Ground Sampling Distance (GSD)

1. Description

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.

2. Reminder

  • A higher GSD indicates a lower image resolution, meaning fewer details will be visible in the image ("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

3. View GSD with Alteia

3.1 On a Base Layer Raster

The GSD information in an Alteia survey is indicated on any layer in the "BASE LAYERS" section.

In the example below the GSD is 0.2 inch/pixel.

Note: the unit system could be changed with the site profile edition.

3.2 On the Photogrammetry Accuracy Report

For surveys where the photogrammetry process was launched within Alteia, the GSD information is also indicated on the Photogrammetry Accuracy Reports‍.

In the example below, the average GSD is 5,6 cm/pixel: