2016 NOAA NGS Topobathy Lidar: Puerto Rico

These data were collected by the National Oceanic Atmospheric Administration National Geodetic Survey Remote Sensing Division using a Riegl VQ-880G system. The data were acquired from 20160219- 20160331 in twenty missions. The data includes topobathy data in an LAS 1.2 format file classified as unclassified (1), ground (2), topo noise (7), bathy noise (22), water column (25), bathymetric bottom or submerged topography (26), water surface (27), derived water surface in accordance with project specifications. The project consists of 309.3 square miles along the shores of Puerto Rico. This dataset contains 3463 - 500 m x 500 m lidar tiles.

This lidar data was required by the National Geodetic Survey (NGS), Remote Sensing Division Coastal Mapping Program (CMP) to enable accurate and consistent measurement of the national shoreline. The CMP works to provide a regularly updated and consistent national shoreline to define America's marine territorial limits and manage coastal resources.

Data include all lidar returns. An automated grounding classification algorithm was used to determine bare earth and submerged topography point classification. The automated grounding was followed with manual editing.

Data for the Puerto Rico Topobathy LiDAR project was acquired by NOAA using a Riegl VQ-880G Topobathy LiDAR systems. All delivered LiDAR data is referenced to:

Horizontal Datum-NAD83 (2011) epoch: 2010

Projection-UTM Zone 19

Horizontal Units-meters

Vertical Datum-NAD83 (2011) epoch: 2010 (ellipsoid heights)

Vertical Units-meters

This dataset encompasses 3,463 500m x 500m tiles in Puerto Rico. Green LiDAR data was acquired.

NOAA acquired and calibrated the LiDAR data.

Any conclusions drawn from the analysis of this information are not the responsibility of NOAA, the National Geodetic Survey, the Office for Coastal Management, or its partners.

This data can be obtained on-line at the following URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=8463;

None

Users should be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its limitations.

The horizontal data positions were obtained using post processed KGPS methods. Data used to test the lidar was collected with Static GPS Observations and compared against the published data. The vertical accuracy of the data is better than plus or minus 0.15 m at 1 sigma.

This data set was produced to meet ASPRS Positional Accuracy Standards for Digital Geospatial Data (2014) for a 41 cm RMSEx/RMSEy Horizontal Accuracy Class which equates to Positional Horizontal Accuracy = +/- 1 meter at a 95% confidence level.

The vertical accuracy of the data is plus or minus 0.15 m at 1 sigma.

Only checkpoints photo-identifiable in the intensity imagery can be used to test the horizontal accuracy of the lidar. Photo-identifiable checkpoints in intensity imagery typically include checkpoints located at the ends of paint stripes on concrete or asphalt surfaces or checkpoints located at 90 degree corners of different reflectivity, e.g. a sidewalk corner adjoining a grass surface. The xy coordinates of checkpoints, as defined in the intensity imagery, are compared to surveyed xy coordinates for each photo-identifiable checkpoint. These differences are used to compute the tested horizontal accuracy of the lidar. As not all projects contain photo-identifiable checkpoints, the horizontal accuracy of the lidar cannot always be tested.

Lidar vendors calibrate their lidar systems during installation of the system and then again for every project acquired. Typical calibrations include cross flights that capture features from multiple directions that allow adjustments to be performed so that the captured features are consistent between all swaths and cross flights from all directions. Horizontal positional accuracy is achieved through rigorous processing of airborne GPS and IMU, use of control, and calibration procedures. Accuracy assessment of these lidar data was performed by NOAA while calibrating the missions. Dewberry did not perform independent accuracy testing on this dataset.