Navigating with a GPS Unit

Introduction

            The ability to navigate easily in an unfamiliar area or region is made possible through new technology such as a GPS. This instrument allows people to pinpoint their location and navigate to the location that is desired without needing timely preparation that is associated with a map and a compass. This week’s activity called for the class to divide in the same groups and navigate to 5 different points in the Priory property using a GPS unit. At the end of this activity, three maps will be produced and display my individual track log, the group members’ track logs, and all of the track logs from the class together. This report will include a breakdown of the methods, the resulting track log maps, and how this navigation technique differed from the one that was used a week prior with the compass and map.

Methodology

            The first method is to check out a Garmin etrex legend H GPS unit from the geography department at the University of Wisconsin-Eau Claire. This GPS instrument provides accurate coordinates of where the person holding the device is located. Once the GPS is obtained, it is important to learn how the track log function works on it before going out into the field. To get to this screen, turn on the device by pressing the on button located on the right side and second one down. Next press the top right side button twice to get to the track log screen where it gives the option to turn the track log on. Any stored track logs in the device from previous users should be erased so it shows only the data for the navigation activity. The track log should also be turned on once the group arrives to the starting point of their assigned course in the study area.

            The second method is to navigate to the starting point of the course that the group was assigned. Since my group did course 2 last week, we had to navigate through course 3 this week denoted with a “b” after each number in Figure 1. Finding the starting point was not an easy task as our group was provided with a GPS and a list of coordinates in UTM that we had to navigate to. Fortunately, the GPS is also equipped with a compass screen, which helped us decide the direction of travel our group needed to move in order to reach the desired coordinates on the list. The group noticed that as one moved to the east, the X UTM coordinates increased and the same occurred with the Y UTM coordinates as one moved to the north. Ultimately, we decided to focus on getting to the Y UTM coordinate first and then move east or west to the X UTM coordinate depending on our location from that point. Once the group reached the last point on the list (6b), we turned off the track logs on the GPS.

            The third method is to upload the track log points as UTM NAD 83 in the DNR Garmin program. These points can then be imported to a Geodatabase in ArcMap as a point feature class and projected to NAD 83 UTM zone 15N if necessary. ArcMap is used to show the path of the track logs on a map of each individual group in the class.

            The last method is to create three maps showing all of the class track logs from the exercise. Figure 1 shows my individual track log (track log 27), which follows course 3 going from 1b-6b sequentially. Figure 2 includes the track logs of my group on the same course. Lastly, Figure 3 displays the track logs for the entire class and covers all three courses in the study area.

Figure 1: Track Log 27 Course 3

Figure 2: Group 3's Track Logs Course 3

Figure 3: All Geography 491 Field Methods Class Track Logs

Discussion

            Although navigating with a GPS unit may seem easy and simple, there were still some obstacles that we faced during the exercise. The GPS did not provide the group an aerial view of the study area or an idea of what type of terrain changes there were in between each point. We knew that if we moved in one direction, the coordinates would go up or down on the device, but one of the major challenges was trying to make both numbers match up when navigating. With the compass and navigation map, our group had a better understanding of what direction to navigate while also knowing what terrain the destination point would be located.

            There were other obstacles that we encountered during our navigation with a GPS unit exercise that affected our movement to each point. It had just snowed the day before we went out to the field and there were fairly deep snow drifts in the Priory property along with thick forests shown in Figure 4. As a result we had to move around these areas even if our GPS read that we were moving in the wrong direction away from the destination point on course 3.

Figure 4: Deep Snow Drifts Encountered During Navigation Exercise

Conclusion

            The goal of this activity is to be able to navigate using a GPS unit at the Priory property in Eau Claire. Although this method was not much faster than other navigation techniques such as the one our class did a week prior with a navigation map and a compass, it is important to have a understanding of how technology works and can be used in the field without much preparation. I have taken a lot out of this experience by learning how to use a GPS unit to navigate and reach a specific destination on a large parcel of land.