Zerdly

Image Footprint Calculator

Ground width, height, area and diagonal of one photo — from GSD and pixels or from camera and height — with orientation-aware along/across labels.

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How to use this calculator

Inputs

Ground width, height, area and diagonal of one photo — from GSD and pixels, or from the camera and its height.

Pixel size

Leave blank for equal-scale (square) pixels. Entering a value UNLINKS the axes.

Image
More options
Orientation

Changes the along/across labels only — the physical footprint and area are the same.

Compare with a site

Enter the values and press Calculate.

Or load an example to see a worked result.

Top-down footprint and orientation
Shape to scale; no location
Top-down footprint and orientationRectangle of one photo on the ground with its width and height, pixel counts, flight direction and north arrow.NW = gₓ × NₓL = gᵧ × NᵧArrow = flight direction
One photo's ground rectangle: image width (x) by image height (y); the flight direction decides which side is along track.
Calculate first: a stale result cannot be exported.

Batch from CSV

One row per calculation, with a header row. Values use the units currently selected in the form above. Up to 10,000 rows; nothing is uploaded.

Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.

How to use this calculator

  1. Choose GSD-and-pixels or camera-and-height mode.
  2. In GSD mode leave the y GSD blank to link the axes, or enter it to unlink them.
  3. Enter the image width and height in whole pixels.
  4. Optionally set which image axis runs along track, a heading, and a site size to compare.

How it works

W = gₓ × Nₓ and L = gᵧ × Nᵧ (GSD in metres per pixel), or W = H × sensor width ÷ f and L = H × sensor height ÷ f. Area = W × L; diagonal = √(W² + L²).

Footprint scales linearly with height and area with its square. FOV = 2·atan(sensor ÷ 2f), and H × 2·tan(FOV ÷ 2) equals the footprint.

The footprint is one nadir photo over flat ground before any overlap is removed. It has no location and is not a geographic polygon; tilted (oblique) footprints are not modelled.

Worked example

2 cm/px, 5472 × 3648 px. W = 0.02 × 5472 = 109.44 m, L = 0.02 × 3648 = 72.96 m, area = 7,984.7424 m², diagonal = √(109.44² + 72.96²) = 131.53 m. With unlinked axes of 2 and 3 cm/px on a 1000 × 1000 px image the footprint is 20 × 30 m.

Frequently asked questions

Is the footprint the ground each photo adds?

No — it is the whole photo. With overlap, each photo adds only the photo step × line spacing of new ground; see the overlap and image-count tools.

Does upscaling an image enlarge its footprint?

No. Extra pixels from resizing do not widen the ground the camera captured.

Related tools

Explore more in Surveying, Coordinates, GIS & CAD.

Cite this tool

Zerdly. (2026). Image Footprint Calculator. Retrieved from https://www.zerdly.com/tools/image-footprint-calculator/

Tip: Enter any known values to calculate the remaining results.

Designed to run locally in your browser. Tool inputs are not intentionally stored by Zerdly unless stated otherwise.