Field Navigation part 1

 

Introduction

     This weeks exercise is aimed at navigating to five predetermined points around the Priory using a navigation map that was created in exercise three and a compass. This archaic technique is very useful when navigating in areas where GPS signal is weak or nonexistent, such as forests with dense crown cover.

Study Area

      Formerly St. Bede's Monetary, the Priory was purchased by the UW-Eau Claire Foundation in 2011 and is currently being leased to the University of Wisconsin- Eau Claire for expanded educational purposes. It is located about three miles South of the City of Eau Claire, WI (Figure 1). It is currently being used as a day care center for professors with young children. It is also used as dormitories for UW- Eau Claire students. The Priory consists of 3 buildings totaling around 80,000 square feet of space on a 112 acre forested lot. The land is heavily wooded and contains a combination of flat terrain along with very steep ridges with slopes up to 63 degrees (Figure 2).

Figure 1  Locational map of the Priory. The Priory is located three miles South of Eau Claire in Eau Claire County, WI.

 

Figure 2  Original navigation map that was used in this exercise. It contains 5 foot contour intervals, an elevation model that was set to 50% transparent, and an underlying aerial image.

In many areas magnetic declination would need to be considered. However, in the study area the magnetic declination is only about negative 1.4 degrees. Areas on the East coast have magnetic declinations up to 20 degrees. This could cause a huge problem when in the field if not taken into account.

Methods 

      The methods associated with this exercise were quite simple. To start we plotted the points, in order, on the navigation map based on the UTM coordinates that where provided by the professor. We then connected the lines in order that were to be collected (Figure 3). We measured the distance on the map and converted it to real life distance using the scale bar. We then converted that into the number of paces it would take to get to each point. We then set the compass on the map, set the orienteering arrow to geographic north on the map, aligned the magnetic needle within the orienteering needle, and followed the direction of travel arrow. After arriving at the first of the points we did the same process. Set the compass on the straight line to the next point, set the orienteering arrow to geographic North, aligned the magnetic arrow inside the orienteering arrow, and followed the direction of travel arrow. An example of the process is shown in Figure 4.

 

Figure 3 Navigation map showing our plotted points and the straight line from 1 point to the next.

 

Figure 4  Cartoon showing the basic process of setting up the compass. Here, they line of the compass along the start/destination line, set the compass dial to true north on the map, align the true north arrow and the magnetic arrow, and follow the direction of travel arrow while counting paces.

 

Results

Seen below are two of the photos that were taken at the predetermined locations. They were marked by bright pink tape wrapped around birch trees (Figure 3,4) These photos were taken to provide evidence that the points were actually located. We were able to locate all five points in order with relative ease. The most difficult aspect of this exercise was scaling the valleys that were present in the Priory.

Figure 5  One of the navigation points as marked by the bright pink tape.

Figure 6  Another of the navigation points.



Conclusion

As previously stated, this lab was fairly easy. We were able to located all five points in under an hour and a half. Keeping the pace count correct was sometimes difficult because we had to navigate around dense brush and very steep slopes. Therefore, the pace count was used as more of an estimate as to where we were located instead of an actual measurement unit. There were a few cases where our pace count was off by 20 or 30 paces. This is not a problem when searching for bright pink tags located on birch trees, however this could have been a problem if navigating to something less noticeable. In addition, being in such a small geographic area made the relativity of the pace count less of a problem. If we were navigating in a national forest that spans several hundreds of miles our location would have been way off from the actual points. Another important factor is that predetermined points were actually located off the map boundary. This made it difficult to originally mark them accurately. We were also not able to have information about the slope of the area or an aerial image that could have been used to located the points easier.