Introduction
In October, field navigation maps were created in preparation for this field activity, which involved using a GPS and field compass for two separate excursions in a forest. The objectives were to gain experience in navigating in the field using the two different technologies, team work, problem-solving, and field work. The Bad Elf app was utilized once again to create tracklogs of the routes the students took in the field. The class was divided into groups of three, tasked in locating five specific marked trees using a navigation map and the two previously mentioned technologies.
Study Area
The navigation took place at Priory Hall of UW - Eau Claire and it's property. The navigation maps previously created display the boundaries of the study area (Figure 1).
The navigation took place in the forests primarily north and east of the Priory building. The forest is thick with deciduous trees, samplings, and shrubs, with a patch of conifer in the eastern part of the study area. The ground is relatively level near the Priory building, but it gets increasingly variable slopes towards the edges of the study area. Deep gullies cuts into the land (Figure 2). The trees have shed their leaves, completely covering the ground, which makes traversing the steep slopes difficult.
The navigation took place in the forests primarily north and east of the Priory building. The forest is thick with deciduous trees, samplings, and shrubs, with a patch of conifer in the eastern part of the study area. The ground is relatively level near the Priory building, but it gets increasingly variable slopes towards the edges of the study area. Deep gullies cuts into the land (Figure 2). The trees have shed their leaves, completely covering the ground, which makes traversing the steep slopes difficult.
Figure 1: Field navigation map showing the study area encompassed in the rectangle.
Figure 2: An image of the terrain in the study area.
Methods
Upon arrival at the Priory, each group was given five UTM coordinates and they were to mark the points on the navigation map chosen by the professor (Figure 3). The students were to use the points on the map and the coordinates to help them find the marked trees in the field. Then, a student per group paired their smart phone to a Bad Elf GPS, as demonstrated in a previous activity, and used the Bad Elf app to create a tracklog of the group's navigation to the points (Figure 4).
Figure 3: The UTM field navigation map used to plot the coordinate points for the Navigation Activity.
Figure 4: The location of the group given by the Bad Elf app.
The groups set out on their given courses to their first point. One person was in charge of the GPS and tracklog. Another was in charge of relating the GPS location to the map. The the last individual kept track of the compass bearings and finding appropriate routes to the point of interest. In the field, however, the roles blended together and became less defined.
It took some trial and error and frequent map and GPS checks to figure out how to relate the GPS to the map in order to confidently decide on the direction to travel. These pauses were necessary because navigating required both hands and full attention in order to search for the marked tree and to prevent injury from scratching branches, tripping, and falling (which happened regardless).
The group finally arrived at the first marked, but there was some confusion as to if this was the correct marked tree. The coordinate location of the tree didn't match the given coordinate on the map, but the two coordinates were within 50 meters - which was a qualification by the professor that meant it could be the correct marked tree. The fact that it was marked by a pink ribbon was also a concern. Some in the group were under the impression that the trees were marked with spray paint, while others thought ribbon-marked trees were a possibility from past classes. Since a spray-painted tree wasn't found in the vicinity of the ribbon-marked tree, it was decided that it must be the first point. A photo was taken to document the location. (Figure 5). Finding the bearing and relating the GPS to the map, the group set out to Point 2.
Figure 5: Point 1 marked by a pink ribbon.
The group eventually found a tree marked by pink ribbon within the 50-meter radius of the given coordinate point (Figure 6).
Figure 6: Point 2 marked by a pink ribbon.
The group discovered the third marked three, but were dismayed to find it clearly marked in spray paint (Figure 7). Labeled as C-4, P-3, there was no denying this was the correct tree. This made the likelihood that the previous trees weren't the correct trees.
Figure 7: Point 3 marked with spray paint, labeling the tree as Point 3 for Course 4.
After studying the map, the group decided to navigate to Point 4 by traveling through the bottom of the gully that branched to the point. The ground was soft and muddy at the bottom of the gully, but because there were no thickets, navigating was much faster. Point 4, marked with spray paint, stood where it was expected, except at the top of the gully (Figure 8). Climbing the steep slopes was difficult due to the leaves making the ground slippery. The leaves had also almost hidden a deer ribcage, which startled the group as they unexpectedly almost stepped on (Figure 9).
Figure 8: Point 4 marked with spray paint, labeling the tree as Point 4 for Course 4.
