2016 USGS QL2 Lidar: Buffalo, Portage, Taylor, and Washburn Counties, WI

This metadata covers four of the six counties covered in the 2016 Wisconsin Statewide Lidar project - Buffalo, Portage, Taylor, and Washburn. Area coverages were approximately 717, 830, 992, and 860 square miles respectively, which includes a 100 meter buffer around each county boundary. The lidar data was acquired at a nominal point spacing (NPS) of 0.7 meters and a single swath nominal point density (NPD) of 2.0. Project specifications are based on Buffalo County requirements and 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 NAD83(2011) / WISCRS appropriate for each county in US survey feet, and vertical datum of NAVD88 - Geoid12A (Feet). Lidar data was acquired using the Orion Optech H300 sensor from March 21st, 2016 to March 22nd, 2016. Acquisition occurred with leaves absent from deciduous trees, when no snow was present on the ground, and with rivers at or below normal levels.

This data, along with its derivatives, is the result of a cooperative partnerships from the counties, Wisconsin DOA, and the USGS 3DEP program. It is part of an effort to obtain statewide lidar coverage in Wisconsin and in the nation.

The following are the USGS lidar fields in JSON:

{

"ldrinfo" : {

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

"ldrsens" : "Optech Orion H300_SN309",

"ldrmaxnr" : "5",

"ldrnps" : "0.69",

"ldranps" : "0.69",

"ldrdens" : "2.19",

"ldradens" : "2.19",

"ldrfltht" : "1700",

"ldrfltsp" : "140",

"ldrscana" : "38",

"ldrscanr" : "52",

"ldrpulsr" : "225",

"ldrpulsd" : "4",

"ldrpulsw" : "0.41",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.25",

"ldrswatw" : "1170.71",

"ldrswato" : "25",

"ldrgeoid" : "National Geodetic Survey (NGS) Geoid12A"

},

"ldraccur" : {

"ldrchacc" : "n/a",

"rawnva" : "0.072",

"rawnvan" : "49"

},

"lasinfo" : {

"lasver" : "1.4",

"lasprf" : "6",

"laswheld" : "n/a",

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

"lasintr" : "11",

"lasclass" : {

"clascode" : "1",

"clasitem" : "Processed, but Unclassified"

},

"lasclass" : {

"clascode" : "2",

"clasitem" : "Bare Earth"

},

"lasclass" : {

"clascode" : "5",

"clasitem" : "High Vegetation"

},

"lasclass" : {

"clascode" : "6",

"clasitem" : "Building"

},

"lasclass" : {

"clascode" : "7",

"clasitem" : "Noise"

},

"lasclass" : {

"clascode" : "9",

"clasitem" : "Water"

},

"lasclass" : {

"clascode" : "10",

"clasitem" : "Ignored Ground"

},

"lasclass" : {

"clascode" : "17",

"clasitem" : "Bridge Decks"

},

"lasclass" : {

"clascode" : "18",

"clasitem" : "High Noise"

}

}}

Distributor assumes no liability for misuse of data.

Any conclusions drawn from the analysis of this information are not the responsibility of NOAA, the Office for Coastal Management or its partners

Buffalo County

Portage County

Taylor County

Washburn County

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.

The project specifications require the vertical accuracy of the lidar data to be calculated and reported according to Non-vegetated Vertical Accuracy (NVA) and Vegetated Vertical Accuracy (VVA) classifications.

The required NVA for this project is 19.6 cm (0.643 survey feet) calculated at the 95 percent confidence level (AccuracyZ). The 95 percent confidence level statistic is derived according to National Standards for Spatial Data Accuracy (NSSDA) methodologies using RMSEz * 1.9600. This requirement is for the vertical accuracy testing of the raw swath lidar data and the derived digital elevation model (DEM). The AccuracyZ statistic is assessed and reported using National Digital Elevation Program (NDEP)/ASPRS Guidelines. The minimum required number of NVA checkpoints for this project area is 45.

The required VVA for this project is 29.4 cm (0.965 survey feet) calculated at the 95th percentile derived according to ASPRS Guidelines, Vertical Accuracy Reporting for Lidar Data, i.e., based on the 95th percentile error in all vegetated land cover classes combined. This requirement is for the vertical accuracy testing of the derived digital elevation model (DEM). The minimum required number of VVA checkpoints for this project area is 35.

The NVA (bare earth and urban area land cover classes) and VVA (tall weeds, forested, and swamp land cover classes) checkpoints were distributed throughout the project area and were surveyed using GPS techniques. See survey report for additional survey methodologies. Elevations from the hydro flattened raster DEM were measured for the x,y location of each check point. Elevations interpolated from the hydro flattened raster DEM surface were then compared to the elevation values of the surveyed control points.

Quantitative value: 0.09 meters, AccuracyZ at 95% confidence level, Test that produced the value:

Buffalo County: Tested 0.072 meters (0.235 survey feet) NVA at the 95 percent confidence level. The NVA of the raw swath was calculated using 49 independent checkpoints located in the Bare Earth and Urban land cover categories.

Portage County: Tested 0.084 meters (0.277 survey feet) NVA at the 95 percent confidence level. The NVA of the raw swath was calculated using 92 independent checkpoints located in the Bare Earth and Urban land cover categories.

Taylor County: Tested 0.084 meters (0.274 survey feet) NVA at the 95 percent confidence level. The NVA of the raw swath was calculated using 58 independent checkpoints located in the Bare Earth and Urban land cover categories.

Washburn County: Tested 0.121 meters (0.398 survey feet) NVA at the 95 percent confidence level. The NVA of the raw swath was calculated using 56 independent checkpoints located in the Bare Earth and Urban land cover categories.

Weighted Average = 0.09 meters at 95 percent confidence level.

Spatial consistency of coverage of the project area was maintained throughout the dataset.

Spatial consistency of coverage of the project area was maintained throughout the dataset.

Data is backed up to cloud storage.