Data Management Plan (Deprecated)

Product: Calibrated LiDAR version 1.4 .las tiles, classified for subsequent derivatives.

Geographic Extent: New York, Bronx, Kings, Queens, and Richmond Counties in New York plus an additional 100 m buffer.

Dataset Description: In May 2017, Quantum Spatial (QSI) was contracted by Applied Geographics (AppGeo) to collect topographic and topobathymetric Light Detection and Ranging (LiDAR) data for the City of New York (NYC). QSI collected and processed traditional (near infrared wavelength, Leica ALS80 sensor) LiDAR over the topographic AOI, and spliced together NIR and bathymetric LiDAR (green wavelength, Riegl VQ-880-G sensor) for the topobathymetric AOI. LiDAR point data are delivered in 2,500 X 2,500 ft tiles.

Ground Conditions: Topographic LiDAR was collected in May 2017 with approximately 50% leaf-off conditions. Bathymetric data was collected in July 2017 during low tide time windows. Ground control data were used to geospatially correct the LiDAR point cloud and used to perform quality assurance checks on the final products. In addition, Continuously Operating Reference Stations (CORS) from the New York State Spatial Reference Network (NYSNet) were used to geospatially correct the aircraft positional coordinate data and as base stations for GSP collection. All ground survey work to support the topobathymetric LiDAR acquisition was conducted during the NIR LiDAR collection window. Land cover class check points were also collected throughout the study area to evaluate vertical accuracy.

Lineage Statement:
Data were collected and processed by Quantum Spatial, Inc. for the New York City Department of Information Technology and Telecommunications. The data were retrieved from the New York State GIS FTP website [ address: ftp://ftp.gis.ny.gov/elevation/LIDAR/NYC_TopoBathymetric2017/ ] by the NOAA Office for Coastal Management (OCM), where the data were processed to make it available for custom download from the Data Access Viewer (DAV) and bulk download from https

Process Steps:

• 2018-01-01 00:00:00 - The following outlines the processing of the point cloud data: 1. Flightlines and data were reviewed to ensure complete coverage of the study area and positional accuracy of the laser points. 2. Laser point return coordinates were computed using Waypoint Inertial Explorer and Leica Cloudpro software based on independent data from the LiDAR system, IMU, and aircraft. 3. The raw LiDAR file was assembled into flight lines per return with each point having an associated x, y, and z coordinate. 4. Visual inspection of swath to swath laser point consistencies within the study area were used to perform manual refinements of system alignment. 5. Custom algorithms were designed to evaluate points between adjacent flight lines. Automated system alignment was computed based upon randomly selected swath to swath accuracy measurements that consider elevation, slope, and intensities. Specifically, refinement in the combination of system pitch, roll, and yaw offset parameters optimize internal consistency. 6. Noise (e.g., pits and birds) was filtered using post-processing software, based on known elevation ranges and included the removal of any cycle slips. 7. Using TerraScan and Microstation, ground classifications utilized custom settings appropriate to the study area. 8. The corrected and filtered return points were compared to the ground survey points collected to verify the vertical accuracy. (Citation: Lidar Data)
• 2021-06-02 00:00:00 - The NOAA Office for Coastal Management (OCM) retrieved 1,894 lidar point cloud files in laz format from the New York State GIS website. The files contained lidar elevation and intensity measurements. The data were in NAD83 (2011) State Plane New York Long Island (FIPS 3104) in US Feet, and NAVD88 (Geoid12B) elevations in feet. The data were classified as: 1-Unclassified, 2-Ground, 7 - Low Noise, 9 - Water, 10 - Ignored Ground, 17 - Bridge Decks, 25 - Subway stairwells, 40 - Bathymetric Bottom, 41 - Green Near Water Surface, 45 - Water Column. OCM reclassified 25 - Subway Stairwells to 76 to better conform to ASPRS standards, and otherwise processed all classifications of points to the Digital Coast Data Access Viewer (DAV). OCM performed the following processing on the data for Digital Coast storage and provisioning purposes: 1. An internal OCM script was run to check the number of points by classification and by flight ID and the gps and intensity ranges. 2. Internal OCM scripts were run on the laz files to convert from orthometric (NAVD88) elevations to ellipsoid elevations using the Geoid 12B model, to convert from NY State Plane Long Island (NAD83 2011), US feet coordinates to geographic coordinates, to convert vertical elevations from feet to meters, to assign the geokeys, to sort the data by gps time, and zip the data to database and to http.

Data is available online for bulk or custom downloads

Data is backed up to tape and to cloud storage.