Field Activity #4: Conduction a Total Station Survey

Introduction

For this experiment, a survey was conducted within the campus mall of the University of Wisconsin – Eau Claire using a data collector and total station. Throughout this survey, we used the established control points, provided by the Eau Claire County Surveyor’s Office, and collected X, Y, and Z topographic points on campus. The area that we surveyed had relatively low topographic relief as well as a few planted trees and dolomite blocks to sit on provided by the university. The purpose of the experiment is to create a landscape model, using the TIN feature, of the UWEC Campus Mall using the X, Y, and Z points gathered.

Methods:

October 9, 2019

Sunny, ~ 21.3 degrees Celsius

After an introduction to the nature of the survey and the equipment we would be using, we headed from Phillips Hall to the UWEC Campus Mall. Our survey took place within the area below:

The equipment we used throughout this experiment included the data collector, dual frequency GPS unit, and the TopCon GPT Total Survey Station. Both tools were used to maintain data accuracy. Through using these two different methods, we had generated the same results. This allowed us to compare the methods used and which equipment is best suited for a given job.

The first tool that we used was the data collector, the HiPer GPS/ Tesla Handheld System as well as the dual frequency GPS unit. The tripod allows for leveling and allowed for a more accurate point. When taking each point, we averaged about 1 point every 50 feet for this exercise. It was important to listen to the instructor and the Surveyor’s instructions as we went through this process.

To start collecting data, you first start a new “Job.” This can be found by clicking on the “Job” icon and then renaming your file with a name. Next, when selecting “Edit” I manually entered the control point coordinates. In the field, select “Set Up” to orient the instrument. Select “Survey,” then “Topo” to start collection your X, Y, Z points.

The second method that we used was the T TopCon GPT Total Survey Station. This tool had to be set up at a leveled location before the points could be collected. This instrument was mainly used to measure the sloping distance of an object to the instrument, horizontal angles and vertical angles. The Total Station is an electronic/optical instrument used in modern surveying. This tool operates and collects data using an electronic transit theodolite along with an electronic distance meter (EDM). The data collected from this station can then be downloaded to the computer for further processing.

Using the established points provided by the Eau Claire County Surveyor’s Office, we collected the points automatically.  These points are entered into the data collector, and therefore, would be our zero-calibration line at 0⁰0’0’’. When taking a point, the total station then sends out a beam and the prism bounces it back. The instrument then takes the horizontal angle into account, and automatically calculates the correct XY location of the point of interest. The vertical angle is calculated by the data collector and takes a ground elevation point.

Results:

After completing the survey, the points are then processed by the Eau Claire County Surveyor’s Office and sent back to us (as it is their equipment we used). The CSV file with the X, Y, and Z coordinates is then imported into ArcMap using the “Add XY Data” function, converting into a 3D point shapefile.

Next, I created a TIN model in ArcMap and edited the collected points. I then generated 2-ft and 1-ft contours using the TIN and “Contours” tool to create my final result. Within this map, I have also added the surveying points that were taken using both methods.

Discussion:

Through Total Station Surveying methods, there is a relatively easy and quick data collection process involved. When taking the measurements, it was relatively easy and efficient. However, although gathering information proved to be a breeze, the coordinates were gathered calculated on a rectangular grid system, and not taking into consideration the curvature of the Earth. The rectangular coordinates must be transformed into the correct geographic coordinates when projects are larger scale.

Conclusion:

During this experiment we used a few expensive surveying equipment when gathering our data during this survey, however, it’s important to keep in mind that using higher quality equipment doesn’t always mean that there will be no error or malfunction. Equipment that needs to be charged before using, could become useless if the equipment no longer works. In addition, if equipment is slow in the field, it could put a strain on a day in the field when working on a project. Overall, the purpose of this experiment was to familiarize ourselves with using tools in calculating spatial relations with coordinate systems and professional surveying equipment. These methods are useful in accessing accurate and precise data when surveying an area within the field.