Height for a target GSD

The height above ground that gives a target ground sampling distance with your camera, checked against your altitude ceiling.

Go the other way: Ground sampling distance (GSD) →

Planning and education aid. Not for primary navigation. Full disclaimer

Computing your own values needs JavaScript and WebAssembly. The worked example below was computed when this page was built, and the documentation under "How we got this" applies.

72.96m

Fly at 72.96 m above ground for that GSD.

Footprint across track

Provenance

Computed by: drone.photogrammetry.altitude-for-gsd 1.0.0, core 0.1.0
Model: Height = GSD × focal length × image width / sensor width
Accuracy: Exact for a nadir view over flat ground
Notes: None
Cites: Wolf, P. R., Dewitt, B. A., and Wilkinson, B. E., McGraw-Hill, Elements of Photogrammetry with Applications in GIS; Federal Aviation Administration, 14 CFR 107.51, Operating limitations for small unmanned aircraft

Something look off?

Your values

Showing an example. Change anything.

Target GSD Like 2 cm per pixel · plain numbers mean cm Sensor width Physical width, like 13.2 mm for a 1-inch sensor · plain numbers mean mm Focal length Physical focal length, like 8.8 mm · plain numbers mean mm Image width Pixels across the long side, like 5472

More options 5

Sensor heightoptional Physical height, like 8.8 mm (for along-track values) · plain numbers mean mm Image heightoptional Pixels on the short side, like 3648 Focal length typeoptional physical (default) or equivalent-35mm Crop factoroptional Needed with a 35 mm-equivalent focal length, like 2.7 Altitude ceilingoptional Default 400 ft AGL (14 CFR 107.51) · plain numbers mean ft

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How we got thisFormula, worked example, sources, and proof

Model: Height = GSD × focal length × image width / sensor width

Show your work

Pixel pitch
pitch = sensor width / image width
13.2 mm / 5,472 px = 2.412 µm
Height for that GSD
height = GSD × focal length / pitch
2 cm × 8.8 mm / 2.412 µm = 72.96 m

The same steps an agent gets from the MCP server with explain: true.

Accuracy: Exact for a nadir view over flat ground

When to use this: Use this when the deliverable fixes the resolution: a client asks for 2 cm ground sampling distance, or a survey specification names one, and you need the height to fly to get it with the camera you have. It is the inverse of the GSD tool and the first number in a mapping flight plan, before overlap, spacing, and battery time.

Limitations: The height it returns is above the ground being mapped, not above the takeoff point, so terrain that rises under the flight changes the resolution you actually get. It assumes a nadir view over flat ground and an undistorted lens. Airspace and the rule you fly under cap the height regardless of what the resolution wants, and this tool checks only the ceiling you enter.

Worked example: 2 cm per pixel with a 1-inch camera. Source: add-drone-suite scenario: 72.96 m AGL. It is golden test vector v001, and every build checks the tool still gives its answer within its tolerance.

You enter

Focal length: 8.8 mm
Image height: 3648
Image width: 5472
Sensor height: 8.8 mm
Sensor width: 13.2 mm
Target GSD: 2 cm

You get

Height above ground: 72.96 m
Footprint across track: 109.4 m

Review: Not yet independently reviewed by a Part 107 remote pilot.

Last verified: 2026-09-18, when a maintainer last confirmed this tool's sources at the issuer. See the sources ledger.

Status: version 1.0.0, core 0.1.0. See this tool in the verification report.

Changes

2026-09-19, changed: Ground sampling distance and height for a target GSD are now stable. Both match a published worked example (a 1-inch camera at 120 m gives 3.13 cm per pixel) and 20 vectors each from a separate implementation. Results are unchanged. Changelog

Checked against: 21 golden test vectors (download the test vectors, each with its source and tolerance). See how results are checked and every source.

Sources

Elements of Photogrammetry with Applications in GIS, Wolf, P. R., Dewitt, B. A., and Wilkinson, B. E., McGraw-Hill, 4th edition. Chapter 6 (vertical photographs: scale and ground coverage). Read free.
14 CFR 107.51, Operating limitations for small unmanned aircraft, Federal Aviation Administration, Current as of the review date in the operations reference. §107.51(b): 400 feet above ground level. Read free. Rules as of 2026-09-18.

Terms

AGL: above ground level: Height measured from the ground directly below, not from sea level. Source: Aeronautical Information Manual
CFR: Code of Federal Regulations: The codified US federal regulations. Aviation rules are in Title 14, written as 14 CFR. Source: 14 CFR Part 1 definitions
GSD: ground sampling distance: The ground width one image pixel covers, such as 2 cm per pixel. A smaller GSD shows more detail. Source: Elements of Photogrammetry with Applications in GIS

Learn the concept: What is ground sample distance (GSD)?