Making GCP's

Introduction:

Ground controls points are panels that are set on the ground of a site that is going to be flown with a UAS.  These panels are marked with a highly accurate GPS and the point locations are then put into the image processing software.  The points are then matched with the imagery and optimized.  This weeks the class physically created GCP panels from scratch.

Process:

The process started with cutting equally sized squares from sheets of black polyurethane.  These squares were then painted to have a two tone look with an easily identifiable center.  The GCP's were also numbered and painted on accordingly.  This process went very fast with around 14 people helping.    

The first step after cutting the sheets of polyurethane was to use a stencil to spray paint a pattern that allows for the middle to be easily identifiable.  This is important when processing the data.

A high visibility pink paint was used to break up the black surface.  A high visibility yellow paint was then used to number each GCP.  This will come in handy when tying the imagery down in the processing.

In the end the 16 GCP's were created.  The image below shows the finished product.

GCP's are important tools to tie down imagery to where is actually is on the earth.  Creating GCP's is easy, cheap and allows for highly accurate data. It is a necessary step to do when taking UAS data.