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.      

                         

Navigating with a Map and Compass

Introduction

            Navigating with a topographic map and a compass requires a lot of preparation and accurate measurements. Today people have the benefit of technology such as the GPS to depend on for navigation; however sophisticated instruments such as this cannot always be relied on. After creating the navigation maps of the priory from last week, the class went to visit the Priory site on the south side of Eau Claire to put the maps to use. The instructor gave each group of three a series of 5 waypoints in UTM coordinates to manually plot on the maps. Each group had to pick the two best maps between the members to use for the navigation exercise—one with the 2 meter contour line interval and the other displaying the 5 meter contour line interval. This report will include a breakdown of the methods and what parts of the maps worked and what parts did not.

Methodology

            One of the most important parts of navigating is making sure the grid coordinates on the maps are in UTM so that distance can be measured when doing the exercise. The study gave the class an opportunity to work in groups of three and navigate to five specific locations in the Priory using a map and compass. This project is laid out in the following methods: gather the navigating materials, plot the points on the map, find compass bearings between each set of waypoints, measure distance between each point, discuss and assign the roles for each group member in the field, go out and collect punches at each waypoint with the group.

            The materials needed in the navigation activity include the following: magnetic compass, 5 meter contour lined map, 2 meter contour lined map, punch card, and the list of waypoints for the assigned course. Since the points provided by the instructor are in UTM, it is essential to have the grid coordinates in UTM on the navigation map. One of the maps that the group picked did not have these coordinates making it useless on the day of the activity. Fortunately all of the other groups had UTM coordinates on their grid and my group was given a usable map for the navigation exercise. The class was also given a refresher on how to use a magnetic compass for navigating in the field.

            Once the materials are gathered for the navigation exercise, the waypoints can be plotted on the map according to their given UTM coordinates (Figure 1). The instructor created 3 courses around the Priory property for each group to go out and punch in at 5 specific locations throughout study area. My group was assigned course 2, which included trekking over different levels of terrain between each point. Since the map that the group used had a 20 meter grid, each member checked to make sure that the points were accurate enough before moving on to the next step.

Figure 1: Plotting Course 2 Points on the Navigation Map

            The third method is to find compass bearings between each set of waypoints on the navigation map. Straight lines were drawn between the points so that the compass can be aligned in the exact direction of the next point on the list. Using the magnetic compass, one can take the direction of travel arrow and align it on the line between a set of points. For example, we took the compass and placed it on the map aligning it with the line between the starting point and the first point on course 2. This method was done for each plotted point on the map. We then had to move the compass house with degree dial until the “N”, which indicates north, points to the top of the navigation map. The top of the map for this study is assumed to be true north and is closely lined up with the tilted vertical gridlines. Once the “N” is pointed to top of the map, the group can look at the index line where it says “read bearing here” and record it so that it can be used to find the next point. These bearings will help us in the field once we get to a specific spot by showing us the direction that we need to face to reach the next point.

            The fourth method is to measure the distance between each point on the map using the scale bar and a piece of paper. We discovered that one of our group members has a consistent pace count of 65 for every 100 meters. Knowing the distances between each point will give us an idea how far we will need to go before looking for the landmark point on our list. The deep snow and rough terrain, which includes steep hills and thick forests, may throw off the consistent pace count making it necessary to add 15-20 steps for every 100 meters.

            The fifth method is designating the roles for each group member while navigating in the field. We had one person (me) manipulate and hold the compass according to the bearings and face in the direction of the point on the map. Since there were many steep hills and fallen trees in the way of each point, a second person (Hannah) was responsible for moving to the landmark in the direction dictated by the person holding the compass (Figure 2). This allowed for each trek between the set of points to be done in segments and ensure better accuracy in the direction of travel. Once our group member reached the landmark in the direction of the compass holder, the other person (Kory) did the pace count to that spot. Kory would add to his pace count until the group reached marker of our next point (Figure 3).

Figure 2: Group Member moving to designated landmark in the distance (dictated by compass holder)

Figure 3: One of the Markers in Course 2

            The last method is to go out with the group to navigate and collect punches at each point on course 2. This required good communication between the members to ensure that we were heading in the right direction and finding ways to overcome obstacles along the way. Both the 2 meter contour and 5 meter contour line maps were utilized in this activity because each included features that were helpful in navigating to the destination points. One map had an aerial basemap under the lines, which made it easy to tell where we were on the property of the Priory and whether or not we were getting close to a plotted point.

Discussion

            Being able to navigate with a topographic map and compass reduces the dependence on technology to do it for us. Although this navigation method is not as easy as it looks, we found that it is fairly accurate and led us to find the points on the map without too many issues. The two meter contour line map was an advantage for us in this exercise because it showed us the type of terrain in our direction of travel. Not only could we see that there was a steep hill in front of us, but the map also confirmed a steep change in elevation ahead. The aerial basemap was also beneficial to finding the location of these points by helping us see if we had to go through a dense forest of evergreen trees or around a large pond. The other advantage of our preparation before going out to field was plotting the distances we needed to travel in 100 meter intervals. This gave us an idea of how far it was to the next point while taking into consideration the pace count of the walker.