Figure 9: A deer ribcage discovered by the group.
The group decided to return to the bottom of the gully in order to navigate to Point 5, which stood on a ridge adjacent to the gully. However, under the of time, the group misinterpreted the grid system on the navigation map in relation to the GPS and climbed the wrong side of the ridge. The smart phone was on the verge of a dead battery, so the group returned to the Priory parking lot. There, the tracklog was downloaded to the smart phone where it could be sent to other group members as a KML or GPX file (Figure 10).
Figure 10: The tracklog of the GPS navigation excursion downloaded to the smart phone.
After the tracklog was downloaded, the Bad Elf GPS was prepared for to record for another tracklog for the the second part of the field activity. This involved using the navigation map and a compass that has features like a Bearing Indicator, Orienting Arrows and Lines, Direction of Travel Arrow and Lines, and Bezel. The objective was to navigate by compass to three of the points that groups previously navigated too. To do this, take the edge of the compass to trace a straight line from the current location to the desired location (Point 1) on the navigation map from a flat surface. Next, align the Direction of Travel lines with the line that was drawn. Turn the Bezel so that the Orienting Lines are parallel to the lines of longitude on the map. Then the Bearing Indicator will point to the bearing on the compass. Since declination for Eau Claire is approximately 1 degree, subtract that from the bearing given by the compass and adjust the bezel to the bearing corrected for declination. Now hold the compass with the Direction of Travel in the opposite direction of the operator. The operator should now rotate until the red magnetic needle hovers within the red Orienting Arrow. Therefore, the operator proceeds to where the the Direction of Travel Arrow points to with the red Magnetic Needle remaining in the red Orienting Arrow. This will direct the operator to the point of interest.
The members of each group were appointed jobs to make navigation more effective. The Leap Frogger is the individual that moves to a landmark within the bearing and watches to make sure the Pace Counter, the person in charge of counting the paces to establish the distance, stay on course. The Azimuth Control makes sure that the Leap Frogger and the Pace Counter stay within the bearing. Thus, each member of the group proceed to the point of interest.
It was immediately apparent that the thicket made it almost impossible for the Leap Frogger and the Pace Counter to stay on course within the bearing, and the Azimuth Control needed to frequently direct the Leap Frogger back to a position in the bearing. The Leap Frogger ended up becoming the landmark for the other group members because landmarks weren't distinguishable in the brush. Paces stayed within 10-20, because the Leap Frogger quickly became invisible in the thicket.
The group discovered a marked three, but it was labeled as a point for a different course. Coincidentally, some 50 meters off, Point 1 for Course 4 was discovered by another group that was looking for the point found by Group 4. So the two group swapped their locations to document their point (Figure 11). It was then discovered that the Azimuth Control had the group follow magnetic north, which was nearly the same as the Direction of Travel. Incidentally, Point 1 was nearly north of the starting point. This is why the group was slightly east of the point of interest. It's also important to note that Point 1 was marked with spray paint, meaning the first Point 1 marked with the pink ribbon was not correct, and Point 2 most likely. Given the time, the group returned to the parking lot to return the equipment, end the tracklog, and download it to the smart phone.
Figure 11: The true Point 1 marked with spray paint, labeling the tree as Point 1 of Course 4 - discovered by compass navigation.
Results
According to Figure 12, Group 4 was extremely close to Points 1 and 2, almost right on top of Point 1. This is curious because the group ended up documenting the wrong trees. Point 3 and 4 were correctly documented. A wrong path was taken before Point 3 and the group had to backtrack. The tracklog shows the group passing right through Point 5, but in reality, the group was on the other side of the deep gully. If one were to take the tracklog at face value, Group 4 appears to have done very well. It should also be noted that GPS failure created distorted sections in the tracklog that were corrected in ArcMap.
Figure 12: The tracklog of the path taken by Group 4 to the five points of Course 4.
All the groups' tracklogs appear in Figure 13 (absences led there being no Group 2). All groups appear to have done well, except for Group 7 failing to navigate to two points. Perhaps that was due to time restraints.
Figure 13: The tracklogs of all the groups and their paths to their course points.
The second tracklog (Figure 14) shows the groups relatively straight path north, when in reality, the group should have been traveling in a slightly northwestern direction. The tracklog also shows the group moving west to Point 1.
Figure 14: The path taken by Group 4 to Point 1 using a compass and map.
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