Subject
- Oil storage tanks20
- Vegetation mapping20
- Embankments19
- Fills (Earthwork)19
- Industrial sites19
- Electric lines18
- Hydraulic structures18
- Pipelines18
- Vegetation and climate18
- Ferries17
- Refuse and refuse disposal17
- Waste disposal sites17
- Water treatment plants17
- Automobiles--Collision damage16
- Sewage disposal plants16
- Traffic accident investigation16
- Traffic accidents16
- Traffic safety and wildlife15
- Chimneys14
- Cooling towers14