Field Activity #7 Part II: Map and Compass Navigation

Introduction

This is the second part of the navigation activity at the Priory. The previous blog post contains details about the Priory and the two navigation maps that I made, one in UTM (in meters) and one in WGS (decimal degrees). This week, the task was to use the maps we created to navigate to five points somewhere on the Priory property relying mostly on a navigation compass. The class was split into small groups for this activity. Group 5 consisted of Anneli, Jackie, Jeffrey, and Amanda (myself). Prompted to choose one group member’s map for use in the field, Anneli’s was selected. Her use of 5m contour lines instead of 2m contour lines increased the readability of the map noticeably (Fig1). This navigation activity took place late in the afternoon in early November, but it was a remarkable warm and pleasant 62°F. The weather was slightly overcast, but no precipitation.

Figure 1 Our navigation map for Group 5, hitherto known as Team Thundernado. Map designed by Anneli. Notice our destination points marked with black X's. 

Materials Provided:

•         Trimble Juno GPS
•         50m measuring tape
•         color printed 11x17” copies of the navigation map designed by one of our teammates
•        A Brunton navigation compass
•          A list of 5 waypoints to locate
•          Pink plastic marking ribbon

I also brought two clipboards and a Nikon CoolPix AW120 camera.

Compass navigation is a simple skill, but it does require some specialized knowledge. More information on how to navigate with a compass can be found here.  There is also a video tutorial at the end of this blog post. The compass we used was transparent so that you could see the map features underneath (Fig2).

Figure 2 The compass we used to measure the distance between points and to find the direction of travel. Notice the green arrow is pointing in the direction of our first destination point on the map.

Methods

Upon arrival at the Priory’s main parking lot, the class received their waypoint coordinates and tools. A lesson on how to use compasses and GPS units was given by Dr. Hupy. We used the 50m measuring tape that was laid out to assess our individual pace counts. Anneli and Jackie plotted the waypoints onto the map using the list of coordinates issued to us.

Our team designated roles to each member. I had worked with compasses before, so I volunteered as the compass holder. It was my job to find the bearings from the map and point us in the right direction. Jeff, in his conveniently visible yellow shirt, was designated as the “runner”, who would go ahead of the group, directed by the navigator, and serve as a landmark for the pacers. Jackie and Anneli were the pacers, who would calculate the distance between the points using paces and walk in the given direction in as straight a line as possible. Jackie held the GPS unit, which we were to consult as a backup source of information The GPS’s tracking function was enabled so that our exact path could be downloaded in the form of a track log later. But in the moment, we needed to rely on measurements on the map converted to meters, converted to Jackie and Anneli’s pace rate. 

Within the larger navigation area, our points on the map were clustered within a 250x250 meter range in a wooded area that included a series of steep ravines connecting a dry creek bed. In order to get from the starting area to point 1, we decided to use the compass for direction but rely on landmarks more than paces, since this was a 330m stretch through thick brush and landmarks were distinguishable on the map. Using a nearby shed as a landmark, we navigated to point one easily and then check our location on the GPS (Fig3). 

Figure 3 In the left picture, Jackie is standing about 3 meters from point one. Jackie and Anneli consulted the GPS to ensure we were in the right location.

Navigating from point 1 to point 2 led us through a meadow of tall burs and grasses (Fig4). Jeff ran ahead and encountered a coyote, which became our unofficial mascot for the remainder of the activity.  Challenges came when the pacers encountered a steep ravine that was overgrown with thick brush and could not walk a straight line through. We relied heavily on the GPS to locate point 2, and we eventually realized that there was no marker on the location. We used our pink tape and marked a tree that was our closest estimate.  

Figure 4 The field between points 1 and 2, where Jeff (seen in the background) encountered a coyote. 

 Locating point 3 was relatively simple since it was on the edge of a stand of red pine that were equally spaced and easy to pace through (Fig5).  Point 4 was also simple for this reason. The route between points 4 and 5, however, brought us back through the steep creek bed. Pacing through that was complicated more by the large amount of old refrigerator parts, jars, and other not-properly-recycled goods littering the ground. Jeff ran ahead in the given direction and was able to spot the marker of point 5.

Figure 5 Team Thundernado in action! Amanda (left) crouches to find bearings to the next point, simultaneously joking about asking Sasquatch for directions. Jackie and Anneli (center) enjoy a break in the brush and some easy pacing. Jeff (right) demonstrates the "red-in-the-shed" principle of compass use: the compass is held against his torso,  and the other points in the direction of the next destination when the red arrow in the compass aligns with the "shed" in the dial.  

Figure 6 In all, it was a good day. We encountered a coyote, learned some new skills, and found all five of our points. 

