2020 USGS Lidar: Brown County, WI

Product: These lidar data are processed Classified LAS 1.4 files, formatted to individual 1500 m x 1500 m tiles; used to create intensity images, 3D breaklines, and hydro-flattened DEMs as necessary.

Geographic Extent: Brown County covering approximately 573 total square miles.

Dataset Description: The WI_BrownRusk_2020_B20, Work Unit 227789 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 were developed based on a horizontal projection/datum of NAD 1983 2011 WISCRS Brown Meters, Meter and vertical datum of NAVD88 Geoid 18, Meter. LiDAR data were delivered as processed Classified LAS 1.4 files formatted to 720 individual 1500 m x 1500 m tiles, and as 722 tiled intensity images, and 722 tiled bare earth DEMs; all tiled to the same 1500 m x 1500 m schema. Continuous breaklines were produced in Esri file geodatabase format. Tiles 03581777 and 03581807 are located over water and contain no deliverable points. Because of this, there are 2 fewer LAS deliverables than the 722 that appear in the tile index.

Ground Conditions: LiDAR was collected in spring 2020, 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, NV5 Geospatial utilized a total of 12 ground control points that were used to calibrate the LiDAR to known ground locations established throughout the project area. An additional 61 independent accuracy checkpoints, 33 in Bare Earth and Urban landcovers (33 NVA points), 28 in Tall Weeds categories (28 VVA points), were used to assess the vertical accuracy of the data. These checkpoints 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 DEMs. The purpose of these LiDAR data was to produce high accuracy 3D hydro-flattened digital elevation models (DEMs) with a .5 meter cell size. These raw LiDAR point cloud data were used to create classified LiDAR LAS files, intensity images, 3D breaklines, and hydro-flattened DEMs as necessary.

Contract No. G16PC00016, Task Order No. 140G0220F0108; CONTRACTOR: NV5 Geospatial

The following are the USGS lidar fields in JSON:

{

"ldrinfo" : {

"ldrspec" : "USGS-NGP Base Specification v2.1",

"ldrsens" : "Riegl VQ1560ii",

"ldrmaxnr" : "unlimited",

"ldrnps" : "0.35",

"ldrdens" : "8.0",

"ldranps" : "0.35",

"ldradens" : "8.16",

"ldrfltht" : "1710",

"ldrfltsp" : "140",

"ldrscana" : "29",

"ldrscanr" : "360",

"ldrpulsr" : "2000",

"ldrpulsd" : "3",

"ldrpulsw" : "0.31",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.18",

"ldrswatw" : "1896.0",

"ldrswato" : "20",

"ldrgeoid" : "Geoid 18",

"ldrcrs" : "NAD 1983 2011 WISCRS Brown Meters, Meter"

},

"ldraccur" : {

"ldrchacc" : "0",

"rawnva" : "0",

"rawnvan" : "0"

},

"lasinfo" : {

"lasver" : "1.4",

"lasprf" : "6",

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

"lasolap" : "Any overage point deemed geometrically reliable will be used within the normal classification schema. Overage points are not specifically flagged with any special bit value.",

"lasintr" : "16",

"lasclass" : {

"clascode" : "1",

"clasitem" : "Processed, but Unclassified"

},

"lasclass" : {

"clascode" : "2",

"clasitem" : "Bare-Earth Ground"

},

"lasclass" : {

"clascode" : "6",

"clasitem" : "Buildings"

},

"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 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.

MicroStation Connect; TerraScan Version 21.016; TerraModeler Version 21.008; GeoCue Version 2020.1.22.1; Esri ArcGIS 10.6; Global Mapper 19/20; RiProcess 1.8.6; Windows 10 Operating System

\\point_cloud\tilecls\*.las

This data set was produced to meet ASPRS Positional Accuracy Standards for Digital Geospatial Data (2014) for a 11 (cm) RMSEx / RMSEy Horizontal Accuracy Class which equates to Positional Horizontal Accuracy = +/- 19 cm at a 95% confidence level.

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) = 6.66 cm at 95% Confidence Level or 3.4 cm RMSE

Vegetated Vertical Accuracy (VVA) = 7.77 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 the data pass Non-Vegetated Vertical Accuracy specifications.

Data cover the entire area 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.