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Ground Sample Distance Calculator

Formula

The formula to calculate the Ground Sample Distance (GSD) is:

$GSD = \frac{A \times SH}{FL \times IH}$

Where:

$GSD$ is the ground sample distance (cm/pixel)
$A$ is the altitude (meters)
$SH$ is the sensor width/height (mm)
$FL$ is the focal length (mm)
$IH$ is the image width/length (pixels)

What is GSD (Ground Sample Distance)?

GSD, short for ground sample distance, is a metric used with drone mapping and surveying to relate the focal length, resolution, and camera distance from the object. Knowing all but one of any of the variables present in the formula above means a person can solve for the missing variable. The units for GSD are distance per pixel, i.e. cm/pixel.

Example

Let's say the altitude (A) is 100 meters, the sensor width/height (SH) is 36 mm, the focal length (FL) is 50 mm, and the image width/length (IH) is 4000 pixels. Using the formula:

$GSD = \frac{100 \times 36}{50 \times 4000} \approx 0.018$

So, the ground sample distance (GSD) is approximately 0.018 cm/pixel.