On Monday, March 4th, we conducted our field navigation exercise at The Priory in Eau Claire, WI as mentioned in last week's post. The weather was overcast as we set out to the field around 3:00 PM with a slight drizzle on and off. Upon arrival, we found our respective group members and gathered inside of the building for a quick briefing on the flag locations where we were to navigate to as well as the equipment we would be allowed to use, a compass and our map. The property was large enough to accomodate 3 different courses, each containing 5 flags so that no two teams would be going the same way and thus making each time navigate alone. The courses were overlapped in areas though on purpose to add an extra challenge to make sure that if a flag was spotted from afar, it was not certain that the flag belonged to the course being navigated but could belong to a different course. This was done to ensure that we were following our compasses because a compass never lies, we were told over and over again.
Methodology
Once we were all gathered in the building, we were handed our printed off maps that we created the week before. In addition, we were given the locations of the flags for the course we were to navigate to in the form of UTM coordinates as shown in Fig. 1.
 |
| Fig. 1 |
This figure indicates the course number with the respective flag locations as well as the starting point for each course as well. My group was assigned to Course #1. Once we had this information, we started to plot out all the points on the map as well as noting the azimuth for each one based on the previous point. In Fig. 2, everyone is busy plotting their points on their own maps.
 |
| Fig 2. |
We used the UTM grid on our maps to find the location of each flag and also the starting point. This took some time as we had to double check our map readings and actually ended up plotting 2 points wrong originally so it is definitely crucial to double check or have someone else on your team take a look to get a second set of eyes to ensure accuracy. This could have been very costly and detrimental to our navigation sesssion if we had not caught these mistakes. Figures 3, 4, and 5 depict our team members plotting the points on our maps.
 |
| Fig. 3 |
 |
| Fig. 4 |
 |
| Fig. 5 |
After we finally got all the points in their right locations, we were taught how a compass works and the appropriate way to utilize it. This website does a good job describing how to use a compass along with good graphical instructions as well: http://www.learn-orienteering.org/old/. Each team member was issued a compass so that everyone got practice in understanding and using one. Obviously, it is extremely important to know how a compass works but it is also necessary to be able to get an azimuth from one point to another, using a compass and map. An azimuth is a directional reading based on a circle where 0° or 365° is north and 180° is south, 90° is east, and 270° is west. This sort of preparation is paramount before going out in the field and trying to figure it out there by trial and error. An azimuth was collected from the starting point to the first flag location and then from the first flag location the second location etc...Once out in the field we need this azimuth to determine in which direction to walk. We could estimate the distance to each point by counting the number of grid cells between each point since each grid cell is 20m x 20m. An estimate of distance is very helpful when navigating so one doesn't wander too far. Figures 6, 7, and 8 depict the process of plotting points on a map and then calculating an azimuth based off of a straight line between points. Also, in Fig. 7 and 8, the elevation range is shown which clued us in to the range of elevation we would experience in locating the flags.
 |
| Fig. 6 |
 |
| Fig. 7 |
 |
| Fig. 8 |
Once we had all of the prep work done for the activity, which took around an hour, we headed outside to the starting point for our course. From there it was just us with a map and compass and the wilderness which is shown in Fig. 9.
 |
| Fig. 9 |
The snow was still pretty deep throughout the woods and it became readily apparant that I should have worn boots instead of shoes. Anyways, this is basically what we had to navigate through, along with challenging elevation changes. Once at the starting point, we assigned one person to man the map and stay at the starting point, another person to walk a distance in the azimuth direction to a landmark (usually a tree), and then the third person to count paces from the point to where the second person was standing. We thought this would be the most effective way to stay on the right track because it is very easy to get off the correct path when there are trees in your way. Also, we applied the pace count we took the week before to get an estimate how many meters we had walked so that we had a general idea of how close we should be to the flag. Once again, this was not super accurate because we could not walk in a straight line as we had done in the control experiment but was still very helpful we found out. Navigation to the first point went fairly smoothly even though we had to descend a pretty steep incline to reach it. Figure 10 shows a bit of our navigation to the first point. Here I am counting paces between where my partner Beatriz is standing, pointing out the azimuth and where my other partner Kent is, a landmark along the azimuth.
 |
| Fig. 10 |
 |
| Fig. 11 depicting more pace counting between Beatriz and Kent |
 |
| Fig. 12 - Getting deeper into the thicket, suppressing quick navigation. |
We were not able to move very quickly through the forest due to the abundance of trees and the deep snow. However, we managed to stay relatively close to the azimuth and only ended up 11 paces to the west of where the flag was. Needless to say, we were pretty pumped and group morale was at an all time high.
 |
| Fig. 13 - The flag from where we first spotted it. |
 |
| Fig. 14 - Kent (left) and I celebrating our find! Great success! |
 |
| Fig. 15 - False Flag (tree marker) |
Morale was soon to take a hit while navigating to the second flag however. To get to the second flag, we had to descend further down into the valley, and a little further than we had to travel from starting point to flag #1. We applied the same strategy as we had done for the first point as it worked out very well for us. At this point, it should be mentioned that my feet were completely soaked and cold, but I continued on. We walked the distance that we felt we needed to go, but saw no flag anywhere so we walked further until we got to a deep ravine. Still, nothing. Beatriz and myself decided to stay at the point where we felt the azimuth and distance were correct and sent Kent out to explore the perimeter. After a time, Kent came back stating that he did not see anything. We then split up and walked all around the area near the ravine since that is where it looked like it should be on our contour map. We ended up wandering around for a good half hour before we decided that maybe we should go back to flag #1 and start over in case we miscalculated the azimuth. At this point, Martin the field supervisor, came by and told us we should look at the bottom of the ravine. We went to the same spot that we originally thought it would be and looked down to the bottom of a very steep ravine, and sure enough, the flag was pretty much at the bottom of the ravine. Here we learned a valuable lesson: always trust your compass. All we failed to do was look all the way down.
 |
| Fig. 19 - Point 3 (flag #2) shown atop elevation contours. |
Discussion
We all learned a great deal about navigation with a compass and map from the field outing. We started off strong with our navigation exercise, but failed to complete the course after just finding one flag which was very frustrating. One of the issues that was brought up between our group was that we had not really observed the elevation changes too well on our maps which caught us off-gaurd once in the field. Our maps should have shown more detail with the elevation so that it would have been a bit more obvious that flag #2 was far down a ravine. In Fig. 19, the contour lines are 2m intervals, but we should have gone finer detail with the contours. We were following the correct line, but just failed to realize that the flag was all the way down the ravine, not near the edge where it looks like it is on our maps. I blame myself for not using finer contour lines as well as not breaking up the DEM elevations into more classes which led to over generalization of the elevations. Another thing, as mentioned above, is to never second guess your compass. We doubted our compass because we did not see the flag at first, which led us to wander around aimlessly in the woods with the slim hopes of getting lucky and blindly running across the flag. Next time I need to be more prepared for the physical elements of the field by wearing boots and not shoes. Being unprepared for such elements can greatly hinder effective navigation and could also prove to be fatal if alone in the cold. Our method of navigation was very effective though, with each person assigned a different task to keep everyone on track. It is a bit burdensome trying to manage a compass on top of a paper map in the field, but it can be extremely effective though if that is one's only option. Given another shot at the course, we are very confident that we could find all of the flags. I was pretty excited to be able to navigate with a compass though, since I had never done this before. It is a very valuable skill to learn and actually quite simple once one is able to apply it to a field setting. This week, we will be out in the same area doing navigation with a GPS, using lat./long. coordinates instead of UTM
.
No comments:
Post a Comment