Drone GSD Calculator
Ground sample distance in cm/px from sensor width, focal length, altitude and image width — with the footprint your camera covers.
GSD = (sensor width × altitude × 100) / (focal length × image width). It's the resolution contract behind every mapping quote — fly too high and the deliverable can't show what was promised.
Formula per standard photogrammetry references (e.g. Pix4D/ASPRS guidance). Halve the altitude to halve the GSD.
With your numbers: A 17.3 mm sensor at 12.29 mm focal length, flown at 100 m with 5,280 px width, gives a GSD of 2.67 cm/px and a 140.76 m wide footprint per image.
⚠️ Not for operational decisions. This is a record-keeping and planning aid only — not certified avionics, not a source of regulatory truth. Always verify against official sources (FAA) and your operator's approved documents before flying.
Free GSD calculator for drone mapping: sensor, lens, altitude and image width in — ground sample distance and footprint out. The number every photogrammetry deliverable is quoted, flown and disputed on.
About Drone GSD Calculator
Ground sample distance is the resolution currency of drone mapping: the real-world size of one pixel on the ground. Clients specify it ('1 cm/px orthomosaic'), flight planning derives altitude from it, and disputes get settled by it — because crack detection, volumetrics accuracy and map scale all chain back to GSD. The formula is fixed optics: sensor width times altitude, over focal length times image width. This calculator runs it live with your camera's real parameters, returning GSD and the per-image footprint that drives line spacing. Run it before quoting (can your platform legally fly low enough for the promised GSD?) and before takeoff (does today's altitude deliver the contract?).
How to use Drone GSD Calculator
- 1Enter your camera's sensor width, focal length and image width in pixels.
- 2Set the planned altitude AGL.
- 3Read GSD and footprint; adjust altitude until the deliverable spec is met.
Why use Drone GSD Calculator?
- ✓The standard photogrammetry GSD formula, computed live
- ✓Image footprint width — the input to line-spacing decisions
- ✓Works for any camera: enter your sensor's real geometry
- ✓Quote-checking: verify a promised GSD is flyable within altitude limits
- ✓Instant, free, browser-only
Frequently asked questions
What GSD do common drone deliverables need?+
Working figures from industry practice: 2–5 cm/px for general site orthomosaics and earthworks volumetrics, 1–2 cm/px for detailed inspection mapping and crack documentation, sub-1 cm/px for facade and structural detail (usually flown close-in, not nadir). Survey-grade absolute accuracy then depends on control (GCPs/RTK), but no amount of control recovers detail the GSD never captured.
Why does my achieved GSD differ from the calculated one?+
Terrain: the formula assumes the ground is at the altitude you entered. Flying 100 m above the takeoff point over ground that rises 30 m gives you 70 m AGL and a finer GSD there — and coarser over valleys. Terrain-follow flight modes hold AGL (and GSD) constant; without them, calculate against the highest terrain in the block to guarantee the spec is met everywhere.
Does GSD equal accuracy?+
No — GSD is resolution (what detail exists in a pixel); accuracy is georeferencing (where that pixel sits in the world). A 1 cm/px map can be 50 cm off absolute position without control, and a 5 cm/px map with good GCPs can be survey-defensible. Quotes should state both numbers separately; conflating them is the most common photogrammetry contract dispute.
What happens to my entries if I clear my browser?+
Clearing site data deletes locally stored entries — that's the price of a genuinely private, server-free design. Protect yourself with the one-click CSV download before any cleanup, OS reinstall or device change: re-importing history later beats reconstructing it from memory.
Can I export these records for an audit?+
Yes — one click exports your complete GSD plan as a CSV file that opens in Excel, Google Sheets or Numbers. The export preserves every column exactly as entered, so you can print it, attach it to paperwork, or hand it to an inspector, buyer or insurance underwriter as a supporting summary alongside your official records.
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