GPS Topography Survey

Introduction:

For this weeks activity the class was asked to take different points around a study area located on the UW - Eau Claire campus. Each point was taken using a survey grade GPS device, this allowed the class to get its points to within 5 meters of the real life location. Using this device it will make it much easier to collect data in the field. For each data point taken the elevation data was taken as well using the GPS device. Using this elevation data the class will be creating a continuous surface of the study area where a map can be created using ArcMap. The most important part of creating a surface area map is to take enough data points with a difference in relief points so than the elevation in the land is noticeable on the map. This will allow the study area to be correctly represented, the sampling method is important as well. In this case the class used a random sampling method, this was most important because this would allow the study area to be best represented in terms of the difference in elevation. The GPS device was portable and took points on real world locations using a tripod that needed to be level in order to correctly take the point.


Study Area:

Below is Figure 1 which is the study area that was captured by using google maps so it doesn't correctly represent the elevation of the area.

Figure 1: The Area where the elevation points were collected by the class

Location: Area in front of Centennial hall at the University of Wisconsin - Eau Claire campus. In the middle where the statue is located.


Methods:

The materials that were used in the survey was a Tripod stand that needed to be level, a Topcon Tesla Field Controller, and a Topcon Hiper SR Positioning unit. Below are figures 2 and 3 representing the materials used in the survey.

Figure 2: Topcon Hiper SR Positioning Unit on a level Tripod used in survey for collecting the elevation data points

Figure 3: Topcoln Tesla Field Controller used to take points while using the other device to take points

These materials used a bluetooth handheld device which was able to download the data collected onto a computer. Once all of the data was collected, Professor Hupy processed the data and shared it into a temporary folder that was in the format of a text file. From there the class needed to transfer the data on the text file to an excel file so than it can be used in Arc map to create maps that represent the data taken from the study area. The final step was to create five different maps each with a different interpolation. The five different types of interpolation are IDW, Spline, Natural Neighbor, Kriging, and TIN tools.

Results/Discussion:

Below are figures 4 through 8 representing each of the interpolation tools used in this survey.

Figure 4: IDW Interpolation of the elevation data points taken from the study area

Figure 5: Kriging Interpolation of the elevation data points taken from the study area

Figure 6: Natural Neighbor Interpolation of the elevation data points taken from the study area  

Figure 7: Spline Interpolation of the elevation data points taken from the study area

Figure 8: TIN Raster created from the elevation data points taken from the study area

After looking at all of the different interpolation tools that can be used on the elevation data taken from the study area, I believe that the Natural Neighbor interpolation method is the most accurate out of all five. It does the best at representing the differences in the elevation level in the study area, other methods did a good job on this as well but not as effective or accurate as the Natural Neighbor. 

Conclusion:

I believe that this survey was an overall success, the task at hand was to collect data points from a study area selected by Professor Hupy using a survey grade GPS device. Once data was collected it was time to transfer the data in order to create maps. The overall process was simple and easy to understand, the GPS device made everything with collecting the data easier than it should have been. But is was a great learning experience and gave the class a view at what is capable using a GPS device especially one that is so accurate to real life locations.