Data Management Plan

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 at submeter resolution to provide nominal 1m spacing of collected points. Two 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:

• 2004-10-01 00:00:00 - Data Collection: Using a LH Systems ALS50 Light Detection and Ranging (LiDAR) system, 41 flight lines of high density (submeter ground sample distance) data were collected over areas in coastal Connecticut (approximately 300 square kilometers). Two returns were recorded for each laser pulse along with an intensity value for each return. The data acquisition occurred in one (1) mission on October 8, 2004. Three (3) airborne global positioning system (GPS) base stations were used to support the LiDAR data acquisition: Moriches 1 continuously operating reference station (CORS) ARP, NGS point P36, and one station Woolpert located using static GPS positioning methods, Madison CP. In addition, twenty-two control points were surveyed through fast-static GPS methods to support the final accuracy analysis and tied into the National Geodetic Survey (NGS) points Moriches CORS and P36.
• 2004-11-01 00:00:00 - Airborne GPS Processing: 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 overlap between flight lines was removed to provide a homogeneous coverage, and the coverage was classified to extract a bare earth digital elevation model (DEM). Airborne GPS is differentially processed using the GrafNAV V4.10 software by Waypoint Consulting of Calgary, Alberta, Canada. The PDOP and distance separation is as follows: P36: Maximum PDOP = 3.58 (maximum) Average Distance Separation: 17 km Madison CP: Maximum PDOP = 3.58 (maximum) Average Distance Separation: 19 km IMU data is processed using the PosPac V4.2 software by Applanix Corporation of Richmond Hill, Ontario, Canada. The reflective surface is derived using the ALS Post Processor software by Leica Geosystems GIS & Mapping Division of Atlanta, Georgia. The classification and quality control (QC) of LiDAR data is carried out using a combination of proprietary software and TerraScan software by Terrasolid Limited of Helsinki, Finland. Two (2) coverages were delivered in the LAS file format: bare-earth and above ground features.
• 2004-11-01 00:00:00 - IMU data Processing: IMU data provides information concerning roll, pitch and yaw of collection platform during collection event. IMU information allows the pulse vector to be properly placed in 3D space allowing the distance from the aircraft reference point to be properly positioned on the elevation model surface. IMU data is processed using the PosPac V4.2 software by Applanix Corporation of Richmond Hill, Ontario, Canada.
• 2004-11-01 00:00:00 - Reflective Surface Generation: The reflective surface is derived using the ALS Post Processor software by Leica Geosystems GIS & Mapping Division of Atlanta, Georgia.
• 2004-12-01 00:00:00 - LIDAR Point Classification The classification and quality control (QC) of LiDAR data is carried out using a combination of proprietary software and TerraScan software by Terrasolid Limited of Helsinki, Finland.
• 2005-01-01 00:00:00 - Output LAS Files Random LIDAR points maintained in UTM coordinate system converted to Geographic projection with units of Decimal Degrees
• 2005-01-01 00:00:00 - Transfer to delivery media: Data is transferred from hard-disk to DVD delivery media using a Primera Bravo DVD/CDROM disc publishing hardware.
• 2006-09-27 00:00:00 - The NOAA Office for Coastal Management (OCM) received files in LAS format. The files contained LiDAR intensity and elevation measurements. OCM performed the following processing on the data to make it available within the LiDAR Data Retrieval Tool (LDART): 1. The las files were converted from State Plane coordinates to Geographic coordinates. 2. The las header fields were sorted by latitude and updated.
• 2008-01-01 00:00:00 - For data management purposes, the Office for Coastal Management (OCM) converted the data from NAVD88 heights to ellipsoid heights using Geoid 03.

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