Continuing off of the work we did in the previous lab exercise (lab 5) the class met at The Priory, which has a University of Wisconsin- Eau Claire hall and a large forest section with several trails running through the woods. Within the woods there were several marked features which had to be located using the tools provided. These tools included a compass, a map we created with a coordinate grid overlaid on the map and a list of the point coordinates so we could located them on our maps.
Area of Interest
As mentioned earlier, the area of interest where this lab was going to be conducted was in the Priory.
Located about 3.5 miles south of the University of Wisconsin-Eau Claire's Phillips Hall (where class normally takes place) the Priory is home to the large wood section right next to Interstate 94.
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| Image 1: Priory study area located in the red box toward the bottom of the map |
Methods
Meeting in the Priory parking lot, we were given our maps which we put together the previous week and with our group, also the same from the previous week, we were to locate the five points on the map. The points we had to find were;
1: 617708.81339, 4958257.83960
2: 617930.69249, 4957346.94679
3: 617619.79970, 4958049.24309
4: 617835.30499, 4958136.93679
5: 617695.53000, 4958123.65040
All points listed above our in a UTM projection, where they are measured as distance from the origin. With this data, and the the map, we individually located the five points on our map and then compared them with the rest of the group to assure we plotted them correctly. After locating the points we were given a compass with a rotating dial which could be offset to adjust to magnetic north. Magnetic North differs from true north, luckily for Eau Claire, Wisconsin that difference is minimal. The compass had a ruler on both sides, on in inches, the other centimeters, this was used to measure the distance between the two points. Once the distance was found, we could determine how far the two points were, along with the bearing by using the rotating dial of the compass and an eTrex GPS, just in case we got lost or our point was not marked. With the distance and bearing figured out, we could calculate how many paces away they points were. Our designated pace counter had a 100 yard pace count of 63. Using a simple equation (meters x .63) we could figure out how many paces away the points were from each other.
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| Image 2: The compass used to track our bearing as well as measure the distance in between the |
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| Image 3: Plotting and measuring the points we had to find at the Priory |
Now that we accuracy plotted all the points, we were ready to go locate them. Using our designated starting location, we found our bearing we had to travel, and had our pace count which we had to go.
Every member had a role in which we were suppose to follow. One person was in charge of the compass, and making sure we were heading in the right direction. Person two was in charge of keeping the pace count. Person three was in charge of making sure we were traveling in a straight line based on the compass person's direction.
On paper this seemed pretty simple, but once we got into the woods we quickly learned it was not going to be as easy as it sounded. Our paths were blocked by dense shrubbery, meaning we would have to find an alternate way around, once we were off of our designated path it became difficult to try and figure out which way we then had to go. The steep hills and down trees also made it difficult to keep an accurate pace count.
After about 30 minutes we found our first point, located between two large slopes. From that point we looked at our map to find our second point, only to realize there was an impossible object to try and walk a straight line through, that would be a large building. Luckily we found a new place where we could start from on our map which was on the other side of the building, we calculated our bearings and pace count and took off looking for it. Eventually, about 30 minutes after we found our first point, we found our second point. The second point was not marked at all, and the only way we knew it was the correct point was because we had a GPS on us which confirmed our location to be correct.
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| Image 4: A similar GPS we used to locate our actual position to figure if we were close or not to our point. |
The last point we located, point 3, took us about 40 minutes to find, It was over 350 meters away from point 2, and again the Priory was in the way so we had to recalculate our bearing once we got to the other side of the building. Once calculated we took off looking for it, on our path there we found 3 marked trees, none of which were the correct trees (other teams points), and after using the GPS to confirm our location we found that point 3 was not marked either.
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| Image 5: One of the points we had to find, the GPS confirmed the location, the tree was unmarked |
Due to the shortness of daylight in Wisconsin this time of year, we ran out of usable light at about 5:15pm meaning we could not attempt to locate points 4 or 5. Those points were about 130 meters and 180 meters away from the previous points, respectfully.
Of the three points located, 1 was marked and two were not. There could be any number of reasons why the trees were not marked, it could have been that they were never marked, the markers could have been taken or fallen off and blown away, or it could be user/technology error. Some of those things are just out of the control of the professor and students and nothing of which could be done to ensure they were still there without having to go out there and find them.
The last part of this lab exercise was to use the GPS data which was collected by the eTrex GPS, it was doing a track log the entire time we were searching for points, and use that data to create a map showing where the 5 points were and also what the path we took was.
The map shows that we took a very wrong way to find our first point, the slope and vegetation had a large part to play in that. As for the second point, it shows that we were going in circles trying to locate the unmarked tree, thinking it was a marked tree. Lastly, the third point showed very similar traits to the second point. Points 4 and 5 were not attempted due to the the early sunset.The points are assigned by elevation, As the color scheme goes from green to red elevation gets higher.
Discussion
From what was learned in this lab we can say it is much easier to navigate with a GPS at your expense, but if one is not available, or you are in an area where it does not work or it simply broke/lost being able to navigate by compass and navigation maps is an important skill to know. The map we used for this lab did have a downside to it, it used 5 meter contour intervals, When looking at some areas of the map, they did not appear to be as steep as they were in person, personally I would decrease the range of the interval to maybe 2 or 3 meters just to avoid having to climb a steep slope that does not look as steep on paper. Other then that, the maps worked great, the interval between grid lines did not cause any major problems, the imagery used was a little out of date, but not much you can do about that and the trees not being marked, again is something that is out of your control and nothing can be done to assure everything is properly marked.
Conclusion
Overall this lab was both good and bad. It was good to learn how to use the tools provided and learn how they can come in handy, but this lab also had a down side. The Priory, although a beautiful location, may of been more harmful then good due to its large size, rolling landscape and extensive vegetation that made walking in a straight, or relatively straight, line impossible to do.
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