Field Activity 8: Navigating With a Map And Compass

Introduction

Field Activity 8 is designed to utilize maps created in Field Activity 7 to navigate through terrain at the Priory on UW- Eau Claire. The construction of maps beforehand is extremely important so that one may get an idea of what terrain they should expect when out in the field. The Priory is an extremely densely wooded area, so one should be prepared to navigate through that. Activity 7 creates topographic maps so that when one goes out in the field, they are prepared to view the terrain around them and navigate without aerial images of the study area helping them. Much like many studies, the points are pre-plotted so, having very accurate maps is important to be able to find them when a geographer goes out into the field. Having analog maps, and being able to navigate them is important because technology can always go down, and it is better to be prepared than not if one is forced to use non-technological means to complete study.

Figure 1: Study Area

Methods

Materials

• Field Notebook
• Pen/Pencil
• GPS
• Topographic maps (Field Activity 7)
• Compass

The first step to do when one gets to the Priory is to mark down the five points that they are going to go find out in the woods (Figure 2). The GPS used is turned on, and set to UTM coordinates, to coordinated with the topographic map and the next step, which is a pace count. To accomplish the pace count, one marks out a length of 100 meters, walks down and counts their paces, walks back and counts again. Once this is completed, the person studying the area averages the two counts to discover their pace count. This is important to get an idea of distance when they are out in the field using the maps an way points to discover their location. It is a good idea to write down their pace count down on the map to remember it when they are out in the field. 

Figure 2: Field Map with points and bearing written down

The next step is to record the bearings from the starting location to the first point, and then from point to point for each point after that (Figure 2. This gives the geographer a basis to navigate through the woods, before going out. After the bearings are recorded the next step is to go start finding points. At the starting point, and each consecutive point, a person hold the compass flat at chest height and sets the bearing using the red in the shed method. After that, the a spotter int he group starts walking, counting their paces until the get to their pace count which equals 100 m, and then the group continues to follow that method, going along by an interval of 100 m, eventually getting to their point of interest. This is done to navigate all the way from the start to point 5. The GPS is consulted if one feels completely lost.

Results/ Discussion

As with most studies, the results are not as easily collected as the instructions say. Due to the incredibly dense woods of the Priory, many struggle getting through the brush without losing their direction and pace count, when it is not possible to walk in a straight line. When this happens, it is important to consult the compass to check the bearing, as that is a very good indicator of where one is going. Due to this, it becomes easy to get lost (Figure 3). For Group 1, they thought they were lost a couple times due to losing their pace count, only to be right where they should have been a couple times.

As one can see, many of the track logs weave through the study area, which indicates the difficulties experienced through the activity. Group 1's track log is different due to using a different GPS unit, which collected a line .shp file to log the track. Looking at the image, one can see many of the groups crossed each others paths, although not at the same time. For Group 1, some of the weave backs can be attributed to being ~.5 of a degree off on their bearing on one navigation to a point. This caused them to walk past their 3rd point, and eventually brought them to their fourth. From there, they walked back to the third point, which is the northern most part of their track, and then navigated to their fifth point after that. This shows that preciseness is extremely important when using any instrument to navigate, as even a tiny discrepancy can cause huge errors when the errors are expanded to much larger areas. Technology also had difficulties when importing the .txt file of the points studied. The points are imported, and transferred to xy data and they show up far off of the study area.

The UTM side of the map is extremely helpful when completing this activity. All of the points are set up in UTM, and the GPS is too, so being able to look at the three of those can be extremely helpful when way off track. The degrees decimal map was far too course to use on this course, as navigation becomes difficult when attempting to navigate that big of a grid. Next time, Group 1 would add a polygon of the starting area, as that was difficult to spot on the topographic map to start off on.

Problems

• Group 1 members did not send the pictures of the points visited.
• When the point .txt file was imported, the points showed up in ArcMap far south of the track logs.

Conclusion

As one can see, the construction of precise maps is very important when navigating using any instrument. Correct bearings are also extremely important, as small discrepancies can cause huge errors when magnified to much larger areas.  An important lesson one can take away from Filed Activity 8 is to always be prepared whenever they go out in the field, as it can be an immense help to have all of the details right.