2012 MDEQ-FEMA Madison-Yazoo Lidar Survey

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.

Atlantic Group will provide LiDAR products to support MDEQ in supporting solutions for a variety of purposes including updating DFIRM maps, hydrologic modeling, transportation routing, floodplain mapping and assessment of natural hazards. Furthermore, the data sets can be utilized by the general public including engineers, surveyors, appraisers and others interested parties to evaluate transportation and land use planning.

10465

A footprint of this data set may be viewed in Google Earth at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/2561/supplemental/ms2012_mdeq_fema_madison_yazoo.KMZ

The MDEQ Tennessee-Tombigbee report may be accessed at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/2561/supplemental/ms2012_mdeq_fema_madison_yazoo.pdf

Any conclusions drawn from the analysis of this information are not the responsibility of the following: MDEQ, USGS, The Atlantic Group, NOAA, the Office for Coastal Management, or its partners.

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

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

;

None

Users should be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its limitations. These data depict the heights at the time of the survey and are only accurate for that time.

To ensure FEMA accuracy of the LiDAR data deliverables, the MGI team will provide MDEQ/Geology a survey plan that calls for the integration of 60 Fundamental Vertical Accuracy checkpoints. Fundamental Vertical Accuracy (FVA) testing will be assessed by using checkpoints in open terrain. FVA is calculated at the 95% confidence level using RMSEz x 1.9600.

see accompanying report at https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/2561/supplemental/ms2012_mdeq_fema_madison_yazoo.pdf; Quantitative Value: 0.49 meters, Test that produced the value: 0.49 m (1.64 ft). Horizontal Accuracy meets the NSSDA RMSE (r) of 2.20 ft and the NSSDA Accuracy (r) of 95% confidence level is 3.80 ft.

see accompanying report at https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/2561/supplemental/ms2012_mdeq_fema_madison_yazoo.pdf; Quantitative Value: 0.11 meters, Test that produced the value: 0.11 m (0.37 ft). Vertical Accuracy meets the NSSDA RMSEz of 0.61 ft and the NSSDA Accuracy (z) of 95% confidence level is 1.19 ft.

Cloud Cover: 0

All data is complete to contracted completeness

Utilizing an Optech 3100 multi-return system, Light Detection and Ranging (LiDAR) data will be collected to support the generation of a high-resolution point-cloud. The system consists of geodetic GPS positioning (AGPS), orientation derived from high-end inertial sensors (IMU), and a high-accuracy laser. The sensor is attached to the aircrafts underside and emits rapid pulses of light that are used to determine distances between the plane and terrain below. LIDAR data will be processed to yield a ground surface (Bare Earth). LAS formatted data will be delivered to MDEQ/Geology classified as bare earth as well as above ground points.