            Although there are many advantages to our navigation maps in this exercise, one disadvantage is the difficulty of being able to read the map with the 2 meter contour lines because it also included the aerial map. The next navigation map should have a more transparent the aerial map so that it is easier for even a non-geographer to read and navigate with. Another obstacle we faced while locating the points was trying to maneuver around the ponds near the freeway. Since this land feature was in the direct path of one of our points, we had to go around it and estimate Kory’s pace count once we got to the other side. The last disadvantage was our attempt to move in a straight line through the deep snow and thick forest. Even though it is winter and the trees are not filled with much vegetation, there are many fallen down logs and small trees that got in our way. We were able to overcome this by designating a visible landmark in the distance that connected with our path and have that as a meeting point before moving on.

Conclusion

            The goal of this activity is to be able to navigate using a topographic map and compass at the Priory property in Eau Claire. Although there are faster methods to navigating around an area, this method avoids relying on technology while still being fairly accurate. I have taken a lot out of this experience by learning how to use a magnetic compass and map to reach a specific destination on a large parcel of land.                      

Developing a Field Navigation Map

Introduction

Navigating in an area can be done in many different ways. This has been practiced dating back to ancient times when the Greeks would use the stars and sun to navigate around the Mediterranean Sea. Today, we have the benefit of technology such as the GPS to depend on for navigation. However, this week's assignment calls for the class to create two old fashioned field navigation maps of the Priory in Eau Claire, Wisconsin with 2 meter contour intervals and 5 meter contour intervals. The map also needs to include a localized level coordinate system because of the small study area. Next week our group will be using these maps at the site to manually plot a list of waypoints, which is provided by our instructor along with their coordinates in UTM. This report will cover the creation of the field navigation maps and the problems that were confronted and resolved during the process.

Methodology

These maps were created in ArcMap using the feature classes in the Priory Geodatabase, which was provided by the instructor. The first step is to bring in the aerial image of Western Eau Claire in the GIS and clip it to the Priory study area using the navigation boundary feature class. Having an aerial image as a basemap under the contour lines will help with the navigation exercise for the following week when the class visits the study area. The next step is to bring in the 5 meter contour lines that will go over the aerial image. Since ArcMap does on the fly projection, it is easy to forget about what the projection and coordinate systems are for each feature class. It is important to note that each feature class that was given to the class has a different projection. The 5 meter contour line feature class is projected in GCS North American 1983; the aerial image of Eau Claire has a projection of NAD 83 Wisconsin Transverse Mercator; the navigation boundary feature class has a projection of NAD 1983 UTM zone 15 North. Although all of these feature classes have a different projection, they all line up with each other in ArcMap because of on the fly projection.

When the 2 meter contour line map was created, the projection and coordinate system became an issue because none of the feature classes would overlay or match up with that particular feature class in ArcMap. The data for this feature class is based on a UWEC survey, which was converted from AutoCAD files. Since the data source for the feature class displays an undefined coordinate system, the 2 meter contour feature class has no spatial reference and cannot be lined up with the pre-existing data that have a defined projection in ArcMap. This poses a problem for navigating because the contour lines need to overlay the study area in the same projection to ensure that the results are more accurate. To fix the problem, our class started a new screen in ArcMap and brought in the clipped aerial image into the design view and then the 2 meter contour line feature class right after it. After doing this, our feature classes were able to match up with on the fly projection. If this was not done, our lines could have been significantly off on our navigation maps and give us inaccurate results of finding the exact point locations. The root of the problem is to make sure that all of the files are projected the same.

The next method is to set the grid in layout view in ArcMap for every 20 meters. The 20 meter interval will be used on the navigation map because the 10 meter interval made it too hard to read the contour lines on the map because it is so cluttered with information and lines. Going any higher than 20 meters will also make it hard to pinpoint the location of the points that need to be found in the study area.

Another important step is to set the grid to NAD 1983 UTM Zone 15 North. Using UTM coordinates for navigation makes it possible to measure distance especially for the small study area. Once this is complete, the field navigation maps can be created using the 5 meter contour line intervals and the other using the 2 meter intervals in ArcMap.

Figure 1 shows the map with the 5 meter contour line intervals. An aerial basemap is placed underneath the contour lines so that the group can find their location on the map relative to the features at the actual site. The 5 meter contour interval allows for a basemap to be included because it is not as detailed as a topographic map with 2 meter controur intervals. Figure 2 shows the map with the 2 meter contour line intervals, which does not include a basemap for the sake of reducing the clutter of detail on it and keeping its function for navigation.

 

Figure 1: Field Navigation Map of the Priory with 5 meter contour line Intervals

 

Figure 2: Field Navigation Map of the Priory with 2 meter contour line Intervals

 





 

Conclusion

                The goal of this study is to create two navigation maps using 5 and 2 meter contour line intervals for finding a list of waypoints at the Priory in Eau Claire, Wisconsin. Although some of the problems that were confronted during the process were mainly with the data all being projected differently, it is important to know the data well before working with it in ArcGIS and making sure it is all projected the same.