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Monday, March 11, 2013

Assignment 6: Navigation with Map and Compass

Exercise conducted on: March 4th, 2013.

Introduction

This week we had to meet at the Priory, a 112 acre area recently purchased by the University. The maps we made last week were printed out and provided to us upon arrival. The intent of this week's assignment is to learn how to use a map and compass to navigate. Though it was not snowing or raining this time, we still had knee-deep snow to walk through for much of the trip.

Methods

Upon arriving at the Priory, we were instructed to go inside and gather our maps. We were then given a sheet of paper with UTM coordinates on them. The coordinates corresponded to the course we were going to be on. The professor had designed three navigation courses, each with six points. My group was assigned to the first course, and so those were the points we plotted on our map (Figures 1-3). Once each of us plotted our points we were given a briefing on how to use a compass and determine bearing.

Figure 1: Me, plotting our course markers on a map.  We were given a sheet of paper
with a list of each course and the respective UTM coordinates.  
Figure 2: Joel comparing his points on the map with mine, to verify that we each have our
points place correctly.  Two points were placed incorrectly, so it was good that we
compared our maps, otherwise we would have had to fix it in the field.
Figure 3: Beatriz finding the bearing to each point on the map.

When it comes to using a compass for navigation, it is important to know azimuth as well.  The azimuth, or bearing, is an angular measurement based on a circle, and is measured in degrees.  On a compass, North is 0 degrees (or 360), East is 90, South is 180, and West is 270.  Magnetic declination would be taken into consideration, however, Eau Claire, Wisconsin is incredibly close to zero declination.  The compass would then be placed on the map, with the travel arrow parallel with the intended path.  Then, the compass housing is turned parallel with North on the map.

With all of the points mapped and the bearings determined, we headed outside to begin our adventure. We were lead to the first point to ensure that we started at the correct location, and then were left alone. We decided the best way to stay on course would be to split the responsibilities three ways. Beatriz determined the bearing, I walked ahead while she told me if I need to adjust in direction, and after a while I would stop, and then they would follow, with Joel counting the pace. This process went quite well, though it was difficult to follow a straight path due to the trees (Figure 4). In short time we found our first point (Figure 5).

Figure 4: Joel and Beatriz making their way towards me.  Ask can be seen,  it is difficult to travel in a straight
line when there are trees and branches everywhere, along with snow ranging from ankle to knee deep.

Figure 5: Joel and myself (left) at the first point.  The markers are hanging from trees and
can be seen from a fair distance away.  Our bearing took us directly to it.

The second point did not go over so well. We continued with the same method we used to find the first point, this time eventually coming to a valley, with a fairly steep slope. We double checked our map, and it showed the point as being more towards the top of the ridge around the valley. We looked down into the valley and saw nothing, so we thought we may have moved off bearing for a portion of the time. I walked to the East a ways to try and find the point. Multiple times I got my hopes up when I saw flags on trees, but unfortunately they were trees that were marked for other reasons (Figure 6). When I returned to the group we took another look at the map, and felt fairly confident that the flag was all the way down in the valley. Each of us split off and branched in different directions to find it, but to no avail. After about 30 minutes of wandering we all met back up and decided it would be best to go back to our previous point and try again. Just as we were about to head back, Martin, our field supervisor, came to check on us, and was confused as to how we hadn't found the point yet. He took us no more than 10m to the East of where we ended at the top of the valley and pointed down (Figure 7). This is when we learned the lesson to always trust your compass. Though the point appeared to be on the ridge of the valley, all we had to do was look more closely to the valley itself.

Figure 6: Tree with a flag tied to it.  There were quite a few of these out there, and several times
they got us excited thinking it was the marker.
Figure 7: The flag that hid from us.  Due to the snow it is difficult to see the slope of the ravine,
but it is pretty steep.  There were trees that assisted in obscuring it, and had we been coming
from the other side it may have been easier to spot.  However, had we only trusted our
compass we would have found it much sooner.

Unfortunately it was getting quite dark and we were running out of time for the exercise, so Martin brought us with him to show us where the next point would be and to gather the other group on the same course as us (only starting at last point). Once we found the other group we headed back to the building and were done with the exercise. We were very disappointed with having found only one flag, as most other groups finished their courses.


Discussion and Conclusion

Having only found one flag, it was a very frustrating experience. We spent at least 30 minutes wandering around looking for a flag that was right in front of us had we only looked deeper into the valley. However, there were some very important lessons learned from this experience. The first is to always trust your compass. We thought we had followed the bearing properly, but because we didn't immediately see the flag like we did the first time we assumed we must have went slightly off bearing with all of the trees in the way. Had one of us simply decided to slide down the ravine to check it out, we would have found it.

Our second lesson was to ensure we have finer contour lines for future exercises at the Priory. Our map had a two meter interval, while we did have a two foot interval at our disposal. Had we used the two foot interval instead, it is likely that the point would clearly have been in the ravine rather than what appeared to be the ridge.

On the other hand, our navigation method was quite effect. Each person was doing something and it was done in an expedient manner. We look forward to doing another course so we can use this experience excel in the future.  

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