2017 USGS Lidar: Dodge County, WI

Product Description of Original Data:

These lidar data are processed Classified LAS 1.4 files, formatted to 1351 individual 4,500 ft x 4,500 ft tiles; used to create intensity images, 3D breaklines and hydro-flattened DEMs as necessary.

Geographic Extent: The AOI is covering approximately 907 square miles of Dodge County along with a 100-foot buffer zone outside the county for the lidar data.

Dataset Description of Original Data:

The WI Dodge County Lidar 2017 B17 Lidar project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a nominal pulse spacing (NPS) of 0.70 meter. Project specifications were based on the U.S. Geological Survey National Geospatial Program Lidar Base Specification, Version 1.2. The data was developed based on a horizontal projection/datum of NAD 1983 2011 WISCRS Dodge and Jefferson Survey Feet and vertical datum of NAVD88 (GEOID12B), Survey Feet. Lidar data was delivered as; flightline-extent raw LAS v1.4 swaths, classified point cloud LAS v1.4 files formatted to 1351 individual 4,500 ft x 4,500 ft tiles in NAD 1983 2011 WISCRS Dodge and Jefferson Survey Feet. Derivatives were produced as tiled; Bare Earth Surface DEMs, Intensity Images; all tiled to the same 4,500 ft x 4,500 ft schema.

Ground Conditions: Lidar was collected in April of 2017, 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 a total of 15 ground control points that were used to calibrate the lidar to known ground locations established throughout the project area. Additional independent accuracy checkpoints were collected (58 NVA points and 48 VVA points) 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.

The Dodge County Wisconsin QL2 Lidar 2017 project was collected in April 2017. The lidar data will deliver benefits and provide transformational data necessary to gain a better understanding of current topographic conditions within the 907 square mile county.

This high-resolution QL2 lidar dataset addresses several state functional activites including: flood-risk management, infrastructure and construction management, urban and regional planning, natural resources conservation, water supply and quality, cultural resources preservation and management, wildlife habitat management, renewable energy resources, resource mining, agriculture and precision farming, and telecommunications.

USGS Contract No. G16PC00022 CONTRACTOR: Woolpert, Inc.

The following are the USGS lidar fields in JSON:

{

"ldrinfo" : {

"ldrspec" : "USGS NGP Lidar Base Specifications v1.2",

"ldrsens" : "Leica ALS70_HP ",

"ldrmaxnr" : "4",

"ldrnps" : "0.7",

"ldrdens" : "2.0",

"ldranps" : "0.7",

"ldradens" : "2.0",

"ldrfltht" : "1500",

"ldrfltsp" : "150",

"ldrscana" : "50",

"ldrscanr" : "25.8",

"ldrpulsr" : "177.4",

"ldrpulsd" : "9",

"ldrpulsw" : "2.7",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.34",

"ldrswatw" : "1399",

"ldrswato" : "33.36",

"ldrcrs" : "NAD 1983 2011 WISCRS Dodge and Jefferson US Feet",

"ldrgeoid" : "GEOID12B"

},

"ldraccur" : {

"ldrchacc" : "0.273",

"rawnva" : "0.084",

"rawnvan" : "58",

"clsnva" : "0.080",

"clsnvan" : "58",

"clsvva" : "0.248",

"clsvvan" : "48"

},

"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" : "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"

},

"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"

}

}}

The information contained in these data is dynamic and may change over time. The data are not better than the original sources from which they were derived. It is the responsibility of the data user to use the data appropriately and within the limitations of the data for which it was requested and prepared, in general, and these data in particular. The related graphics are intended to aid the data user in acquiring relevant data. It is not appropriate to use the related graphics as data. Woolpert gives no warranty, expressed or implied, as to the accuracy, reliability, or completeness of these data. It is strongly recommended that these data are directly acquired from a Woolpert server, and not indirectly through other sources which may have changed the data in some way. Although these data have been processed successfully upon Woolpert's computer system, no warranty, expressed or implied, is made regarding the utility of the data on another system, or for general or scientific purposes; nor shall the act of distribution constitute any such warranty. This disclaimer applies both to individual use of the data and aggregate use with other data.

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.

LAS data covering the DodgeCo_WI_Lidar_2017 Lidar Task Order was compared to independent survey control points to determine the NVA of the LAS Swath and of the Bare-Earth DEM. In addition, this LAS data was compared to independent VVA points.

LAS Swath Non-Vegetated Vertical Accuracy (NVA) Tested 0.080 Meters Non vegetated vertical accuracy at a 95 percent confidence level, derived according to NSSDA, in open terrain using 0.041 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.

Raw Swath Non-Vegetated Vertical Accuracy (NVA) Tested 0.084 Meters Non vegetated vertical accuracy at a 95 percent confidence level, derived according to NSSDA, in open terrain using (RMSEz) 0.043 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 and tested against the TIN using all lidar points against 58 NVA points.

Bare-Earth DEM Non-Vegetated Vertical Accuracy (NVA) Tested 0.088 Meters Non-Vegetated vertical accuracy at a 95 percent confidence level, derived according to NSSDA, in open terrain using (RMSEz) 0.045 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 and tested against the DEM against 58 NVA points.

Vegetated Vertical Accuracy (VVA) Tested 0.248 Meters at the 95th percentile reported using National Digital Elevation Program (NDEP)/ASPRS Guidelines and tested against the DEM against 48 VVA points. VVA Errors larger than 95th percentile include:

Point 3004, Easting 925031.983, Northing 771142.328, Z-Error 0.259 Meters

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.

The NOAA Office for Coastal Management (OCM) ingested references to the USGS Entwine Point Tiles (EPT) 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.