GSD Calculator
Calculate Ground Sample Distance (cm/pixel) and image footprint for drone / aerial mapping. Pick a drone preset or enter your sensor specs.
GSD = (sensor width × altitude × 100) ÷ (focal length × image width). Assumes a nadir (straight-down) shot.
About the GSD calculator
Ground Sample Distance (GSD) is the real-world size of one image pixel on the ground, usually in centimetres per pixel. It's the key number in drone mapping and aerial survey: a lower GSD means sharper, more detailed orthomosaics. GSD depends on your camera sensor, lens focal length, image resolution and flight altitude.
How to use it
- Pick a drone preset, or enter your sensor width, focal length and image width.
- Set your planned flight altitude (above ground level).
- Read the GSD, ground footprint and the altitude needed for 1 cm/px.
Frequently asked questions
How is GSD calculated?
GSD = (sensor width × flight height × 100) ÷ (focal length × image width), giving cm/pixel for a nadir (straight-down) shot.
What GSD do I need?
General mapping often targets 2–5 cm/px; detailed inspection or stockpile work may want 1 cm/px or finer. Lower GSD means lower altitude and more images.
Does this account for camera tilt?
No — it assumes the camera points straight down. Oblique angles increase GSD across the frame.