For the final week of class, students went back to the Priory and completed the entire navigation course with the aid of a Trimble Juno 3B GPS unit. Any data or imagery loaded onto the GPS unit could be used. It was up to the individual groups to decide what to include and what would just be clutter. Each group will start at a different flag and complete the course in whichever manner they deem the best, taking a point with the GPS unit at every flag. Being the last class of the semester, paintball was incorporated into the activity for fun. There would be five teams of three students each competing to complete the course first. If someone was hit, their team would need to wait about 1 minute before moving on.
Methods
The process of creating a geodatabase and collecting data with ArcPad is explained in pervious blog posts Field Activity #7 and Lab 5 (from my GIS I blog).
Figure 1: Screenshot of what was exported to the GPS unit. The no shooting zone polygons indicate areas were children or other Nature Academy related personal may be present. The flag positions were kept small and the navigation path was kept skinny so they would be a appropriate size on the smaller Juno 3B screen. The 5 meter contour lines and study area was kept for reference. NavigationGroup3 is the point feature class that will be used during the activity to mark the location of the flags.
Group 3 began at flag number 10 and followed the purple line seen in Figure 1 until the final flag, number 1. The GPS unit was used as a interactive map for this navigation exercise. As the location of the GPS on the screen moved, we were able to have a better idea if we were close to the next flag or not. When a flag was reached, the GPS was held under it and a NavigationGroup3 point was taken in ArcPad. The process of watching the GPS unit and taking points at flags continued until point 6 was found. At that point it was almost after 6 and the activity ended.
Discussion
Figure 2: This is a map made for reference. It illustrates the starting and ending point and the general path taken to complete the course.
The navigation path taken was largely based on x,y location and less consideration was put into elevation. The difficulty due to elevation was visually approximated and ended up making the course pretty physically exhausting. The longest portion of the course was the beginning. The class was given paintball equipment near flag 1 and students were not allowed to be seen with paintball guns and masks in any of the no shooting zones. As a result, to get to our starting position at flag 10, we had to traverse multiple wooded thorny slopes taking us at least 15 minutes. Despite our slow start we picked up speed in the middle of the course getting into two skirmishes with other groups along the way.
Because of the guess-and-check nature of the navigation method used, we often found ourselves veering from our intended path. As a result, we ended up having to backtrack up and down steep slopes and walk in large arcs to avoid drastic changes in elevation. It was less work to set up the geodatabase and load it onto the GPS unit than it was to manually plot points and calculate bearings like we did in Field Activity # 10. However, when it came to actually doing the navigation, the compass and map were more helpful. Using only the GPS unit was time consuming due to all the backtracking and course adjustment that was necessary. While with the compass and map, we had a clear direction of where to go next.
Figure 3: A map showing the locations of flags as provided for the class in yellow and the GPS locations collected in the field by Group 3 in green. The points match up very well for flags 6, 8, 9, and 13, moderately well for flags 2, 3, 4, 5, 10, 11, and 12, and poorly for flags 7, 14, and 15.
Conclusions
This activity is a prime example of how "older" techniques can be more useful then newer technologic solutions. Using only the GPS unit made navigating the course more time consuming then needed and ended up being incredibly tiring. Taking the proper time to accurately calculate bearings for use with a map and compass made navigating a portion of the course relatively simple and quick. One way the GPS unit was better then the map and compass was that we could actually tell if we were close to a flag or not. Naturally, the conclusion here is that using a map, compass, and GPS unit together to preform the navigation course would be ideal.
Sources
UWEC Department of Geography and Anthropology
UWEC Geospatial Field Methods Class Spring 2014
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