points one to two, and points three to four was negatively impacted by poor azimuth readings. Our field calculated azimuths were fairly accurate, but our navigation wasn't leading to the conclusion of incorrect azimuth readings.

Sources:
https://web.viu.ca/corrin/FRST121/Help/UTM%20Coordinates.pdf