How-to
How to measure landfill volume change from public LiDAR
Public LiDAR programs (PNOA in Spain, USGS 3DEP in the US) fly the same ground more than once. Comparing two epochs over a real polygon gives you a physical, evidence-backed volume change — not an estimate.
3 steps
- Get two real LiDAR epochs over the site — Same polygon, two dates, from a public program — national mapping agencies re-fly known areas on a cycle.
- Calibrate against stable terrain nearby — A ring of ground outside the asset that shouldn't have changed gives you the real systematic offset and noise floor for that specific pair of flights.
- Compute change only above the detection threshold — Per-cell height difference below 3× the calibration noise isn't counted — see the method validated on 4 independent real sites, 2 countries.