Data Management Plan (Deprecated)

LIDAR data is remotely sensed high-resolution elevation data collected by an airborne collection platform. Using a

combination of laser rangefinding, GPS positioning and inertial measurement technologies; LIDAR instruments are able to make

highly detailed Digital Elevation Models (DEMs) of the earth's terrain, man-made structures and vegetation. This data was collected

over a 100 meter swath of the Oahu, Hawaii coastline with a Leica ALS-40 Aerial Lidar Sensor. Multiple returns were recorded for each

pulse in addition to an intensity value.

Original contact information:

Contact Org: NOAA Office for Coastal Management

Phone: 843-740-1202

Email: coastal.info@noaa.gov

Process Steps:

• 2005-09-02 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 aboveground structures. The algorithms for filtering data were utilized within EarthData's proprietary software and commercial 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 work flows. The following is a step-by-step breakdown of the process. 1. Using the lidar data set provided by EarthData, the technician performs calibrations on the data set. 2. Using the lidar data set provided by EarthData, the technician performed a visual inspection of the data to 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 3-D 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. 3. Systematic distortions highlighted in step 2 were removed and the data was 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. 4. The lidar data for each flight line was trimmed in batch for the removal of the overlap areas between flight lines. 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 flight line data sets were then segmented into adjoining tiles for batch processing and data management. 5. The initial batch-processing run removed 95% of points falling on vegetation. The algorithm also removed the points that fell on the edge of hard features such as structures, elevated roadways and bridges. 6. The operator interactively processed the data using lidar editing tools. During this final phase the operator generated a TIN based on a desired thematic layer to evaluate the automated classification performed in step 5. This allowed the operator to quickly re-classify points from one layer to another and recreate the TIN surface to see the effects of edits. Geo-referenced images were toggled on or off to aid the operator in identifying problem areas. The data was also examined with an automated profiling tool to aid the operator in the reclassification. 7. The final DEM was written to an ESRI grid format (.flt). 8. The point cloud data were also delivered in LAS format.
• 2005-09-27 00:00:00 - The NOAA Office for Coastal Management (OCM) received LAS files containing the point cloud elevation data from Earth Data, Inc. OCM performed the following processing on the data to make it available within the Lidar Data Retrieval Tool (LDART): 1. Variable length header records were added to the LAS files to identify projection, datum and sort order. 2. The LAS files were sorted by latitude.
• 2008-02-01 00:00:00 - For data management purposes, the Office for Coastal Management converted the data from NAVD88 elevations to ellipsoid elevations using Geoid 99.

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