2015 WROC Lidar: Burnett County, WI

The Burnett County, Wisconsin WROC project area covers 910 square miles. Lidar data was acquired with a nominal point spacing (NPS) of 1.0 meters. The data was developed based on a horizontal projection/datum of Wisconsin County Reference System (WISCRS) - Burnett County Coordinates; North American Datum 1983 (2011), survey feet, and vertically geo-referenced to the North American Vertical Datum 1988 (Geoid 12A), survey feet. Data were converted to geographic coordinates with ellipsoid heights in meters.

Lidar data was acquired using the Orion Optech H300 sensor. Collection occurred in April 2015 during leaf-off conditinons, while no snow was on the ground and rivers were at or below normal levels. The lidar data was calibrated using information collected at the time of flight from GPS base stations on the ground and airborne GPS/IMU in the aircraft. The calibrated lidar data was processed to produce a classified point cloud, bare earth DTM, DEM, DSM, contours, breaklines, and intensity images. The Lidar data was delivered according to a 5,000 foot x 5,000 foot tile schematic.

Lidar was acquired to produce an accurate bare earth surface and to generate 2-ft contours to support county land information efforts.

Point Classes are as follows:

1 = Processed, Unclassified

2 = Bare Earth Ground

5 = High Vegetation

6 = Building

7 = Low Points (Noise)

9 = Water

10 = Ignored Ground

11 = Withheld

17 = Bridge Decks

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

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be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions.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.

Environment as of Metadata Creation: Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS 10.3.1 (Build 4959) Service Pack N/A (Build N/A)

A formal accuracy assessment of the horizontal positional information in the data set has not been conducted.

Surveys were conducted at various sites utilizing the base stations established in the static network. These surveys established “ground truth” data at each site on different surface types, including low grass, high grass, low trees, high trees and urban areas. Statistical comparisons were made between ground truth points collected from the ground survey and the elevation at the associated horizontal coordinates represented on the lidar-derived digital terrain model. To qualify as an acceptable accuracy test, the lidar data must be compared with a dataset of higher accuracy - in this instance, ground survey. To develop a comparable dataset of points from the lidar dataset, a utility from proprietary software was used. The ground control survey results were imported into an ESRI PointZ shapefile with each point's information as attributes. The utility then accessed the lidar and generated a triangulated irregular network (TIN), which is a continuous digital terrain surface, using the bare-earth lidar points and the compiled breaklines. The utility probed the TIN surface to determine its elevations at each of the survey point's horizontal locations. The elevation was then appended as a field to the PointZ shapefile; the attributes for each point were exported to a database and then statistical analysis was performed. A comparison of the ground survey versus lidar model values indicates a vertical root mean square error (RMSEz) of 0.437 US Survey Feet. This is within the FEMA specified vertical accuracy tolerance of 0.61 feet. RMSEz - Urban: 0.178 US Survey Feet RMSEz - Low Grass: 0.192 US Survey Feet RMSEz - Tall Grass: 0.662 US Survey Feet RMSEz - Low Trees: 0.556 US Survey Feet RMSEz - Tall Trees: 0.371 US Survey Feet

Spatial consistency of coverage of the WROC 2015 - Burnett Co. Lidar (2015-2016) project area was maintained throughout the dataset.

Spatial consistency of coverage of the WROC 2015 - Burnett Co. Lidar (2015-2016) project area was maintained throughout the dataset.

Data is backed up to cloud storage.