2017-2018 USGS FEMA Lidar: Red River, TX

Product: These lidar data are processed Classified LAS 1.4 files, formatted to 42187 individual 1500 m x 1500 m tiles and reformatted to Entwine Point Tile format.

Geographic Extent: TX Red River FEMA R6 covering approximately 29528 square miles. Dataset Description: TX Red River FEMA R6 Lidar project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a nominal pulse spacing (NPS) of 0.7 meter. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.2. The data was developed based on a horizontal projection/datum of NAD83 (2011), Universal Transverse Mercator, meters and vertical datum of NAVD88 (GEOID12B), meters. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 42187 individual 1500 m x 1500 m tiles, as tiled Intensity Imagery, and as tiled bare earth DEMs; all tiled to the same 1500 m x 1500 m schema. Ground Conditions: Lidar was collected in late 2017 to spring of 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 531 ground control points that were used to calibrate the lidar to known ground locations established throughout the TX Red River FEMA R6 project area. An additional 1088 independent accuracy checkpoints, 639 in Bare Earth and Urban landcovers (639 NVA points, 449 in Tall Grass and Brushland/Low Trees categories 449 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data.

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 1 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. G16PC00020 CONTRACTOR: Dewberry SUBCONTRACTOR: Airborne Imaging Inc., Leading Edge Geomatics, Ltd., Digital Aerial Solutions, Quantum Spatial and Precision Aerial Reconnaissance acquired and calibrated the Lidar data. 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 v1.2",

"ldrsens" : "Riegl LMS-Q1560",

"ldrmaxnr" : "4",

"ldrnps" : "0.63",

"ldrdens" : "2.5",

"ldranps" : "0.63",

"ldradens" : "2.5",

"ldrfltht" : "2100",

"ldrfltsp" : "160",

"ldrscana" : "60",

"ldrscanr" : "76",

"ldrpulsr" : "800",

"ldrpulsd" : "3",

"ldrpulsw" : "0.9",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.25",

"ldrswatw" : "2353",

"ldrswato" : "30",

"ldrgeoid" : "National Geodetic Survey (NGS) GEOID12B"

},

"ldrinfo" : {

"ldrspec" : "U.S. Geological Survey (USGS) - National Geospatial Program (NGP) Lidar Base Specification v1.2",

"ldrsens" : "Riegl VQ780i",

"ldrmaxnr" : "15",

"ldrnps" : "0.76",

"ldrdens" : "1.746",

"ldranps" : "0.536",

"ldradens" : "3.48",

"ldrfltht" : "1800",

"ldrfltsp" : "100",

"ldrscana" : "60",

"ldrscanr" : "68",

"ldrpulsr" : "280",

"ldrpulsd" : "5",

"ldrpulsw" : "1.5",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.25",

"ldrswatw" : "1996",

"ldrswato" : "55",

"ldrgeoid" : "National Geodetic Survey (NGS) GEOID12B"

},

"ldrinfo" : {

"ldrspec" : "USGS-NGP Base Lidar Specification v1.2",

"ldrsens" : "Riegl Q1560",

"ldrmaxnr" : "15",

"ldrnps" : "0.65",

"ldrdens" : "2.4",

"ldranps" : "0.45",

"ldradens" : "4.8",

"ldrfltht" : "1600",

"ldrfltsp" : "100",

"ldrscana" : "57",

"ldrscanr" : "80",

"ldrpulsr" : "350",

"ldrpulsd" : "5",

"ldrpulsw" : "1.5",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.25",

"ldrswatw" : "1737",

"ldrswato" : "55",

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

},

"ldrinfo" : {

"ldrspec" : "USGS-NGP Base Lidar Specification v1.2",

"ldrsens" : "Leica ALS80 HP",

"ldrmaxnr" : "8",

"ldrnps" : "0.7",

"ldrdens" : "2",

"ldranps" : "0.7",

"ldradens" : "2",

"ldrfltht" : "1701",

"ldrfltsp" : "165",

"ldrscana" : "45.0",

"ldrscanr" : "48.8",

"ldrpulsr" : "314.6",

"ldrpulsd" : "0.03",

"ldrpulsw" : "0.43",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.15",

"ldrswatw" : "1409.38",

"ldrswato" : "11",

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

},

"ldrinfo" : {

"ldrspec" : "USGS-NGP Lidar Base Specification V1.2",

"ldrsens" : "Leica ALS-70 HP, Leica ALS80",

"ldrmaxnr" : "4",

"ldrnps" : "0.62",

"ldrdens" : "2.6",

"ldranps" : "0.62",

"ldradens" : "2.6",

"ldrfltht" : "1850",

"ldrfltsp" : "150",

"ldrscana" : "40",

"ldrscanr" : "53.4",

"ldrpulsr" : "294.6",

"ldrpulsd" : "2.5",

"ldrpulsw" : "0.75",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.22",

"ldrswatw" : "1346",

"ldrswato" : "30",

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

},

"ldrinfo" : {

"ldrspec" : "USGS-NGP Lidar Base Specification V1.2",

"ldrsens" : "Leica ALS-70 HP",

"ldrmaxnr" : "4",

"ldrnps" : "0.64",

"ldrdens" : "2.44",

"ldranps" : "0.64",

"ldradens" : "2.44",

"ldrfltht" : "1900",

"ldrfltsp" : "115",

"ldrscana" : "40",

"ldrscanr" : "46",

"ldrpulsr" : "270",

"ldrpulsd" : "2.5",

"ldrpulsw" : "0.75",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.22",

"ldrswatw" : "1383",

"ldrswato" : "30",

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

},

"ldrinfo" : {

"ldrspec" : "USGS-NGP Lidar Base Specification V1.2",

"ldrsens" : "Leica ALS80",

"ldrmaxnr" : "8",

"ldrnps" : "0.63",

"ldrdens" : "2.54",

"ldranps" : "0.63",

"ldradens" : "2.54",

"ldrfltht" : "1770",

"ldrfltsp" : "155",

"ldrscana" : "45",

"ldrscanr" : "43.3",

"ldrpulsr" : "297",

"ldrpulsd" : "2.93",

"ldrpulsw" : "0.88",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.15-0.25",

"ldrswatw" : "1467.79",

"ldrswato" : "30",

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

},

"ldraccur" : {

"ldrchacc" : "0.998",

"rawnva" : "0.154",

"rawnvan" : "637",

"clsnva" : "0.150",

"clsnvan" : "639",

"clsvva" : "0.207",

"clsvvan" : "449"

},

"lasinfo" : {

"lasver" : "1.4",

"lasprf" : "6",

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

"lasolap" : "Swath "overage" points were identified in these files using the standard LAS overlap bit.",

"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" : "10",

"clasitem" : "Ignored Ground"

},

"lasclass" : {

"clascode" : "17",

"clasitem" : "Bridge Decks"

},

"lasclass" : {

"clascode" : "18",

"clasitem" : "High Noise"

}

}}

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.

Microsoft Windows 7 Enterprise Service Pack 1; ESRI ArcCatalog 10.4

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 at a 95% confidence level, derived according to NSSDA, i.e., based on RMSE of 10 cm in the “bare earth” and "urban" land cover classes. The NVA was tested with 637 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 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: 0.154, Test that produced the value: Tested 0.154 meters 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 637 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 cloud storage.