Meeting the international hydrographic organization requirements for bottom feature detection using the Coastal Zone Mapping and Imaging Lidar (CZMIL)

Abstract

Coastal Zone Mapping and Imaging Lidar (CZMIL) airborne mapping system was specifically designed for use in the USACE National Coastal Mapping Program [1]. CZMIL exceeds the feature detection capability of preceding bathymetric lidar systems. CZMIL is routinely used to map the near-shore environment for engineering and/or nautical charting purposes. International Hydrographic Organization (IHO) Order 1a [2] criteria states that in addition to specific positioning requirements, a survey system must be able to detect “cubic features (2 m × 2 m × 2 m) meters in depths up to 40 meters; 10% of the water depth beyond 40 meters”. Environmental conditions that affect CZMIL's object detection performance include depth, surface conditions, optical properties within the water column, bottom reflectance, and object reflectance. Therefore, it is necessary to characterize CZMIL's seafloor feature detection capabilities under various environmental conditions. The simultaneous collection of the water column's optical parameters coincident with CZMIL's overflights of its targets allows for a more nuanced understanding of the advantages and limitations of the survey system and environment as a whole, beyond merely a binary ‘yes’ or ‘no’ claim to Order 1a capability.