Lab 10: Surveying of point features using Dual Frequency GPS

Dr. Hupy and group partner with GPS.

Introduction:
   This week's lab centered around a simple survey method of an area. Using a high precision GPS unit, the Tesla Topcon and  the Hiper SR, (see Figure 1.) unique point

Figure 1. Tesla Topcon GPS unit used to record points.

 features were collected of several objects behind and throughout the parking lot of the Davies Center of the University of Wisconsin - Eau Claire's lower campus. Some of the objects recorded included various planted trees, lampposts and fire hydrants. With these collected points and better knowledge of the method and equipment the students each made a few maps representing the recorded data.

Methodology:

Figure 2. Simple map of survey location.

   For this activity the class was broken down into groups of two and each group took its turn joining Dr. Hupy with the GPS to collect point features behind the Davies Center. Figure 2. shows a map of the area where the data was collected. Once an object was selected to be recorded the feature is selected

Figure 3. GPS against tree about to record point.

 on the GPS before recording the point. When using the Tesla Topcon and the Hiper SR  it is important to keep the center of the GPS as close to the object being recorded for ultimate precision. The GPS had two options for recording the points (see Figure 3.). The first was the Precise option where the GPS collects at minimum sixty points where the average is calculated to intensify the accuracy

Figure 4. The original table received from Dr. Hupy

of the point collected. The second option for recording the point is the quick solution, where at least twenty points are collected and averaged. For this activity the second option for quick solution was used to record the data points. Objects recorded began in between the Phillips Science Hall and the Davies Center in the small Future Blugolds parking lot continuing behind the Davies center and through the parking lot to the east. Once each group got a chance to record their points Dr. Hupy sent the information through a table

Figure 6. Attribute table in ArcMap.

Figure 5. Navigation to Display XY data of table.

 including X and Y columns where the locations were recording with the feature attribute associated with them (see Figure 4.). The X column represented the latitude while the  Y column was the longitude. The table was then imported into ArcMap(see Figure 5.). From there the tables X, Y data is is used in Display XY data to show its location (see Figure 6.).  A topographic base map was added before creating the map below.

Results:
   With a total of 33 various feature points there were 14 trees, 11 lampposts, 2 fire hydrants, 1 telephone, 1 mailbox, 2 campus signs and 2 garbage/recycling bins collected. Below is the map created from the GPS points and their features.

Figure 7. Map created from recorded data.

Conclusions:
This lab let students use a high accuracy GPS to take a simpler point feature data survey and work on their mapping skills. The only issue the class ran into was that while completing this lab when a tree was recorded its' diameter was also listed but the data was not able to recorded and did not make it into the system when transferred from the GPS to the computer. It would have been interesting to be able to look at the tree diameters to show more attribute data along with the points.