Illegal construction

Illegal construction monitoring identifies new buildings, earthworks, roads, and land-cover conversion in areas where planning, cadastral, zoning, protected-area, or permit overlays define legal status.^[1][2] Satellite change detection detects new buildings, demolished buildings, settlement expansion, and infrastructure change using SAR, optical, or fused observations.^[3][2][1] SAR supports urban change monitoring under cloud and day-night conditions, while optical imagery provides interpretable visual evidence when cloud-free.^[3][1] EO data detects construction-like or land-cover change, and illegality requires non-EO permit, planning, cadastral, zoning, or protected-area data.^[1][2] Vegetation-index mapping can flag vegetation removal before construction in protected or floodplain areas, but vegetation loss alone is not construction or illegality.^[2]