Data Management Plan

The project entails the acquisition and processing of LiDAR for approximately 1,265 square miles covering areas of Madison and Eastern Yazoo Counties. Collect and deliver high-density elevation point data derived from multiple-return light detection and ranging (LiDAR) measurements for use in supporting topographic analysis, including applications such as flood plain mapping. Hydro enforced breaklines were collected within the identified Special Flood Hazard Area for Madison County, MS including an additional 221sq. miles in the heavily developed areas in Madison County, and 112 sq. miles in a buffered area along the Big Black River in Yazoo County, MS. The data will be delivered as LiDAR Bare Earth within the areas designated in areas of Madison and Eastern Yazoo Counties to aid in visual interpretation of Flood Basin elevations and for addition to the MDEM elevation dataset. Also included in the delivery was LiDAR Intensity data in Tiff format. The intensity values are a measure of the return signal strength. It measures the peak amplitude of return pulses as they are reflected back from the target to the detector of the LiDAR system. These intensity images are a very useful tool to clients and can be used as a substitute for orthophotos. All data will comply with mapping guidelines and specifications as stated in the FEMA Procedure Memorandum No.61.

Process Steps:

• 2012-01-01 00:00:00 - The flight path will be planned as a series of parallel flight lines with cross flight lines for the purposes of quality control. In addition, the flight plan will include flight line distances of 45 kilometers or less and zigzag flight line collection as a result of the inherent IMU drift associated with IMU systems. A digital flight line layout using OPTECH ALTM NAV flight design software for direct integration into the aircraft flight navigation system was created and used.
• LiDAR Sensor Calibration and LiDAR Processing. LIDAR calibrations are performed to determine and eliminate systematic bias that may occur within the hardware of the ALTM system. The systematic bias that are corrected involve scale, roll, and pitch. In addition to the calibration process regarding sensor installation, for every mission, the runway is kinematically surveyed by making three passes. The LiDAR system is flown at right angles over the runway several times and residuals are generated from the processed data.
• Breaklines were captured within the identified SFHA for Madison County, MS, including a buffered 112 sq. mile area along the Big Black River in Yazoo County, MS. The breaklines are significant hydrological features that are appropriate to support the future development of 2-foot contours meeting a 1.19-foot absolute vertical accuracy at the 95% confidence level. Horizontal accuracy is computed using the formula RMSE (z) x 1.7308: 1-inch = 100 feet equivalent (Accuracy = 2.2 feet or 0.67 meters) as defined by the ASPRS Guidelines: Accuracy Reporting for topographic Data. This guideline implements the National Standard for Spatial Data Accuracy (NSSDA) for testing of topographic data.
• Digital Elevation Models (DEMs) are generated in spatial software and have a final cell size of 4 feet. Each DEM is a 32-bit floating point GeoTiff.
• 2013-09-16 00:00:00 - The NOAA Office for Coastal Management (OCM) received topographic files in .laz format from the Mississippi Department of Environmental Quality (MDEQ). The files contained lidar elevation measurements. The data were received in Mississippi State Plane West 2300, NAD83 coordinates and were vertically referenced to NAVD88 using the Geoid09 model. The vertical units of the data were feet. OCM performed the following processing for data storage and Digital Coast provisioning purposes: 1. The topographic laz files were converted from a Projected Coordinate System (Mississippi State Plane West 2300) to a Geographic Coordinate system (NAD 83). 2. The topographic laz files' horizontal units were converted from feet to decimal degrees. 3. The topographic laz files were cleaned of error points above 492 ft and below 114 ft. 4. The topographic laz files' were converted from NAVD88 elevations to NAD83 ellipsoidal elevations using Geoid03 5. Classification 11 was moved to classification 12 due to OCM system requirements (class 11 is reserved for bathymetric points, though these points are overlap points, Class 12).

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

https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=2561

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