GIS4930 - Module 1.1 - Spatial Data Quality

In this module, we were tasked to explore GPS accuracy and precision using waypoint measurements. We worked with GPS waypoint coordinates collected at the same location and converted them into point data for mapping and then calculated the average position of the points and determined the radius needed in a series of ringed buffers to capture 50%, 68%, and 95% of the waypoints. After creating our buffer rings, we compared our average waypoint to a surveyed reference point to evaluate the relative accuracy and precision of the measurements.

Horizontal precision measures how close repeated measurements are clustered together, while horizontal accuracy measures how close those measurements (or their average) are to the the reference location.

 

My results showed that the horizontal precision of the GPS points was 4.5 m, and the horizontal accuracy compared to the reference point was 3.24 m. This shows that most of the points fell within about 4.5 meters of the average location, and the average itself was only 3.24 meters away from the true surveyed position, meaning the GPS data was fairly close to the surveyed benchmark.