2021 LaDOTD Lidar: Greater New Orleans, LA

Product: These lidar data are processed Classified LAS 1.4 files, formatted to 7524 individual 1000 m x 1000 m tiles clipped to the DPA; used to create intensity images, 3D breaklines, hydro-flattened DEMs, and first-return DSMs as necessary.

Geographic Extent: Ascension, Assumption, East Baton Rouge, Hancock, Iberia, Iberville, Jefferson, Lafourche, Orleans, Plaquemines, St. Bernard, St. Charles, St. James, St. John the Baptist, St. Martin, St. Mary, St. Tammany, Terrebonne, West Baton Rouge, counties Louisiana, covering approximately 2851 square miles.

Dataset Description: The 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 meters. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 2.1. The data was developed based on a horizontal projection/datum of NAD83 (2011), UTM Zone 15 North, Meters and vertical datum of NAVD88 (GEOID18), Meters. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 7524 individual 1000 m x 1000 m tiles clipped to the DPA, as tiled Intensity Images, as tiled bare-earth DEMs, as tiled first-return DSMs; all tiled to the same 1000 m x 1000 m schema.

Ground Conditions: Lidar was collected in November 2021, 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, Sanborn Map Company, Inc., established a total of 33 ground control points that were used to calibrate the lidar to known ground locations established throughout the project area. An additional 150 independent accuracy check points, 85 in Bare Earth and Urban landcovers (85 NVA points), 65 in Tall Grass and Brushland/Low Trees categories (65 VVA points), were used to assess the vertical accuracy of the data. These check points were not used to calibrate or post process the data.

This metadata record supports the data entry in the NOAA Digital Coast Data Access Viewer (DAV). For this data set, the DAV is leveraging the Entwine Point Tiles (EPT) hosted by USGS on Amazon Web Services.

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 m cell size.

These lidar point cloud data were used to create intensity images, 3D breaklines, hydro-flattened DEMs, and first-return DSMs as necessary.

Sanborn Map Company, Inc.

The following are the USGS lidar fields in JSON:

{

"ldrinfo" : {

"ldrspec" : "U.S. Geological Survey (USGS) - National Geospatial Program (NGP) Lidar Base Specification v2.1",

"ldrsens" : "Leica TerrainMapper",

"ldrmaxnr" : "15",

"ldrnps" : "0.34",

"ldrdens" : "8.9",

"ldranps" : "0.37",

"ldradens" : "7.2",

"ldrfltht" : "2043",

"ldrfltsp" : "160",

"ldrscana" : "40",

"ldrscanr" : "150",

"ldrpulsr" : "1760",

"ldrpulsd" : "4",

"ldrpulsw" : "0.49",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.25",

"ldrswatw" : "1529",

"ldrswato" : "20",

"ldrgeoid" : "National Geodetic Survey (NGS) Geoid18"

},

"ldraccur" : {

"ldrchacc" : "0.5",

"rawnva" : "0",

"rawnvan" : "0",

"clsnva" : "0",

"clsnvan" : "0",

"clsvva" : "0",

"clsvvan" : "0"

},

"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 not 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" : "17",

"clasitem" : "Bridge Decks"

},

"lasclass" : {

"clascode" : "18",

"clasitem" : "High Noise"

},

"lasclass" : {

"clascode" : "20",

"clasitem" : "Ignored Ground"

},

"lasclass" : {

"clascode" : "21",

"clasitem" : "Snow"

},

"lasclass" : {

"clascode" : "22",

"clasitem" : "Temporal Exclusion"

}

}}

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 and 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.

Leica HxMap v2.7.0; GeoCue v2017.1.14.1; Windows 10 Operating System

This data set was produced to meet ASPRS Positional Accuracy Standard for Digital Geospatial Data (2014) for a 10-cm RMSEz Vertical Accuracy Class.

USGS Determined Vertical Accuracy:

Non-Vegetated Vertical Accuracy (NVA) = 7.86 cm RMSE

Vegetated Vertical Accuracy (VVA) = 17.60 cm at 95th Percentile

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 DPA specified for this project.

Data is backed up to tape and to cloud storage.

The NOAA Office for Coastal Management (OCM) ingested references to the USGS Entwine Point Tile (EPT) files hosted on Amazon Web Services (AWS) into the Digital Coast Data Access Viewer (DAV). The DAV accesses the point cloud as it resides on AWS under the usgs-lidar-public-container.