Work out the ground sample distance of a drone flight: pick a camera (or enter any sensor's specs), set the altitude, and get GSD in cm/px plus the image footprint. GSD = sensor width × altitude × 100 ÷ (focal length × image width).
Formula: GSD (cm/px) = sensor width (mm) × altitude (m) × 100 ÷ (focal length (mm) × image width (px)). Pick Custom to enter any camera's published specs.
Ground sample distance
1.63cm/px
In inches
0.64in/px
Image footprint width
85.8m
Survey grade; the range most stockpile volume work targets.
GSD is the resolution floor of everything downstream: contour detail, surface reconstruction, and ultimately volume accuracy. Halving your altitude halves your GSD and quadruples the number of photos needed for the same area, so the practical question is never "what's the finest GSD I can fly" but "what's the coarsest GSD that still supports the measurement."
GSD (cm/px) = sensor width (mm) × altitude (m) × 100 ÷ (focal length (mm) × image width (px))
Inspection work wants sub-centimeter GSD. Stockpile volumetrics typically target 1–3 cm/px. General site mapping tolerates 2–5 cm/px. Beyond that, surfaces smooth over and measurement error climbs. For how drone photogrammetry compares to phone scanning and fixed LiDAR for pile measurement, read our guide to the best ways to measure stockpile volume, or see our drone capture services if you'd rather have the flight done for you.
Ground sample distance is the real-world size of one image pixel on the ground, usually expressed in centimeters per pixel. A GSD of 2 cm/px means each pixel covers a 2 × 2 cm patch of ground. It's the fundamental resolution limit of a drone survey: nothing smaller than the GSD is reliably measurable.
GSD (cm/px) = sensor width (mm) × flight altitude (m) × 100 ÷ (focal length (mm) × image width (px)). Fly higher and GSD grows (coarser); use a longer lens or higher-resolution sensor and it shrinks (finer).
Most stockpile volume work targets roughly 1–3 cm/px. Coarser than ~5 cm/px starts to smooth the pile surface and lose toe definition, which shows up directly as volume error. Accuracy also depends on ground control and overlap, not GSD alone.
No. Below ~1 cm/px the limiting factors become ground control quality, image overlap, surface texture, and processing, not pixel size. Flying lower than you need mostly costs battery and coverage. For the full picture of how drone accuracy compares to phone scanning and fixed LiDAR, see our stockpile measurement methods guide.
Rebulk turns drone captures, phone scans, and fixed sensors into one inventory system, so every measurement lands on the same record, whatever captured it.
