Lab 7/8 Topographic Survey

Introduction

The goal of this lab is to use basic topographic surveying equipment and methods to conduct a study on an area in the University of Wisconsin Campus Mall, between the Davies Student Center and Schofield Administrative Building. This lab was broken up into two major sections; the first section used the Hiper device to collect GPS field data. This section was done in a group of two where one person used the Tesla to record the points and the other person held the Hiper at the location of where the GPS point was being taken. The second part of this lab was done using the Topcon total Station and a reflective prism. This section was done using three people where one person looked/lined up the Topcon with the second person who was holding the reflective prism and the third person was working with the Tesla recording the points. Both of these exercises will teach us the basics of how to use Field Surveying equipment and also help us work with understanding different methods of collecting and exporting data.

Methods for Section 1

On the first day of working with the equipment, Dr. Joseph Hupy of the Geography and Anthropology Department at the University of Wisconsin Eau Claire taught the class how to use the equipment and delivered some tips which would prove effective once we took the equipment into the field. For this project we were going to have to gather 100 data points in the campus courtyard. This was done using four separate folders due to technical issues. In order to learn the proper way how to use the equipment which included using the Tesla and Hiper, Professor Hupy told us all the basics of how to set everything up and then instructed group 1 on how to set up all the equipment. In turn that group would then instruct the next group and so on until every group was familiar with how to use the Tesla and Hiper (image 1 and 2).

Image 1: Tesla unit used during our data collection

Image 2: Similar Hiper and Tesla unit we used during our field data collection used at an apparent construction site

The steps for this were;

                1.) On the main screen of the Tesla select the Magnet Field App

                2.) Create a new job, which is accessible from the Magnet Field Home Screen (select job)

                3.) Fill in all the information for the job. We used generic class and group names to make it                      easier for everyone to know which files were being used by which group.

                4.) Still in the new job information, several additional questions will pop up including                              Coordinate System questions and Configuration setup questions.

                5.) Using the Bluetooth capabilities, fueled by the Verizon Wireless Mi-Fi hot spot                                    (image 3), connect the Hiper to the Tesla unit.

                6.) Now we are ready for data collection. We used the code name ELEV for elevation and                        used a specific group of points so we do not experience any overlap from other groups                        once all the points are merged together.

                7.) Make sure data collection is on Fixed only. We used an average of 10 points per data                          point collection

                8.) Once all data is collected and saved, you may disconnect all the equipment and return to                       the Magnet Field home screen to export the data

Image 3: The Verizon Wireless Hot Spot, a similar model was used in the field while we were outside collecting data

While in the field collecting data one person worked the Tesla Unit while the other person made sure the Hiper, seated atop a 2 meter stand, was perfectly level while the data was being collected. Casually going through a section of the Campus Mall we collected a total of 100 data points. By hitting the save button on the Tesla Unit, it would take 10 points from the one spot and then average the points out and save it as one point. Once concluded, we exported the four files onto a jump drive. The txt file exported contained information on the northing and easting direction as well as the elevation from the point. This txt file can be imported into ArcMap and turned into a map (figure 4).

Image 4: The final product of the Hiper/Tesla data collection 

Discussion for Section 1

When looking at the map created by taking our data points we see as we move from the right side toward the left the elevation is decreasing. It is only about a 2 meter decrease but in our small study area it is seen as a large change in elevation based on the color scheme. Also as we move from the top right of the map to the bottom left we see the elevation continuing to decrease. Overall, it is clear that the campus mall is sloped downward toward the Little Niagara Creek. When looking at an aerial image of the area one would think the center circle of the amphitheater would be the lowest part, but in fact it is the area just to the east of the circle which is the lowest according to our data.

Conclusion for Section 1

In conclusion I would say that this was a fairly quick method, once all methods have been learned, to collect data. It is accurate and easy to learn. Since our study area was not done using a basic GPS tool it is difficult to say which was better at collecting data. As for the campus mall, although not a study question for this lab and something that came to a surprise to me, the circle at the center of the amphitheater is not the lowest point on Lower Campus mall, not including the land by the creek which can easily be seen as lower.

