2008 Florida Division of Emergency Management Lidar: Middle Suwannee River

LiDAR Survey for the Suwannee River Water Management District (SRWMD), Florida. The LiDAR aerial acquisition was conducted in January of 2008, and the breaklines and contours were subsequently generated by the Program and Data Solutions (PDS) team. The PDS team is under contract 07-HS-34-14-00-22-469 with the Florida Division of Emergency Management (FDEM) and offered LiDAR and derived products to add-on clients, including the SRWMD, at the same volume-discount unit rates per tile as negotiated for the FDEM contract and utilizing the same Baseline Specifications from FDEM.

The LiDAR dataset for the SRWMD was acquired by Terrapoint USA in January of 2008 and processed to a bare-earth digital terrain model (DTM); it was produced to FDEM Baseline Specifications. Detailed breaklines and contours were produced by the PDS team for the 65-tile area to be mapped. Each tile covers an area of 5000 ft by 5000 ft. The map at Appendix A displays the 65 tiles of the SRWMD for which LiDAR DTMs and LiDAR-derived breaklines and contours were produced by the PDS team.

The FDEM Baseline Specifications require a maximum LiDAR post spacing of 4 feet, i.e., an average point density of less than 1 point per square meter. However, the PDS team required a much higher point density of its subcontractors in order to increase the probability of penetrating dense foliage; with nominal post spacing of 0.7 meters per flight line and 50% sidelap between flight lines, the average point density is 4 points per square meter. With higher point density there is a greater probability of penetrating dense vegetation and minimizing areas defined as "low confidence areas."

The purpose of this LiDAR data was to produce high accuracy 3D terrain geospatial products for Suwannee River Area.

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A report for this project is available at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/4891/supplemental/fl2008_fdem_middlesuwannee_m4891_surveyreport.pdf

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

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/4891/supplemental/fl2008_fdem_middlesuwannee_m4891.kmz

LAS 1.2 format (classes 1,2,7,9,12)

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Any conclusions drawn from the analysis of this information are not the responsibility of FDEM, Terrapoint, 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=4891

The data set is dynamically generated based on user-specified parameters.;

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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.

Lidar source compiled to meet 1m horizontal accuracy.; Quantitative Value: 1.0 meters, Test that produced the value: The PDS team does not perform independent horizontal accuracy testing on the LiDAR. LiDAR vendors perform calibrations on the LiDAR sensor and compare data to adjoing flight lines to ensure LiDAR meets the 1 meter horizontal accuracy standard at the 95% confidence level.

The 3D breaklines inherit the accuracy of the Lidar stereopairs it was acquired from.; Quantitative Value: 0.076 meters, Test that produced the value: Based on the vertical accuracy testing conducted by PDS, using NSSDA and FEMA guidelines, vertical accuracy at the 95% confidence level (called Accuracyz) is computed by the formula RMSEz x 1.9600. The dataset for Suwannee River, Florida satisfies the criteria:

Countywide lidar dataset tested 14.9 cm vertical accuracy at 95% confidence level in open terrain, based on open terrain RMSEz (7.62 cm) x 1.9600.

Countywide lidar dataset tested 18.6 cm vertical accuracy at 95% confidence level in all land cover categories combined, based on consolidated RMSEz (9.45 cm) x 1.9600.

A visual qualitative assessment was performed in the source Lidar dataset. Data met project specifications. Additional information on this process located in the Minimum Technical Standard (MTS report) "Final Report OF Specific Purpose LiDAR Survey - LiDAR-Generated Breaklines and Contours" submited to Florida Division of Emergency Management.

Data covers the tile scheme provided for the county.