Photography Calculators

Timelapse & video

Drone Mapping Overlap Calculator

Mapping is aerial photogrammetry with a grid. Footprint is altitude times sensor over focal length. Spacing is footprint times (1 − overlap). Photo counts are ceil(area / spacing) plus one, then multiplied. GSD is the footprint width divided by the image width in pixels — use the stills resolution, not a video mode. Fly a short test line before the whole field.

Inputs

Units
m

Height above the ground you will map, not AMSL. Imperial shows feet.

mm

Actual focal length of the mapping camera, not 35 mm equivalent.

mm

MFT-class drones are often ~17.3 mm wide. Mini 1-inch sensors are smaller.

mm

About 13 mm on Four Thirds, 8.8 mm on a 1-inch sensor.

px

Pixel width of the saved stills, e.g. 5280 on a 20 MP Four Thirds drone.

m

Side of the rectangle you fly along. Imperial shows feet.

m

Side of the rectangle across the flight lines. Imperial shows feet.

%

80% is a common mapping default. 70% is lean; 90% is dense.

%

70% side overlap is typical. Raise it on 3D sites with buildings.

Results

Footprint width
57.67m

Ground width of one frame on flat ground at this altitude.

Footprint height
43.33m

Ground depth of one frame along the flight line.

Photos along-track
25

Shots per flight line, including one extra end frame.

Photos across-track
10

Flight lines across the site, including one extra edge line.

Total photos
250

Photos along × lines across. Plan battery and card separately.

GSD
1.09cm/px

Ground centimetres per pixel: footprint width ÷ image width × 100.

The Result is indicative and educational. It does not constitute a design, a technical opinion or medical advice and does not replace calculations or verification by a person with the appropriate qualifications and authorisations. Before purchase, installation or use in practice – in particular in electrical installations – the Result should be verified by a qualified specialist. Details: Terms of Service, point 4.

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Calculation method

Ground footprint width is altitude times sensor width over focal length (same units game as field of view). Height uses sensor height. Forward spacing is footprint height times one minus front overlap; side spacing uses width and side overlap. Along-track photos are the ceiling of area length over forward spacing, plus one for the extra end frame; across-track is the same with area width. Total is the product. GSD in cm/px is footprint width in metres divided by the image width in pixels, times 100 — the same as altitude × pixel pitch ÷ focal length.

Exact formula

footprint = altitude × sensor / f. spacing = footprint × (1 − overlap/100). photos = (ceil(area/spacing)+1) along × across. gsdCm = footprintW / imageWidthPx × 100. Limits: Terrain, gimbal tilt, wind, lens distortion and RTK omitted; overlaps must be under 100%.

Wind and terrain

Hills shrink AGL on the upslope and grow footprint in the valley. Plan for the highest ground in the site or you will punch holes in the mesh.

Battery vs photo count

Total photos is not flight time. A 200-photo grid at 2 s interval is still a short flight; transit, climb and extra lines for wind are the real budget.

Frequently asked questions

Which image width?

The pixel width of the stills the drone saves: about 5280 px on a 20 MP Four Thirds camera, about 5472 px on a 20 MP 1-inch camera. Do not type a video resolution — 4K video is 3840 px wide and gives a coarser GSD than the stills.

Nadir only?

Yes. A 45° oblique grid is a different footprint. Keep the gimbal at −90° for this math, or the overlap you typed is a lie.

Legal altitude?

This tool does not know your aviation rules. Stay inside the local cap even if GSD wants 120 m.

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