In aerial mapping applications, the Ground Sampling Distance (GSD) represents the distance, measured on the ground, between the centers of two adjacent pixels within a digital image. For example, an image with 5cm/pixel GSD means the locations of two consecutive pixels are 5cm apart on the ground.

Remind that:

• A higher GSD indicates that less details will be visible from the images since the resolution is lower ("higher GSD => lower resolution")
• GSD is an indicator for the area represented by one pixel. For example a 2cm/px GSD means a pixel accounts for a ground area of 2 cm x 2 cm = 4 cm2

The GSD information, in a Alteia project where a photogrammetry process was conducted, it is indicated on the Photogrammetry Accuracy Reports‍.

In the example below, the average GSD was 1.7 cm/pixel: