Lab 11: GPS Navigation at the Priory

Introduction

On May 3, 2016, The class met at the university owned plot of land known as the priory for a exersize in GPS and map navigation.  Using these two tools, students podded together into groups of 3-4 and used them to navigate to a list points given to the groups by Dr. Hupy.  Before embarking out and using the GPS to find these meter based UTM locations, the group was to project the predicted locations of these points using the maps made in a previous lab, relying solely on the grid produced in the navigation lab which was conducted earlier in this course.  Once that was done, the group was to plot out the points assigned while also keeping a track record of the path that was taken en route to the points provided.  The use of tracks was intended to help the students refer back to in the difficulties they may have faced in a certain portion of their navigation.  Once complete, students returned to the parking lot and reconvened with rest of the class.  Before leaving, the groups stopped the GPS tracking session and gave the devices to Dr. Hupy.

Study Area

The Priory is located just south of the city of Eau Claire.  The property is composed of a cluster of buildings that are used as both dorms and teach facility.  Apart from the green space surrounding these buildings and the black top parking lot, the property is mostly covered in forest and other vegetation.  A majority of this forested area is on a hill which slopes down away from the priory's buildings.  Apart from the entrance road, 3/4 of the land surrounding the priory has this characteristic.  Below in figure 1 is the original navigation map that was made for the initial navigation map.

Figure 1: Priory navigation map with UTM grid (left map) and decimal degrees (right map).

As you can see by the map on the left, a majority of this surrounding land is on a major incline and is mostly forested.  As the discussion of this lab develops the difficulties of traversing this land will be discussed as it pertains to both the the topology and land cover of the area.

Overall, the conditions for completing this navigation event were very mild.  Despite a small bout of rain that lasted about 5 minutes, the conditions more or less ideal for hiking.  The wind was minimal  and the skies were partly cloudy, keeping the heat of the sun at bay.  On a personal note, a wore long sleeves and sweatpants.  This caused me to be a little warmer, but was helpful in that it protected my body from the branches, buck thorn, and ticks that were ever present throughout the navigation even. The entire process of collecting our point locations took roughly 2 hours. Let us now look at the specific locations collected by our group and the tracks that were recorded between the collection of our points.  Below, in figure 2, is a map accompanied with a series of images that show the adventure that our group embarked on.

Figure 2: Map of tracks and navigation points assigned. All pictures taken by group member: Audrey Bottolofson 

Now the challenges attributed to each point will be discussed in terms of the terrain.  Starting off with point 1: The main challenge associated with the first point was getting our bearings with the GPS.  When that was sorted out, and we could deem which way was North,South, East, and West, we took off. We knew that the location was down a sizable hill will large brush in the way, so we worked to the north and tracked back south to avoid the steepest part of the hill and the thickest part of the vegetation.   After finding that point, group member Ethan noticed that point 3 was closer to us than point 2, so we decided to find that first.  There really wasn't too much of a challenge here in terms of terrain, since we as group followed the open road with and cut back through the planted forest which presented very little obstruction from plants or hilly terrain.  The next point, point 2, had similar ease of access, but the group got a little disoriented due to a misreading of the coordinates, hence why the track indicates that the group went far south, before tracking back and heading into the forest.  The easiest point of all to find was point 4, and that was because we saw this point on our way down to the path on our way to find the first point.  Between point 4 and point 5, there was a steep hill with very thick vegetation. As such, we decided as a group that it was best to go up the path, and approach the final point from a higher vantage point, where the terrain and vegetation could be better assessed. This strategy proved to be worth it because not long after getting to the top, we were able to traverse a trail that allowed us to look down hill and spot the 5th and final marker.  Between many of these points, there was some level of back tracking and wondering to gauge the GPS unit to provide our group the necessary orientation to provide us with the correct barring to the next point. 

Methods 

To find our way through this landscape, the group made use of a Etrax GPS unit to find the way from point to point.  The main thing that we had to establish was how the numbers changed when we went certain directions.  For example,  If we went due South, we knew that the Y UTM value would decrese, vise versa if we went due North.  For longitudinal direction, we knew that if we went east, the value would decrease, and increase if we went West. As such, looking at the numbers relative to our current location, we knew the general direction we would than have to go.  After that was determined, we than assessed what obstacles would be in our way in terms of vegetation and topology as we travled, and planned accordingly as the best way to avoid these areas, without going to far out of the way 

Avoiding vegetation was especially important since 1/2 of the 4 group members were dressed in short sleeves and shorts.  Even with our best intentions of avoiding thick vegetation, the group members who wore the less covering suffered from the buck thorn and branches, and by the end of the day had their fair share of cuts. 

The group took turns holding the GPS unit and guiding the group in the right direction.  The main screen that was used during this process was a page that contained a compass and a real time update of  the GPS's current UTM location.  Taking turns, each group member gained experience working with the Etrax and continually applying a geospatil brain to thinking of current orientation/location in terms of where the group desired to be. 

Conclusion 

The experience gained from this lab was useful in that it encouraged working as a team to provide a conjoined brain of geospatial understanding.  As a team we were able to check each group member to make sure that the group was moving and traversing as efficiently as possible.  Most of the time the group was on track, but at times another member had a realizazion relative to an error being made and spoke up.  This often times saved the group allot of time since had the group continued with the same route or approach, they would have continued on in the wrong direction and would have had to spend large amount of time correcting the route and making up for time loss.