Data Management Plan

TASK ORDER NAME: EASTERN LONG ISLAND, NEW YORK LIDAR ACQUISITION FOR SANDY RESPONSE

CONTRACT NUMBER: W912P9-10-D-0533

TASK ORDER NUMBER: W81C8X23208588

Woolpert Project Number: 72903

USACE required high-resolution digital elevation data developed from airborne LiDAR technology for the Eastern Long Island, New York. The Area of Interest (AOI) consisted of one hundred sixteen (116) square miles in the

North Atlantic Division.

The final deliverables are listed below. The final LiDAR data was delivered in a UTM projection tiling format, based on a modular layout. The tiles were clipped to eliminate overlap between adjacent tiles.

The 1000 meter x 1000 meter tile file name was derived from the National Grid naming convention.

The data originally was collected with the following specifications: LAS v1.2 classified point cloud NAD83 UTM Zone 18N Meters, NAVD88 GEOID12A Meters.

Original contact information:

Contact Org: US Army Engineers District St. Louis

Phone: 314-331-8389

In addition to these lidar point data, the bare earth Digital Elevation Models (DEM) created from the lidar point data are also available. These data are available for custom download at the link provided in the URL section of this metadata record.

Lineage Statement:
The USACE collected, processed, and provided the data to the NOAA Office for Coastal Management (OCM). OCM received the data and processed it to be available for custom download from the Data Access Viewer (DAV) and for bulk download from https.

Process Steps:

• 2012-11-14 00:00:00 - Using an Optech Gemini LiDAR Sensor, 21 flight lines of high density data, at a nominal pulse spacing (NPS) of 1 meter, were collected along the Eastern Long Island, New York (approximately one hundred sixteen (116) square miles). Data Acquisition Height = 5,500 feet AGL - Aircraft Speed = 125 Knots. Multiple returns were recorded for each laser pulse along with an intensity value for each return. A total of two (2) missions were flown during a period from November 14, 2012 through November 15, 2012. One airborne global positioning system (GPS) base station was used in support of the LiDAR data acquisition. Eighteen (18) ground control points were surveyed through static methods. The geoid used to reduce satellite derived elevations to orthometric heights was Geoid12A. Data for the task order is referenced to the UTM Zone 18N, North American Datum of 1983 (NAD83), and NAVD88, in Meters. Airborne GPS data was differentially processed and integrated with the post processed IMU data to derive a smoothed best estimate of trajectory (SBET). The SBET was used to reduce the LiDAR slant range measurements to a raw reflective surface for each flight line. The coverage was classified to extract a bare earth digital elevation model (DEM) and separate last returns. In addition to the LAS deliverables, one layer of coverage was delivered in the ArcGrid Format: bare-earth.
• 2012-01-01 00:00:00 - The LiDAR system calibration and system performance is verified on a periodic basis using Woolpert's calibration range. The calibration range consists of a large building and runway. The edges of the building and control points along the runway have been located using conventional survey methods. Inertial measurement unit (IMU) misalignment angles and horizontal accuracy are calculated by comparing the position of the building edges between opposing flight lines. The scanner scale factor and vertical accuracy is calculated through comparison of LiDAR data against control points along the runway. Field calibration is performed on all flight lines to refine the IMU misalignment angles. IMU misalignment angles are calculated from the relative displacement of features within the overlap region of adjacent (and opposing) flight lines. The raw LiDAR data is reduced using the refined misalignment angles.
• 2012-11-16 00:00:00 - Once the data acquisition and GPS processing phases are complete, the LiDAR data was processed immediately to verify the coverage had no voids. The GPS and IMU data was post processed using differential and Kalman filter algorithms to derive a best estimate of trajectory. The quality of the solution was verified to be consistent with the accuracy requirements of the project.
• 2012-11-16 00:00:00 - The individual flight lines were inspected to ensure the systematic and residual errors have been identified and removed. Then, the flight lines were compared to adjacent flight lines for any mismatches to obtain a homogenous coverage throughout the project area. The point cloud underwent a classification process to determine bare-earth points and non-ground points utilizing "first and only" as well as "last of many" LiDAR returns. This process determined Default (Class 1), Ground (Class 2),Noise (Class 7), Model Key Points (Class 8), and Overlap (Class 12) classifications. The bare-earth (Class 2 - Ground) LiDAR points underwent a manual QA/QC step to verify that artifacts have been removed from the bare-earth surface. The surveyed ground control points are used to perform the accuracy checks and statistical analysis of the LiDAR dataset.
• 2013-01-01 00:00:00 - The NOAA Office for Coastal Management (OCM) received topographic files in LAS format. The files contained lidar elevation and intensity measurements. The data were received in NAD83 UTM18N, meters Projected Coordinates and were vertically referenced to NAVD88 using the Geoid12a model. The vertical units of the data were meters. OCM performed the following processing for data storage and Digital Coast provisioning purposes: 1. The topographic las files were converted from orthometric (NAVD88) heights to ellipsoidal heights using Geoid12a. 2. The topographic las files were converted from Projected Coordinates (Nad83 UTM18N, meters) to Geographic Coordinates (NAD83, decimal degrees).

This data can be obtained on-line at the following URL:

https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=1436

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