GSD Accuracy in Photogrammetry

What is GSD (Ground Sample Distance)?

GSD represents the real-world distance between the centers of two adjacent pixels in a digital image. A GSD of 1 cm/px means each pixel represents a 1x1 cm area on the ground. Lower GSD values signify higher resolution and more detailed models.

Volumetric Error Analysis: Traditional vs. Photogrammetry

While traditional RTK-GPS/Total Station surveys offer millimeter precision, they are time-consuming and costly for large areas. UAV photogrammetry can scan vast terrains in hours. Our research indicates that a model produced at 5 cm/px GSD can have a volumetric error (RMSE) of 2-5% compared to ground surveys. By decreasing the GSD to under 1 cm/px, this error margin can be reduced to less than 0.5%, representing significant cost optimization in large-scale stockpile or earthwork calculations.