Assignment 10: Making Ground Control Points

Introduction

For this assignment, the task was to make ground control points (GCPs) for field use of future UAS flights. The GCPs were constructed from 4' x 8' sheets of high density polyethylene. This material was used so that if the GCPs were left in the elements, they wouldn't damage like wood or some other material. The polyethylene is also relatively cheap, heavy enough that it won't move from wind, and still lightweight enough to easily transfer to a site and place.

Methods

After all was said and done, 16 GCPs were made. The first step was to cut the sheets into 8 equal squares. This was done with a table saw (figure 1).

Figure 1: Cutting polyethylene sheet.

 After the squares were cut out, a plywood triangle template was used along with magenta-colored spray paint. The template was used twice, on either side of each GCP, to create an easily distinguishable "X" on the square. From there, a number was added to the remaining black portions of the GCP so that the GCP can be easily referenced when processing the imagery.

Figure 2: Painting the GCPs.

The GCPs were left to dry for 24 hours or so, and now are ready to be used in the field.

Discussion

Overall, the process of making GCPs with Dr. Hupy was fairly easy and enjoyable. In total, there were around 12-13 people, so probably "too many cooks in the kitchen". Nonetheless, it took around 45 minutes to make 16, good looking GCPs, so the process was fast and easy.