Data Management Plan (Deprecated)

This metadata record describes the lidar topographic elevation mapping of Hunterdon County, NJ that occurred in July 2006. Products generated

include lidar point clouds in LAS 1.0 collected with a Leica ALS-50 Aerial Lidar Sensor.

Original contact information:

Contact Name: Angela R. Worley

Contact Org: EarthData International

Title: Project Manager

Phone: 301-948-8550 x222

Email: aworley@earthdata.com

Process Steps:

• 2007-02-26 00:00:00 - EarthData has developed a unique method for processing lidar data to identify and remove elevation points falling on vegetation, buildings, and other non-ground structures. The algorithms for filtering data were utilized within EarthData's proprietary software and commercially available software written by TerraSolid. This software suite of tools provides efficient processing for small to large scale projects and has been incorporated into ISO 9001 compliant production workflows. The following process was employed: - Using the lidar data provided by EarthData, the technician performed calibrations of the data. - Using the lidar data provided by EarthData, the technician performed a visual inspection of the data verify that the flight lines overlap correctly. The technician also verified that there were no voids, and that the data covered the project limits. The technician then selected a series of areas from the data set and inspected them where adjacent flight lines overlapped. These overlapping areas were merged and a process which utilizes ArcGIS 3D Analyst and EarthData's proprietary software was run to detect and color code the differences in elevation values and profiles. The technician reviewed these plots and located the areas that contained systematic errors or distortions that were introduced by the lidar sensor. - Identified systematic distortions were removed and the data were re-inspected. Corrections and adjustments can involve the application of angular deflection or compensation for curvature of the ground surface that can be introduced by crossing from one type of land cover to another. - The lidar data for each flightline was trimmed for the removal of the overlap areas between flightlines. The data was checked against a control network to ensure that vertical requirements were maintained. Conversion to the client-specified datum and projections were then completed. The lidar flightline datasets were then tiled for batch processing and data management. - The initial batch processing removed 95% of points falling on vegetation. The algorithm also removed the points that fell on the edges of hard features such as buildings, elevated roadways and bridges. - The technician interactively processed the data using lidar editing tools. During this final phase, the data was TINed based on desired thematic layers to evaluate the automated classification previously performed. This allowed the technician to quickly reclassify points from one layer to another and recreate the TIN surface to see the effect of edits. Georeferenced images were toggled on and off to aid in identification of problem areas. The data were also examined with an automated profiling tool to aid in reclassification. - The final DEM was written to las 1.0. - The point cloud data delivered in las 1.0
• 2010-09-22 00:00:00 - The NOAA Office for Coastal Management (OCM) received the files in las format. The files contained Lidar elevation and intensity measurements. The data were projected in New Jersey State Plane coordinates, and referenced to NAVD88 using Geoid 03. OCM performed the following processing steps to the data to make it available within the Digital Coast: 1. The data were converted from New Jersey State Plane (NAD83) coordinates to geographic coordinates (NAD83). 2. The data were converted from NAVD88 (orthometric) heights to GRS80 (ellipsoid) heights using Geoid 03. 3. The LAS data were sorted by latitude and the headers were updated.

This data can be obtained on-line at the following URL: https://coast.noaa.gov/dataviewer;