2007 Florida Division of Emergency Management (FDEM) Lidar Project: Coastal Jefferson County

This Light Detection and Ranging (LiDAR) LAS dataset is a topographic survey conducted for a coalition of GIS practitioners,

including the Florida Division of Emergency Management (FDEM), Florida Water Management Districts, Florida Fish and Wildlife

Conservation Commission, Florida Department of Environmental Protection, Army Corps of Engineers Jacksonville District, and

other state and federal agencies. The goal for this project is to use the LiDAR data as new elevation inputs for updated SLOSH

data grids. The ultimate result is the update of the Regional Hurricane Evacuation Studies (RHES) for the state. The State of Florida

Division of Emergency Management LiDAR Survey was collected under the guidance of a Professional Mapper/Surveyor.

Data were collected for 185 square miles in the coastal (southern) part of Jefferson County, Florida from July 18 - 20, 2007. This is a

classified lidar data set. The data are classified: 1 = Unclassified, 2 = Ground (Bare Earth), 7 = Noise and 9 = Water. The FDEM Baseline

Specifications required a maximum post spacing of 4 feet, however, the PDS (Program and Data Solutions) team required a much higher point

density of its subcontractors in order to increase the probability of penetrating dense foliage during the mandated summer acquisition;

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.

Original contact information:

Contact Org: Florida DEM

Phone: 850-413-9907

Email: gis@dca.state.fl.us

The LiDAR topographic mapping survey is to support the Florida Division of Emergency Management (FDEM) development and maintenance

of Regional Hurricane Evacuations Studies (RHES), which include vulnerability assessments, and to assist disaster response

personnel in understanding the threats to Florida's citizens and visitors. Additional intended uses for this survey are growth

management, map modernization/floodplain mapping, natural lands stewardship, and homeland security planning.

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A complete description of this dataset is available in the Minimum Technical Standard (MTS report) "Final Report of Specific Purpose

LiDAR Survey - LiDAR-Generated Breaklines and Contours" submitted to Florida Division of Emergency Management.

This report may be accessed at: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/555/supplemental/Jefferson_County_FL_LiDAR_Survey_Report.pdf

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

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/555/supplemental/FDEM_Lidar_Jefferson_County_South.kmz

Any conclusions drawn from the analysis of this information are not the responsibility of FDEM, the Office for Coastal Management

or its partners.

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

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.

Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.2.5.1450

Lidar source compiled to meet 1 m horizontal accuracy.; Quantitative Value: 1 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 adjoining flight lines to ensure LiDAR meets the 1 meter horizontal accuracy standard at the 95% confidence

level.

The LiDAR is required to meet 0.60 feet (0.18 m) Fundamental Vertical Accuracy (FVA) and 1.19 feet (0.36 m) Consolidated Vertical Accuracy (CVA).; Quantitative Value: 0.15 meters, Test that produced the value:

Based on the vertical accuracy testing conducted by PDS, using NSSDA and FEMA methodology, vertical accuracy at the 95% confidence

level (called Accuracyz) is computed by the formula RMSEz x 1.9600. The dataset for Jefferson County, Florida satisfies the criteria:

Countywide lidar dataset tested 0.48 ft (0.15 m) FVA at 95% confidence level in open terrain, based on open terrain RMSEz (0.24 ft) x 1.9600.

Countywide lidar dataset tested 0.51 ft (0.16 m) CVA at 95% confidence level in all land cover categories combined, based on consolidated

RMSEz (0.26 ft) x 1.9600.

A visual qualitative assessment was performed in the source Lidar dataset. Small intensity anomalies corresponding to false depressions

in the ground data were found in 0.43 sq. miles of the data. While these intensity anomalies and false depressions impacted a

small geographic extent of the data, do not render the data unusable and are within the acceptable percentage of vertical errors allowed by

the project specifications, these anomalies could still visually be seen in the data. To effectively remove the false depressions from

the bare-earth data, ground points representing the false depression were reclassified from class 2 to class 7 and good ground points were

reclassified from class 1 to class 2 when present in overlap data.

Data covers the tile scheme provided for the county.