According to a new project study published in the Ontario Professional Surveyor, aerial images obtained with unmanned aircraft systems (UAS) processed with photogrammetry software can produce data superior to that obtained using traditional methods.
McIntosh Perry Surveying, Inc. ran two surveys over the same 40 hectare property. One survey was conducted with a Trimble R8 base and rover RTK GPS units. The other survey was done with a RTK-equipped UAS and photogrammetry software. Six ground control points were used for reference.
The traditional survey created 1,800 3-D points which took a trained work crew 4 days to select and acquire. The UAS survey contained 31 million 3-D points and was obtained by a pilot in 1 hour. Data processing time was about the same. A 180-meter cross section shows how much more detail and accuracy to the actual terrain the UAS survey provides.
Without any corrections, the UAS survey produced points within a standard deviation of under two inches from the six ground control points in all three axis. Even this small amount of error could be easily removed by making corrections with the photgrammetry software.
The article concludes that UAS will shift the surveying paradigm from one where surveying is done in the field and data processing is done in the office to one where data acquisition is done in the field and surveying is done in the office.