2007 - 2008 Florida Division of Emergency Management (FDEM) Lidar Project: Blocks 1 - 10 (Southeast Florida and Keys)

This Light Detection and Ranging (LiDAR) LAS dataset is a topographic survey conducted for the State of Florida Division of Emergency

Management LiDAR Project. These data were produced for the Florida Division of Emergency Management. The LiDAR point cloud was flown

at a density sufficient to support a maximum final post spacing of 4 feet for unobscured areas. 3001 Inc. acquired the data from

July 12, 2007 through February 8, 2008. The data was divided into 5000' by 5000' cells that serve as the final tiling scheme. The State

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

The data were collected and are organized into 10 blocks. To determine which block or blocks are in your area of interest,

download ch2mhill_block_index_shapefile.zip at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/520/supplemental/ch2mhill_block_index_shapefile.zip

Each block has a metadata record, a Survey Report, a Vertical Accuracy Report and a LiDAR Processing Report which may be accessed at: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/520/supplemental/

Original contact information:

Contact Org: 3001 Inc

Title: LiDAR Department

Phone: (985) 661 - 3001

Email: lidar@3001inc.com

The State of Florida Division of Emergency Management LiDAR Project Survey data will support the creation of Federal Emergency

Management Agency Flood Insurance Rate Maps (FEMA FIRM) and an integrated ground and surface water model. The State of Florida Division

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

10309

Any conclusions drawn from the analysis of this information are not the responsibility of NOAA, the Office for Coastal Management or its partners.

Unclassified

Unclassified

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 9.2.0.1324

The State of Florida Division of Emergency Management LiDAR survey was collected under the guidance of a Professional Mapper/Surveyor.

The data was collected at a density sufficient to support a maximum final post spacing of 4 feet for unobscured areas.

All ground control processing and adjustment was performed using published coordinate horizontal and vertical datums (e.g. NGS CORS).

For deliverables, Corpscon for Windows Version 5.11.08 (geoid 03) was used for horizontal and vertical datum conversion as well as for

coordinate system conversion purposes (e.g. UTM to State Plane).

The horizontal accuracy baseline spec was for the data to meet or exceed a 3.8 ft horizontal accuracy at the 95% confidence level

using RMSE(r) X 1.7308 as defined by the FGDC Geospatial Positioning Accuracy Standards, Part 3: NSSDA. The horizontal accuracies for

each block were tested. To obtain the tested horizontal accuracy, please refer to the Survey Report for each block, which may be accessed at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/520/supplemental/

To determine which block or blocks are in your area of interest, download ch2mhill_block_index_shapefile.zip at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/520/supplemental/ch2mhill_block_index_shapefile.zip

The accuracy assessment was performed using a standard method to compute the root mean square error (RMSE) based on a comparison

of ground control points (GCP) and filtered LiDAR data points. Filtered LiDAR data has had vegetation and cultural features removed

and by analysis represents bare-earth elevations. The RMSE figure was used to compute the vertical National Standard for Spatial Data

Accuracy (NSSDA). Ground control was established by 3001, Inc. A spatial proximity analysis was used to select edited LiDAR data points

contiguous to the relevant GCPs. A search radius decision rule is applied with consideration of terrain complexity, cumulative error

and adequate sample size. Cumulative error results from the errors inherent in the various sources of horizontal measurement. These

sources include the airborne GPS, GCPs and the uncertainty of the accuracy of the LiDAR data points. This accuracy is achieved prior

to the sub-sampling that occurs through integration with the inertial measurement unit (IMU) positions that are recorded. It is unclear

at this time whether the initial accuracy is maintained. The horizontal accuracy of the GCPs is estimated to be in the range of

approximately 1 to 1.6 inches. Finally, sample size was considered. The specification for the National Standard for Spatial Data

Accuracy is a minimum of 20 points to conduct a statistically significant accuracy evaluation (Minnesota Planning, 1999, Positional

Accuracy Handbook, Minnesota Planning Land Management Information Center, St. Paul, Minnesota., p.3). Most statistical texts indicate

that a minimum of 30 sample points provide a reasonable Approximation of a normal distribution. The intent of the NSSDA is to reflect

the geographic area of interest and the distribution of error in the data set (Federal Geographic Data Committee, 1998, Geospatial National

Standard for Spatial Data Accuracy, Federal Geographic Data Committee Secretariat, Reston, Virginia, p.3-4). Additional steps were taken

to ensure the vertical accuracy of the LiDAR data including:

Step 1: Precision Bore sighting (Check Edge-matching)

Step 2: Compare the LiDAR data to the Field Survey (Field survey is to FEMA specifications and more stringent internal specifications)

Step 3: Automated Filtering

Step 4: Manual Editing (Quality Control)

Step 5: 3-D digitizing and Photogrammetric Compilation of hydrographic breaklines.

The vertical accuracy baseline spec was for the data to meet a fundamental vertical accuracy of 0.60 ft at the 95% confidence level

using RMSE(z) X 1.9600 (as defined by the ASPRS Guidelines: Vertical Accuracy Reporting for Lidar Data"). The vertical accuracies for

each block were tested. To obtain the tested vertical accuracy, please refer to the Survey or Vertical Accuracy Report for each block,

which may be accessed at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/520/supplemental/

To determine which block or blocks are in your area of interest, download ch2mhill_block_index_shapefile.zip at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/520/supplemental/ch2mhill_block_index_shapefile.zip

Cloud Cover: 0

The LAS files were flown at a density sufficient to support a maximum final post spacing of 4 feet for unobscured areas. The bare-earth

surface will contain voids in areas that were densely vegetated, covered by bridges, buildings, water, fresh asphalt, sand, etc.

The Light Detection and Ranging (LiDAR) LAS dataset is a topographic survey conducted for the State of Florida Division of Emergency

Management LiDAR Project. These data were produced for Florida Division of Emergency Management. The LiDAR point cloud was flown at a

density sufficient to support a maximum final post spacing of 4 feet for unobscured areas. 3001 Inc. acquired the data from

July 12, 2007 through February 8, 2008. The data was divided into 5000' by 5000' cells that serve as the final tiling scheme. The State of

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