Over the past few weeks, our Geospatial Fields Methods class has been participating in different land navigation techniques. This process began by spending the first week establishing pace counts for each person in the class and creating maps that would be used for navigation with a compass. The next week, we were put into groups and assigned six points that we were to navigate to using traditional map and compass navigation. The next field outing consisted of navigation to a different set of six points using just a Garmin eTrex GPS unit. The field outings concluded this past week with a final navigation activity that incorporated paintballing. Each group was to navigate to as many points possible with the use of a GPS unit and maps that were created.
Study Area
Our field navigation exercises took place on the lands surrounding The Priory, which is located just to the south of the city of Eau Claire. An aerial image of the area, navigation points, and 5-meter contours can be seen in Map 1.
Map 1. Study Area |
Methodology
Week 1
In preparation for the first week's field outing, we needed to establish our pace count and create the navigation maps that we were to use out in the field. Our pace count was established by marking off a distance of 100 meters and counting the number of paces it took us to walk it. I found my pace count to be 65. To create the navigation maps, data such as a orthophotograph, two-foot contour lines, five-foot contour lines, and a DEM was used. A UTM grid was also placed over the map to aid in the navigation. Each group member created two maps for the event and then as a group, two final maps were selected to use in the exercise (Maps 2 and 3).
Map 2. My map for traditional land navigation exercise. |
Map 3. Hannah's map for traditional land navigation exercise |
On the day of the field event, we plotted the locations of the points that our group was assigned to navigate to. Straight lines were then drawn from point to point, and a compass was used to measure the bearing.
Figure 1. Mitch and Hannah plotting points. |
Figure 2. Mitch standing at point marker and directing Hannah towards next location. |
The next week, we were to use GPS units to navigate to the points rather than using the traditional land navigation techniques using a map and compass. Each student was assigned a Garmin eTrex GPS unit for the activity. The unit would be used to locate the navigation points that we were assigned and to track the routes that were taken while navigating to the points. My group was assigned the points on Course 3, with point 1B being our starting point and heading to the other points in order.
Table 1. Navigation Points |
Figure 3. Hannah and I examining our GPS units at a point marker. |
Week 4
The final activity incorporated paintballing into the navigation exercise. Each group was to navigate to as many of the 18 navigation points as possible using a Garmin eTrex GPS unit and maps that we created for the event (Maps 5 and 6).
Map 5. Paintball navigation exercise map. |
Map 6. Paintball navigation exercise map. |
Discussion
Overall, the different navigation events went very well for our group. In the first activity using a map and compass, we were able to utilize a method that allowed us to move to the points quickly and efficiently. However, there were a couple minor issues that we had to overcome. The pace count that we established was done in a flat parking lot, and was not very conducive to estimating accurate distances when walking through the woods. There were many hills that we had to walk up and down, as well as many trees and other obstacles that made walking in a straight line difficult. When walking between points four and five, we came across some ponds that were fenced off. In order to accurately maneuver around them, we counted a number of paces to the side of them. Once we were around the ponds, those same number of paces were walked sideways to get back on the correct bearing. As mentioned earlier, we also the grid issue on Hannah's map that did not allow us to plot the UTM points. Experiencing this shortcoming has stressed the importance of reviewing every detail before going out in the field.
The maps that we prepared were great resources in the field. The aerial imagery was very helpful in determining what type of terrain we were in and should be going to. The DEM symbology and contours were also useful for tracking our progress on the map. We had to walk up and down a few hills, and this information allowed us to make an accurate estimate of our location in terms of the points we were navigating to. The point data we were given had the elevation in meters listed, and Map 2 that I created was useful because the five-foot contours were labeled. For future navigation exercises, I would create maps very similar to the ones that we created for this event because the information we included on them was very helpful in the field. One change would be to include the grid on both maps.
After the completion of the second field outing, it was apparent that navigation with a GPS is easier and faster than traditional navigation with a map and compass. GPS navigation does not require any preparation time, and it is much quicker in the field because a person can continuously walk and not have to worry about walking to a certain spot on the bearing and count the number of paces. It also can be accomplished easily by oneself, whereas in the traditional method, a three person group is ideal. Another advantage of GPS navigation is that a waypoint can be created on the GPS and it will tell you which direction and how far to travel to this location. We did not do this during our navigation exercise, but this would have been very helpful and effective to do.
Even with these benefits of GPS navigation, we did run into a few minor issues in the field. It was very easy to misread some numbers when walking and looking at the GPS which led us a little out of our way a couple times. An example of this can be seen in the animation of my track (http://www.youtube.com/watch?v=iP7FNiIi3xk) between points 3, 4, and 5. When using UTM coordinates, it is important to remember that the x values increase as you move to the east, and y values increase as you move to the north. A map accompanying the GPS unit can be very helpful to visualize this when determining the direction to travel. This led us to the final navigation exercise where we had a map to accompany the GPS. This method proved to the the quickest and most efficient method of land navigation. Maps 7-12 display the track log data from each of the two navigation exercises where GPS units were used.
Map 7. My track log from GPS navigation exercise. |
Map 8. My track log from GPS and map navigation exercise. A green to red color ramp was used to symbolize the time. |
Map 9. My group's track logs from GPS navigation exercise. |
Map 10. My group's track logs from GPS and map navigation exercise. |
Map 11. Class track logs from GPS navigation exercise. I was assigned to Group 3. |
Map 12. Class track logs from GPS and map navigation exercise. I was assigned to Group 3. |
Conclusion
These field navigation exercises provided an excellent understanding of three different navigation methods: traditional navigation with a map and compass, GPS navigation, and GPS navigation with the aid of a map. My group was able to successfully navigate to points using these methods, and upon reflecting on them, decide which method was the easiest and most efficient. This turned out to be navigation with a GPS and map. Navigation with just a GPS unit is not a bad option, but having a map available all the time is not very conceivable. Finally, the method of navigation with a map and compass was the slowest, but is still an effective option in cases where GPS technology is failing the user.
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