Assignment 7: Navigation with GPS

Introduction

This week was a continuation of the past several weeks. The class went back out to the Priory to do more navigation exercises. This time around however we were to use a GPS to navigate to our points. We also will not be added by a map. Everyone was assigned a new course to complete. This time my team did course two backward. Every student was issued a Garmin GPS unit. These units served a duel purpose. They were to help us find the points and the other was to record a track log for each student. When we got back to the lab we would use the track logs to create three different maps, a map with just our track log, one with our whole team and one with everyone's track log. The Eau Claire area had just experienced a snow storm earlier that day. There was still some snow flurries when we started out.

Methods

The class met up at the parking lot at the Priory. We were issued a Garmin GPS unit and taught how to record a track log. A track log takes continuous point data that can be used to show a persons path that they took. We were also given the coordinates of a new course. This time my team did course two in reverse. Point 1 is the starting point. From there we went from points 6-2 and then back to 1. We did not have our entire group with us this time. Drew came late after me and Stacy had started the course. Drew caught up with Team 1 and so did the course from 2-6 instead of 6-2. This means his track log will look different from ours so that the team map will look odd.

The Garmin GPS uses UTM eastings and northings to show where on earth a person is. Figure 1 shows a picture of our GPS with it showing the UTM coordinates and a compass. It took me and Stacy a little while to get used to navigating with the GPS units. We ended up going in the wrong direction for a while before we got on the right track. It was a little difficult to figure out in what direction we had to walk in to get the numbers to do what we wanted. At the end of the course we stopped our track logs to complete our paths. We would download the information later back at the lab.

Figure 1: This is our Garmin etrex that we used for this activity. The UTM coordinates are shown at the top of the screen.

In the lab we downloaded the track logs using the DNR Garmin software. We made a point feature class of our track log and put it in a class geodatabase. This way we all had access to each others data to make our maps. We made point features because you can do better analysis using points then with lines. For example you can map out the time field and color the points to show in which direction a person walked. This is what I did in Figure 2. Figure 2 shows a map of my individual track log. The points go from green to yellow to red depicting where I walked when.  Looking at the map you can see it took me and Stacy a little bit to get used to the GPS units. From point 1 to point 6 we started out going in the wrong direction in the beginning. What the map does not show is that we headed down a really steep hill before we figured out we where going in the wrong direction. So it turned out we had to climb back up the hill we just went down.  From point 5 to point 4 we had to navigate around a pond so we could not go in a straight line but had to take a detour.

Figure 2:  A map of my individual track log.

The next map we had to make was a map of our team. Figure 3 shows our team map. Stacy and my tracks line up pretty well. Drew's on the other hand does not. This is because he showed up late and we had already started the course. Drew ended up doing the course with Team 1 who was on course 2 as well. They however were doing the course forward. So Drew's track is going in the opposite direction then ours.

Figure 3: Our team map.

The last map we were to make was one of every students track log. Figure 4 shows a map of every team withe the courses we each did. This time I did not map out the the time attribute of the track logs. Instead to show the different teams I made the points one color so to distinguish the different teams. All the odd numbered teams did their course forward while the even teams went backwards.

Figure 4: A map of every student. The students track logs are color coded depending on which team they were on.

Discussion

I found this activity much easier then using the map and compass. It certainly went a lot faster then the last time when we used the map. When using the map and compass you need to be in a group of a bare minimum of 2 or 3. It is important to have a person to count the paces, one to go ahead of the group and one to hold to compass and instruct the person out front to line up with the azimuth reading. Before heading out you need to plot the points on a map, get the azimuth between the points and the distance between the points. With the GPS units a person could navigate by themselves. All they would need was the coordinates of where they wanted to go. There really is now preparation to do before heading out like there is with the map and compass.

Like I mentioned in the introduction Eau Claire had just got dumped on by a snow storm. We had around 6in of new snow on the ground added to what was already on the ground. For most of the course me and Stacy were walking in snow all the way up to our knees. In some parts of the courses we were walking on the sides of ridges that were very steep and slippery. Me and Stacy ended falling in several places along those ridges. To get to point 5 we had to walk through a large stand of pine trees. These were much easier to walk through because the pine branches caught a lot of the snow, meaning less accumulated on the ground. Figure5-6 show how the deep the snow.

Figure 5: Stacy standing in the snow checking our coordinate

Figure 6: Me standing out in the snow. This was taken in the stand of pine trees. Here we tried to stay under the pines as much as possible because the snow was not as deep as other places like up above.

Results

This week's activity and last week's was to show us difference between traditional navigation(map and compass) vs. GPS navigation.  I believe that it did a very good job of showing the strengths and weaknesses of each method. While the GPS made it easier and faster to navigate, there could be a point when the GPS could not hook up with the satellites.  The traditional navigation does not relay on technology. It can be done anywhere, anytime, in any weather. The downside is that it takes longer to prepare, need to be in group of 2-3 and takes longer than the GPS navigation. Both methods a perfectly viable just depends on the situation you find yourself in when deciding which one to use.






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