Lab 8: Topographic Survey of UWEC's Southern Portion of Lower Campus

Introduction 

For this lab exercise, students were paired into groups of two to conduct a topographic survey of the University of Wisconsin Eau Claire's Lower Campus.  During the lab, groups took turns going out onto the campus mall with Dr. Hupy to take point locations of a combination of lights, trees, garbage cans, or bike racks.  To take these measurements, a highly accurate Top-Con survey grade GPS device was used to create these point features.  The partner that I was to conduct my survey with was Andrew Faris, and we were the the 5th group of 6 to go to the field and conduct a survey.  Once each group has collected their points, the class was then to combine the data collected from all the groups into one, complete dataset, and export the data into ArcMap where it can be converted into a features that represent the totality of what the class collected. 

Study area and Methods 

The Area where this Activity was conducted was on the lower campus of the University of Wisconsin of Eau Claire, in and around the parking lot that is located to the south of both the Phillips Science Building and the Davies Center.  The device which was used to collect the features in this area was a TopCon Survey Grade GPS unit.  In past activities, GPS units were used that provided accuracy that could be off by a meter or more when pinpointing locations.  The TopCon utilizes RFC technology that can provide sub centimeter accuracy. 

This device comes with a complete built in interface that allows for the user to manipulate the data being collected in the field in real time.  Apart of this interface is a reassembled set of field attributes that identify the point of which is being identified with the device.  By doing this, exporting the data into a GIS software program becomes very symbol, and essentially only requires that you bring it into a geodatabase, provide appropriate symbology, and than make/publish the map the document that shows the location and desired attributes of each feature. 

Collecting the point locations was very similar to using a small handheld unit or cellphone, except for the fact that the TopCon set up is much more bulky.  The device from which the user selects the inputs and other options is a Tesla unit that is about 8 inches wide and 4 inches high.  The Tesla device is portable, but during survey operations it is mounted to a tripod.  Atop the tripod is a the GPS device, which is securely mounted to a long pole with a fixed l.  The GPS atop and the Tesla communicate via a MiFii device which is connected to the 4G network.  Figure 1, below, shows the full set of components that were used in this field operation. 

figure 1: Top Con Survey Grade GPS Unit

The GPS unit atop takes the point location from the geographic or projected coordinate system specified by the user prior to the beginning of survey activity.  The x position, Y position, and Z (elevation position) are taking from the point where the middle black pole in the middle meets the surface below.  The other two poles, seen in figure 1 as the poles colored a bright yellow color, provide support as steaks that can penetrate the surface if the ground material a soft material.  Using these three legs, the users need to adjust the legs until the device is level.  To aid with this process, the tripod is equipped with a bubble leveler near where all three legs meet.  Doing this helps assure that the GPS unit collects the most accurate point possible.  

Collecting the point is a very simple process as well, All that one needs to do is select the feature they are mapping, using a touchscreen pen.  Once you have a feature type selected, and have a confirmed GPS fix from the satellites above, a point can be taken with the simple push of a button.  Collecting a point can be done by simply having the device take a single point, or by taking the average of a specified number of readings.  In the instance of this lab acclivity, the point that was recorded was recorded as an average of 30 points per feature identification.  This was not done in this activity, but the Tesla station also allows the user to take a picture when taking a feature location, which would than be attributed to that point location when exported into a computer desktop. 

In terms of the collection process, this was done during a single class period on April 12th, 2016 in groups of two.  Dr. Hupy and the departments GIS technical adviser, Martin Geotell, took two students at time into the study area to get experience doing topographic work with the TopCon station.  The collection process took roughly 1.5 hours, and was a smooth and easy process since there was no inclement weather (partly cloudy at around 55 degrees F) or technical issues.  

Once the collection process was complete, the locations and attributes were provided to students by Dr. Hupy as a comma delineated text file, which was than imported into excel so that it could be turned into a table.  Once in table format, the table could be imported into a geodatabase, projected to WGS 1984 UTM Zone 15N, and shown as features using the XY tool. 

Results

Below, in figure 2,  is a map of the features collected from the topographic survery that was conducted on a April 12th, 2016 using the TopCon total station. 

Figure 2: Topographic UWEC campus survey

Conclusion 

The TopCon total station had failed on students in the past and it has since been fixed with a new and improved interface.  When functioning, it is a very smooth and intuitive tool that provides users with sub-centimeter locations of features  in a variety of geographic/projected categories.  Such a knowledge of this tool will be useful going forward working with construction based projects where highly accurate GPS data is required as apart of a project.