2021 - 2022 USGS Lidar (QL1): Southeast Minnesota Driftless

Product: Processed, classified lidar point cloud data tiles in LAS 1.4 format.

Geographic Extent: This dataset covers approximately 5847 square miles in southeast Minnesota and consists of 3 deliveries or blocks.

MN_SEDriftless_1 (Work Unit 228969) - Approximately 1,741 square miles in southeast Minnesota, including Dakota, Dodge, Freeborn, Mower, Rice, Scott, Steele, and Waseca counties

MN_SEDriftless_2 (Work Unit 222535) - Approximately 2,268 square miles in southeast Minnesota, including Fillmore, Houston, Wabasha, and Winona counties

MN_SEDriftless_3 (Work Unit 228972) - Approximately 1,838 square miles in southeast Minnesota, including Fillmore, Freeborn, and Mower counties

Dataset Description: MN SE Driftless 2021 lidar project called for the planning, acquisition, processing, and production of derivative products of QL1 lidar data to be collected an aggregate nominal pulse spacing (ANPS) of 0.35-meters and 8 points per square meter (ppsm). Project specifications were based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 2022 revision A. The data was developed based on a horizontal reference system of NAD83 (2011) UTM 15 meters (EPSG 6344) and a vertical reference system of NAVD88 (GEOID18) meters. Lidar data was delivered as processed LAZ 1.4 files formatted to individual 1,000 meters x 1,000 meters tiles.

Ground Conditions: Lidar was collected from April 22, 2021, through June 13, 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, Woolpert established ground control points that were used to calibrate the lidar to known ground locations established throughout the entire project area. An additional independent accuracy checkpoints were collected throughout the entire project area and 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.

This project will support the 3DEP mission, the Natural Resources Conservation Service (NRCS) high-resolution elevation enterprise, and many state and local agencies.

USGS Contract No. G16PC00022, Task Order No. 140G0221F0253, Project Name: MN SE Driftless 2021 B21. Contractor: Woolpert.

The following are the USGS lidar fields in JSON:

{

"ldrinfo" : {

"ldrspec" : "USGS NGP Base Specifications v2022 rev A",

"ldrsens" : "Leica Terrain Mapper",

"ldrmaxnr" : "15",

"ldrnps" : "0.35",

"ldrdens" : "8",

"ldranps" : "0.35",

"ldradens" : "8",

"ldrfltht" : "2000",

"ldrfltsp" : "160",

"ldrscana" : "40",

"ldrscanr" : "150",

"ldrpulsr" : "1600",

"ldrpulsd" : "5",

"ldrpulsw" : "2.5",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.25",

"ldrswatw" : "1456",

"ldrswato" : "25",

"ldrgeoid" : "GEOID18"

},

"ldraccur" : {

"ldrchacc" : "0",

"rawnva" : "0",

"rawnvan" : "0",

"clsnva" : "0",

"clsnvan" : "0",

"clsvva" : "0",

"clsvvan" : "0"

},

"lasinfo" : {

"lasver" : "1.4",

"lasprf" : "6",

"laswheld" : "Geometrically unreliable points were identified using a combination of automated and manual techniques and subsequently classified as high or low noise and given the standard Withheld bit.",

"lasolap" : "The overlap bit flag is not to be used for lidar point clouds intended for inclusion in 3DEP data holdings.",

"lasintr" : "16",

"lasclass" : {

"clascode" : "1",

"clasitem" : "Processed but not classified"

},

"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 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. Acknowledgement of the U.S. Geological Survey would be appreciated for products derived from these data. Woolpert prepared the original data as set forth in the Scope of Services, in accordance with reasonable care and due diligence as set forth in this Agreement, however, due to the easily alterable nature of electronic media, files, documents, and other deliverables, Woolpert makes no warranties, either expressed or implied, with respect to the accuracy, completeness, merchantability, or fitness for any particular purpose, including, but not limited to, use of any/all data as described within this metadata file, by any user of this data. Any use will be at the end-user's sole risk.

Microsoft Windows 10 ; ArcMap 10.7; ArcCatalog 10.7; TerraScan ver. 20; TerraModeler ver. 20; LP360.

This data set was produced to meet ASPRS Positional Accuracy Standards for Digital Geospatial Data (2014) for a 0.148 (m) RMSEx / RMSEy Horizontal Accuracy Class which equates to Positional Horizontal Accuracy = +/- 0.363 m at a 95% confidence level.

LAS Swath Non-Vegetated Vertical Accuracy (NVA) produced to meet 0.196 meters Non-vegetated vertical accuracy at a 95 percent confidence level, derived according to NSSDA using 0.100 meters (RMSEz) x 1.96000 as defined by the National Standards for Spatial Data Accuracy (NSSDA); assessed and reported using National Digital Elevation Program (NDEP)/ASPRS Guidelines.

LAS Swath Vegetated Vertical Accuracy (VVA) produced to meet 0.30 meters Vegetated vertical accuracy at the 95th percentile as defined by the National Standards for Spatial Data Accuracy (NSSDA); assessed and reported using National Digital Elevation Program (NDEP)/ASPRS Guidelines.

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) = 3.54 cm RMSE

Vegetated Vertical Accuracy (VVA) = 27.14 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.

Data covers 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.