NOAA Long Island Sound Topobathymetric Lidar data were collected by NV5 using Leica Chiroptera/Hawkeye 4X and Chiroptera/Hawkeye 5 systems in four blocks. Block01 was flown between 20230305 and 20230411 in 14 missions, block02 was flown between 20230305 and 20230722 in 23 missions, block03 was flown between 20230316 and 20231028 in 13 missions and block04 was flown between 20230410 and 20230530 in 19 missions.

All data in each block includes topobathymetric data in a LAS format 1.4, point data record format 6, with the following classifications in accordance with project specifications and the American Society for Photogrammetry and Remote Sensing (ASPRS) classification standards:

        1   - Unclassified
        1W  - Withheld - edge clip 
        1OW - Overlap Withheld - unrefracted green data from Chiroptera sensor
        2   - Ground
        7W  - Withheld -low noise
        18W - Withheld - high noise
        40  - Bathymetric bottom or submerged topography
        41  - Water surface
        42S - Synthetic- Chiroptera synthetic water surface
        43  - Submerged feature
        45  - Water column
        64  - Submerged Aquatic Vegetation (SAV)
        65 - Overlap bathy bottom - temporally different from a separate lift
        71  - Unclassified associated with areas of overlap bathy bottom/temporal bathymetric differences
        72  - Ground associated with areas of overlap bathy bottom/temporal bathymetric differences
        81  - Water surface associated with areas of overlap bathy bottom/temporal bathymetric differences
        82S - Synthetic - Chiroptera synthetic water surface associated with areas of overlap bathy bottom/temporal bathymetric differences
        85  - Water column associated with areas of overlap bathy bottom/temporal bathymetric differences.

        The channel bits are mapped as the following:
        0 - Chiroptera green shallow laser
        1 - Chiroptera/Hawkeye synthetic water surface
        2 - Hawkeye green deep laser
        3 - Chiroptera NIR

        The user byte is mapped as the following:
        10 - Chiroptera green shallow
        11 - Chiroptera green shallow 4X
        12 - Chiroptera green shallow synthetic
        20 - Hawkeye green deep
        21 - Hawkeye green deep 4X
        22 - Hawkeye green deep synthetic
        30 - Chiroptera NIR

This dataset also includes lidar intensity values, number of returns, return number, time, and scan angle.

After each initial Long Island Sound Topobathymetric Lidar block Delivery submission, NOAA reviewed the data and provided NV5 with a feedback edit review. NV5 has corrected these feedback edits and incorporated them into the final block datasets . Additionally, green laser intensity values were normalized for depth resulting in a full redelivery of all LAS files in block02 and block04. LAS files were compiled in 500 m x 500 m tiles.