Exercise 11: Map and Compass Navigation

Introduction

The step up for this blog can be found in this earlier post. This exercise took us to the Priory, a university owned property with dense woods and steep ravines. The class was split into teams of 3 and sent out to navigate through one of three different courses on the property using only a map and compass. In areas of dense forest GPS signals can become weak and inaccurate, and this exercise taught us a valuable lesson that traditional navigation techniques are simple to learn, extremely accurate and very cost effective. 

Methods

Once our group assembled at the Priory, the first step was to receive the coordinates for the course points and plot them on the printed maps we created. Emily's map was used since it was the simplest design and was easy on the eyes. She also used the 5m contours which were a lot less cluttered than the 2 foot contours I had used. These points were represented by blaze orange flags hung onto trees, containing a hole puncher to prove our visit. With the five course points plotted directly on the map, we could then draw lines between each point using a straightedge in the correct order for measuring azimuth. We placed the center of the compass dial on the starting point, aligned the compass meridians with map north, and recorded the azimuth we would need to head towards to travel to each point. 

Figure 1. A compass and straightedge are necessary to accurately plot the route on a map. 

To properly navigate this course with the resources given to us, it was essential that each team member executed their role flawlessly. I was given the "runner" position which meant I would head off in the direction of travel until I was barely visible. The other team members would shout at me and tell me to move right or left in order to stay exactly on the line of travel. The next team member was the "counter", and would count the number of paces it took to travel from the starting point to me. The last team member who held the compass would then travel to us once the counting was completed and we would repeat the process until we reached the flag. Sometimes we would travel the correct distance and wouldn't arrive at a flag, so a marker like a backpack was left on the end point and we would spread out to find the flag. If we found out that we had traveled the route wrong, we would return to the backpack and adjust the route accordingly. 

Results

The navigation exercise was a success and at the end of the day, we made it to each point and safely back to the starting location. The third point that we traveled to was accidentally plotted in the wrong location by me, and resulted in us being about 200 meters off course. Luckily we included the aerial imagery on the map, and we were able to find a landmark to use as a temporary starting point while we navigated to the third point using a new azimuth measurement. Since the grid was quite large on the map, it was difficult to plot the points exactly where they should have been, but once we got to the plotted area the flag was bright enough to be seen from about 100 meters away. 

Discussion

Some small changes I think could have been made to our methods involve the map construction. The font of the UTM coordinates were very light and hard to see against the light blue backdrop of the map. Also, additional ticks in the grid would have been nice considering how accurate our points had to be in order to complete the exercise.