2018 USGS/NRCS Lidar: Southeast Florida

Product: These lidar data are processed Classified LAS 1.4 files, formatted to 4,737 individual 1000 m x 1000 m tiles; used to create intensity images, 3D breaklines and hydro-flattened DEMs as necessary.

Geographic Extent: Florida counties of Broward, Collier, Hendry, Miami-Dade, Monroe, and Palm Beach, covering approximately 1,641 square miles.

Dataset Description: Florida Southeast Lidar project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a nominal pulse spacing (NPS) of 0.35 meter. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.3.

Ground Conditions: Lidar was collected on June 2, 2018, November 28, 29, 30, and December 6, 7, 12, and 17, 2018, while no snow was on the ground and rivers were at or below normal levels. In order to post process the lidar data to meet task order specifications and meet ASPRS vertical accuracy guidelines, Dewberry established a total of 20 ground control points that were used to calibrate the lidar to known ground locations established throughout the Broward, Collier, Hendry, Miami-Dade, Monroe, and Palm Beach counties, Florida project area. An additional 125 independent accuracy checkpoints, 69 in Bare Earth and Urban landcovers (69 NVA points), 56 in Tall Grass and Brushland/Low Trees categories (56 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data. The project consists of 4,737 tiles but one DEM was not delivered because it is a water only tile.

To acquire detailed surface elevation data for use in conservation planning, design, research, floodplain mapping, dam safety assessments and elevation modeling, etc. Classified LAS files are used to show the manually reviewed bare earth surface. This allows the user to create Intensity Images, Breaklines and Raster DEM. The purpose of these lidar data was to produce high accuracy 3D hydro-flattened Digital Elevation Model (DEM) with a 0.5 meter cell size. These lidar point cloud data were used to create intensity images, 3D breaklines, and hydro-flattened DEMs as necessary.

USGS Contract No. G16PC0020 Task Order Number. 140G0218F0178 CONTRACTOR: Dewberry, Inc. SUBCONTRACTOR: Airborne Imaging Inc, Lidar data were acquired and calibrated by Airborne Imaging Inc. All follow-on processing was completed by the prime contractor.

The following are the USGS lidar fields in JSON:

{

"ldrinfo" : {

"ldrspec" : "U.S. Geological Survey (USGS) - National Geospatial Program (NGP) Lidar Base Specification v1.3",

"ldrsens" : "Riegl VQ-1560i",

"ldrmaxnr" : "15",

"ldrnps" : "0.35",

"ldrdens" : "8.00",

"ldranps" : "0.35",

"ldradens" : "8.00",

"ldrfltht" : "1300",

"ldrfltsp" : "160",

"ldrscana" : "60",

"ldrscanr" : "375",

"ldrpulsr" : "2000",

"ldrpulsd" : "3",

"ldrpulsw" : "0.9",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.25",

"ldrswatw" : "1500",

"ldrswato" : "30",

"ldrgeoid" : "National Geodetic Survey (NGS) Geoid12B"

},

"ldrinfo" : {

"ldrspec" : "U.S. Geological Survey (USGS) - National Geospatial Program (NGP) Lidar Base Specification v1.3",

"ldrsens" : "Riegl VQ-1560i",

"ldrmaxnr" : "15",

"ldrnps" : "0.35",

"ldrdens" : "8.00",

"ldranps" : "0.35",

"ldradens" : "8.00",

"ldrfltht" : "1300",

"ldrfltsp" : "160",

"ldrscana" : "60",

"ldrscanr" : "375",

"ldrpulsr" : "2000",

"ldrpulsd" : "3",

"ldrpulsw" : "0.9",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.25",

"ldrswatw" : "1500",

"ldrswato" : "30",

"ldrgeoid" : "National Geodetic Survey (NGS) Geoid12B"

},

"ldraccur" : {

"ldrchacc" : "0.5",

"rawnva" : "0.089",

"rawnvan" : "69",

"clsnva" : "0.080",

"clsnvan" : "69",

"clsvva" : "0.213",

"clsvvan" : "56"

},

"lasinfo" : {

"lasver" : "1.3",

"lasprf" : "6",

"laswheld" : "Withheld (ignore) points were identified in these files using the standard LAS Withheld bit.",

"lasolap" : "Overage points were flagged with the overlap bit for points in all classes except class 2. All ground (class 2) points were used in the final DEM generation. ",

"lasintr" : "16",

"lasclass" : {

"clascode" : "1",

"clasitem" : "Processed, but Unclassified"

},

"lasclass" : {

"clascode" : "2",

"clasitem" : "Bare Earth Ground"

},

"lasclass" : {

"clascode" : "7",

"clasitem" : "Low Noise"

},

"lasclass" : {

"clascode" : "9",

"clasitem" : "Water"

},

"lasclass" : {

"clascode" : "17",

"clasitem" : "Bridge Decks"

},

"lasclass" : {

"clascode" : "18",

"clasitem" : "High Noise"

},

"lasclass" : {

"clascode" : "20",

"clasitem" : "Ignored Ground"

}

}}

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

Data is available online for bulk or custom downloads

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.

Riegl RiProcess OR Leica ALS Post Processor OR Optech LMS; GeoCue; Microstation; Terrascan; ArcGIS 10.x; Windows 8; .las X GB

The project specifications require that only Non-Vegetated Vertical Accuracy (NVA) be computed for raw lidar point cloud swath files. The required accuracy (ACCz) is: 19.6 cm (0.64 ft) at a 95% confidence level, derived according to NSSDA, i.e., based on RMSE of 10 cm (0.33 ft) in the “bare earth” and "urban" land cover classes. The NVA was tested with 69 checkpoints located in bare earth and urban (non-vegetated) areas. These check points were not used in the calibration or post processing of the lidar point cloud data. The checkpoints were distributed throughout the project area and were surveyed using GPS techniques. See survey report for additional survey methodologies. Elevations from the unclassified lidar surface were measured for the x,y location of each check point. Elevations interpolated from the lidar surface were then compared to the elevation values of the surveyed control points. AccuracyZ has been tested to meet 19.6 cm (0.64 ft) or better Non-Vegetated Vertical Accuracy at 95% confidence level using RMSE(z) x 1.9600 as defined by the National Standards for Spatial Data Accuracy (NSSDA); assessed and reported using National Digital Elevation Program (NDEP)/ASRPS Guidelines.Quantitative value: 0.089, Test that produced the value: Tested 8.9 cm (0.29 ft) NVA at a 95% confidence level using RMSE(z) x 1.9600 as defined by the National Standards for Spatial Data Accuracy (NSSDA). The NVA of the raw lidar point cloud swath files was calculated against TINs derived from the final calibrated and controlled swath data using 69 independent checkpoints located in Bare Earth and Urban land cover classes.

These LAS data files include all data points collected. No points have been removed or excluded. A visual qualitative assessment was performed to ensure data completeness. No void areas or missing data exist. The raw point cloud is of good quality and data passes Non-Vegetated Vertical Accuracy specifications.

Data covers the entire area specified for this project.

Data is backed up to tape and to cloud storage.