Methods for Section 2

This part of the project as mentioned in the introduction was done using three person groups. Again we spent the first part of class learning about how to use the proper equipment. To start off our learning experience we talked about what all was going to be done in the class room and learned some basics about how to use the surveying equipment and some basic terminology. Using the same study area as section 1 we had to gather 25 data points. These 25 points also include 1 backsight point and 1 occupation point.

                Occupation Point: It is the point of where the Topcon Total Station will be used

                Backsight Point: It is a point taken back towards a point of known elevation, it is used to                calculate the height of the surveying instrument.

The backsight and occupation points had to be collected using the Hiper and Tesla devices. Using the same methods as used in section 1 to collect points, the two points were collected and labeled correctly so we would know when processing the data which points were which. After the data was collected we could begin working with the total station. The first part we had to do was set up the tripod for the total station to be set up on. It was comprised of three legs with large stakes at the end of the legs to assure it would be able to stay firmly on the soft ground. Once the tripod was set up the total station could be screwed into the stand using a metal connector which screwed into the bottom of the piece of equipment. Once the equipment was at the desired height a laser was shot out the bottom to show the exact point it was above. Because we set our occupation point to a specific spot, we had to assure the laser was directly above that. Once at the correct height, we had to measure to make sure we knew the precise height of the total station above the ground. We used the elevation of 140 cm or 1.4 meters above the ground (figure 5).

Figure 5: The total Station set up and ready to be used for data collection

The next step was to make sure the equipment was completely level to assure the most accurate data collection. This was done by moving the legs up and down, one at a time, and using knobs beneath the total station. Once level we could begin collecting data. In order to collect data, the total station shoots out a laser toward the reflective prism, which is at an elevation of 2 meters.

Before shooting data points, all the equipment had to be connected via Bluetooth using the Verizon Wireless Mi-fi. This was done similar to the section 1 connection. This section proved to be the most difficult part of the exercise, will address issues in the evaluation of lab 7/8 in the assessments tab.

In order to collect the data points, one person would line up the total station view finder with the prism at a different location. Once lined up, the person working the Tesla Unit will capture the data by hitting the save file button on the Tesla, this would be done 23 times, in order to collect a total of 25 points. While working we experienced so many unable to capture data points and data points captured that we wouldn’t even have to talk instead we would just listen to the beeping sound the total station would make. A triple beep became our best friend in the frigid weather. Triple beep indicated a successful data capture.

Once all points were captured, we exported the file as a txt file, similar to how done in section one and would be used to create a 3D and a 2D view of the data.

Discussion for Section 2

The data once again put into a txt file was imported into ArcMap to create a visualization of the study area. When looking at the map created we see the elevation decreases as we move from the right side of the map to the left side. We also see as we move from the top of the map to the bottom of the map a decrease in elevation. The area around the Little Niagara Creek as expected is the lowest area in the study area, and the circle which looked like it was not the lowest point in section one, is confirmed not to be the lowest point on the map. The Occupation point was marked using a Green Flag to represent the starting point, and a checkered flag was used to mark the backsight point, not because it was the final point, but just to fit the theme of flags being used to mark the points (image 6).

Figure 6: The totalstation data captured in the field portrayed in a 2D map using ArcScene

A three dimensional map was also created, using the kriging method of data interpolation in ArcMap, a raster file was created and imported into ArcScene. In order to better see the change in elevation, I changed the exaggeration to 6.0. The image shows the higher elevation is away from the creek and as we get closer the elevation gets lower. There is only about a 3 meter difference between the highest point on the map and the lowest (image 7).

Figure 7: The 3D view of the total Station data captured, using ArcWorld to display data

Conclusion for Section 2

In conclusion I would say that this was a difficult method to learn and get used to, but once we learned how to do everything we became very quick at capturing data points. This method again if we could compare it to other methods in the same study area I could have an opinion on the accuracy, but since we did not do this I cannot say which is more accurate, but can assume this way is much more. Overall, this was a great method to be able to add to our collection of surveying techniques and like the other survey methods conducted, this one serves a particular purpose and is best suit for certain fields while other methods have strengths in different areas. 

Lab 6: Navigation with Map and Compass

Introduction

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.

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.

Image 2: The compass used to track our bearing as well as measure the distance in between the 

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. 

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. 

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.