Final Land Navigation

Introduction:

This week’s activity brought an end to our land navigation exercises. We were tasked with using everything we learned thus far in a game of paintball at the Priory land. By applying a culmination of skills learned in previous weeks, we were required to locate and navigate to the points throughout the course in the most efficient manner possible.  We used the week to create new maps, including the point locations and off limit boundaries, as well as develop a strategy for our team’s success.  Each of the six teams were able to determine their own course of action, making encounters very likely.  This exercise provided a fun activity in which we could hone our skills and show what we learned throughout the land navigation section of our geospatial field methods class.

Study Area:

Once again the study area for this week’s activity was the 112 sq acre Priory land purchased by the University of Wisconsin Eau Claire in October of 2011. Figure 1 below shows the location of the Priory from the UWEC campus. Having already navigated this course, we were familiar with the terrain making it much easier to establish a sense of direction.

 

Methods:

During week 1 of our land navigation project, we began preparations for compass/map navigation.  This traditional method provides an effective means of travel without the reliance on technologies such as the global positioning system (GPS).  The only elements required for this technique are distance and direction. The use of a compass and a map provide you with the needed information to determine direction, while a 100 meter pace count offers you the element of distance.

We began by establishing our pace count using the TruPulse range finder, used in our distance azimuth survey, to measure 100 meters.  After measuring 100 meters, determining your pace count is as simple as counting every other step from start to finish.  My recorded pace count ended up being 65 steps; however, since this was a straight line path, on concrete, I decided to add 10 paces to account for being in the woods and traveling in a less linear path. Using the scale included on my maps, I can measure the map distance between each point and associate it with my pace count to determine my ground distance.

The second portion of land navigation week one, involved using ArcMap to create the maps used during the exercise.  The only requirement for these maps was that they use a UTM grid reference system.  Since the points are being provided to us in UTM, we have to use the same grid system to determine their location.  I decided on using two maps, one with very detailed contour lines to easily distinguish changes in relief (figure 2), and the other showing a clear aerial photograph to distinguish changes in vegetation (figure 3).  As you can see in figure 2, the major terrain features are made visible using 2 foot contour intervals. Figure 3 shows the contrast between the different vegetation quite clearly.  For both maps, 50 square feet grid intervals were used to keep them cluster free while plotting the points.

During the second week of the land navigation activity, we put our maps and pace counts to use using a traditional map and compass technique. Traditional land navigation not only retracts from our reliance upon technology that often fails, it also provides an accurate and efficient means of travel.

The first part of compass/map navigation is plotting the coordinates of the course’s points.  These points were given to us in six digit UTM coordinates, making them accurate to within 10 meters of the point’s actual coordinates. Using the grid references on our map, made this process as simple as aligning the first three digits with the x-axis and the last three digits with the y-axis. Figure 4 shows our point locations marked on our map, point 1B being the starting point.

After plotting the coordinates, we determined the direction of travel by finding the azimuths. An azimuth is simply the straight line direction between two points with units in degrees or mils. The technique I used involved placing a military protractor on each point and aligning its crosshairs parallel to the grid lines. A straight edge can then be used to record the direction in degrees found on the outside edge of the protractor (Figure 5).

The last preliminary step before starting the course is to use the map’s scale to determine the distances between each point. This distance in meters can then be converted into your pace count so that your location on the map is known.

After all of the points were plotted, the direction of travel determined, and distances measured, we moved to our first course marker.  We began at the starting location and pointed our compass to our first azimuth towards point 2B. Once each point was found, we simply rotated the bezel on our compass to align it with the next azimuth. Using this simple, traditional technique, was quite efficient in finding all six of our points. The most difficult part of the process was walking in snow at times being two feet deep (Figure 6).  

Land navigation part three involved using a global positioning system to find a different set of points on the Priory course. This technique provided some advantages and disadvantages for finding our points.  The advantages being that it allows us to track our movement throughout the course using the track log feature, and it makes having a map less necessary since it provides your locations coordinates.  However, using a GPS also has disadvantages such as reliance on batteries, it being subject to a harsh environment, and strength of signal in dense vegetation.

For our GPS land navigation exercise, we used a Garmin etrex GPS unit. Although somewhat outdated, this unit is relatively inexpensive and useful for simple tasks such as land navigation.  By using at least three satellites, a GPS triangulates your location on a three dimensional plane in X, Y, and Z fields. This provides good locational data to be incorporated within a GIS.  After being given our point coordinates, we activated the GPS track log and moved towards the first point. Using the X and Y coordinates displayed on the GPS, we walked towards our point coordinates. This technique was very slow, as we often found ourselves walking out of our way to determine which direction we needed to go. 

Once the course’s points were found, we were able to upload our track log data to see our route. Figure 7 shows my groups track log as we navigated our course.  Right off the bat you can see our direction got mixed up in the south west area near the parking lot.

After each group uploaded their track logs, I imported the data into ArcMap. In figure 8 you can see that all 18 of the points were reached. By incorporating the time data stored by the GPS, you can see which groups were more efficient in their travel (Figure 9).

FIGURE 9 GROUPS ANIMATION

Results:

Having learned the necessary skills for both traditional and GPS land navigation, our final test was to travel to as many points as possible with the added element of paintball.  Using our experience in the previous weeks, we recreated our maps showing off limits zones and the necessary information ensuring our success. 

Once again, we used our GPS’s track log feature to record our routes; however, already being familiarized with the course, we relied much more on terrain association than the actual GPS coordinates. This provided a very efficient way of reaching the points, while staying alert for the five other groups.  In figure 10, you can see our route, along with the other groups. Our routes meeting were often accompanied by an intense firefight and a hasty retreat by one team or the other.

 

To accompany this data, I created a time animation showing each groups travel throughout the course.  Figure 11 clearly shows where groups converge on one another and a firefight occurs.

FIGURE 11 CLASS TRACKLOG TIME ANIMATION

Conclusion:

Using the methods learned throughout the land navigation portion of our class, I feel quite confident in my abilities to find feature locations using either, a compass and a map, or a global positioning system.  These skills can be used for various field activities conducted by geographers, such as collecting feature data on a study area.