Track Logs

Because the GPS unit we carried with us was tracking our location, the efficiency of our actual route can be examined by mapping the “track log” as a line feature. I designed two maps, one with the track log information and waypoints for just our group (Group 5), and another with all 6 groups' track logs and waypoints. 

The map of just Group 5’s endeavors:

In Arcmap desktop 10.4.1, I added a basemap of aerial imagery and zoomed in on the navigation area. 

Our track log was made available by Dr. Hupy in the form of a point class shapefile. I opened it in Arcmap and used the Point to Line tool to connect the dots and clearly demonstrate the path that we took on our navigation journey.

Adding the waypoints themselves to the map was a puzzle, since no shapefiles were provided, only lists of coordinates in a text file. Taking the coordinates of the waypoints from the list, I made an excel sheet with all of the waypoints for Group 5 (aka my group, Team Thundernado). The table had

Figure 7 Group 5's waypoint coordinates.

a Point_ID field, an X field, and a Y field (Fig7). 

I then imported the table into Arcmap and used the Make XY Event Layer tool to convert the coordinate points to actual points on the map. I also used the Project tool to set the coordinate system to WGS 1984 from the coordinate system the points were originally in, which was UTM Zone 15. I only did this because multiple layers in my data frame were already in WGS 1984; otherwise UTM Zone 15 would have been preferable. Since event layers don’t automatically save to a geodatabase, I exported the data to my Priory geodatabase as Destination_Points. I then had a point feature class of the waypoints that could be labelled and used to check the efficiency of our path as reported by our track log.  

In order to add a dotted line to highlight the most ideal and efficient path between the points, I exported my Destination_Points feature class to my Priory geodatabase and then ran the Points to Line tool on the destination points. I also digitized the start location and added that.

The map of all 6 group track logs:

 Track log data for groups 1-6 was downloaded and imported into ArcMap as shapefiles in my Priory geodatabase. All data was projected to WGS 1984 for the sake of consistency. The track log information for groups 2-6 (the feature class showing their path on the map as recorded by the GPS that was with each group during the activity) was originally in a point feature class. I used the Point to Line tool to convey the track log data into lines so that the path each group took would be clearer (Fig.8).

Figure 8 Results of the Point to Line tool, shown here on Group 5's data. 

 The use of this tool unearthed an interesting error with the tracklog data from Group 4. The line that was mapped to connect all of the location points continued and led to a mysterious location that was far away from the location of the navigation activity. This fun little mystery was solved by zooming in to the points at the end of the mysterious line (Fig9). This problem was easily remedied by deleting the erroneous points in Arcmap and then rerunning the Point to Line tool on the data from Group 4.

Figure 9 Apparently the tracking mechanism in GPS unit 4 was activated again after the unit had returned with the class to the main UWEC campus. You can see on the inset map that the device began transmitting again in the campus mall area. Perhaps another geography class was doing a project on campus with the GPS units and the track log never got turned off.

 Adding the waypoints to the map was expedited this time by Dr. Hupy emailing a text file of all of the waypoints X and Y coordinates.  In order to create a shapefile of the destination way points to compare the tracklogs too, I imported the text file as a table to my geodatabase and then used the Make an XY Event Layer tool. This plotted the points onto the map. I exported the event layer into my geodatabase so that. The coordinates were in UTM Zone 15 though, so I used the Project tool to project them into WGS 1984.

Results

This navigation activity went smoothly overall, but we did rely on the GPS to help direct us to points 1 and 2 more than we used the pacing and compass method. Also, we neglected to send the GPS unit with Jeff when he walked across the ravine to point 5, so on our track log it looks as though we skipped point 5.  It was difficult to use the pace-count method since the terrain and dense vegetation made traveling in a straight line impossible at times. You can see that our path, shown in purple on Figure 10, was not the most efficient. Also, there was a lot of ambiguity around the location of point 2 since the marker was missing. We wandered around in the woods a bit, and that is evident. 

Figure 10 The map of our waypoint coordinate locations. The purple line represents our path.  Ideally, we would have travelled in a perfectly straight line from point to point, but that clearly was not what occurred. 

Surprisingly, our group still fared better in efficiency than most of the other groups in class. It is clear that, as a class, we all relied heavily on the GPS coordinates to navigate. If we had only compass and pacing to navigate by, then we would have all traveled in straighter lines. 

Figure 11 All 6 group track logs are mapped here. It is unclear why many points appear to have been un-accessed.

In conclusion, this activity was a stretching experience. It opened my eyes to the challenges that most of human history, who did not have pre-processed data and GPS technology to rely on, faced in navigating the world. I respect the challenges that they overcame in mapping and orienteering in order to bring us to where we are today.

For more information on navigating with a map and compass, check out this video!