Ground Sample Distance (GSD) (also known as Resolution)

This is the distance between the centers of the pixels measured at the ground. Manned aircraft generally obtain GSDs in the range of 25 – 50 cm/pixel. sUAS being restricted to an altitude of 400’ have much higher GSD in the range of 1 – 3 cm/pixel. The GSD required will depend on the requirements of the job. A data acquisition firm must obtain this parameter prior to flight. It is best to operate the drone at the maximum altitude allowable which is 400’ which provides about 3 cm/pixel GSD (camera dependent). This is usually more than adequate for most jobs. A better GSD may be required for estimation of piles of materials or open mines.