Seeing Without Digging
Excavation destroys; remote sensing does not. It reads buried sites through soil, canopy, and pasture, turning survey into archaeology's most productive method.
Aerial photography exploits three distinct surface signatures:
| Signature | How it works |
|---|---|
| Cropmarks | Drier soil over walls stunts crops; deeper soil over ditches keeps them green. |
| Soilmarks | Plowing scatters different-colored buried material. |
| Shadow marks | Low evening sun reveals subtle earthworks. |
LiDAR (laser pulses from aircraft) strips vegetation away using ground-returning pulses, revealing missed landscapes like Maya causeways under jungle canopy.
Ground Geophysics
| Method | Reads | Best For |
|---|---|---|
| Magnetometry | Magnetic contrasts | Fast wide coverage of ditches, pits, kilns, hearths |
| Resistivity | Electrical resistance | Stone walls vs damp ditches |
| GPR | Reflected radar, timed | Depth and plan, 3D slices |
Magnetometry is the workhorse: burnt features like kilns and hearths shine because fire re-aligns soil magnetism. GPR is slower, uniquely giving depth by cutting horizontal floor-by-floor slices.
Pitfall: A picture is not an interpretation. Geophysics shows anomalies. A rectangular anomaly might be a Roman building, a sheepfold, or geology. The instrument tells you where to dig; only excavation tells you what it is.