Lab 3: Topographic Survey

Introduction: Topographic surveys are important to the field of surveying. Topographic surveyors create X-Y-Z coordinate data (X being latitude, Y being longitude, and Z being the elevation), which planners use for various reasons (i.e. data maintenance, establishing property boundaries, etc.).

Problem/Statement: In this lab, the process of collecting survey point to create a topographic survey of the University of Wisconsin-Eau Claire (UWEC) campus, and a 3D landscape model will be addressed.

Data Collection: For this lab, we used a total station (Figure 1) to collect the data points. Total stations help obtain X-Y-Z coordinate data, which give surveyors accurate data points to process. Surveyors walk around with a prism (Figure 2), and the total station shoots out a beam to the prism, and the prism bounces the beam back, which indicates distance (Bergervoet, Powerpoint, 2018). In calculating distance, the data collector also calculates the XY coordinates using the horizontal angle on the reading. The data collector also calculates the Z coordinate using the vertical angle, height of the rod, and height of the station (Bergervoet, Powerpoint 2018).

Figure 1. An example of a total station. Taken from https://en.wikipedia.org/wiki/Total_station

Figure 2. An example of a prism. The prisms are usually attached to a long rod, with th eprism on top. Taken from http://www.galasurvey.com/DDDDDDD/html/?218.html

Data Processing: Once the data was collected, they were put into a text sheet with X, Y, Z, and description being the headings. The text sheet was imported into ArcMap, where the “add XY coordinates” function was used (Figure 3). Once the XY coordinates function was used, it created a point feature class where we took the data points. The data points were then exported into a shapefile, then the “Create TIN” function was used to create a 3D landscape model of our topographic survey (Figure 4). The “Edit TIN” function would have been used, however the landscape model seemed accurate enough for this exercise. Also, the TIN was then converted into a raster for the purpose of creating contour lines (Figure 5). 

Figure 3. The display XY data tool. 

Figure 4. The create TIN tool. 

Figure 5. The create contour tool. 

Results: The results are represented in Figure 6. The topographic survey was relatively accurate, given the amount of points we obtained. The flow of the river isn’t the most accurate; the river on the TIN is wider and more triangulated than the basemap, however the survey got the general flow of the stream. Overall, the TIN got the general idea of the campus mall X-Y-Z representation, however with more data points it could have been more accurate.  

Figure 6. The topographic model, represented as a TIN