Ayres Associates
unknown
WROC 2015 - Burnett Co. Lidar (2015-2016) - DEM
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.
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. LiDAR data was collected to support the generation of 2-foot contours to meet FEMA vertical accuracy standards. 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.
20150411
20150414
ground condition
None planned
-92.896807
-92.024479
46.159125
45.637407
None
elevation
Lidar
Hydrology
DEM
GRID
surface model
surface data
terrain data
bare earth
raster digital data
3.125 foot pixel
None
Wisconsin
Burnett County
Any and all accessibility to data of or pertaining to the 2015 lidar dataset is to be determined by Burnett County.
None. However, temporal changes to the Earth's surface may have occurred since the acquisition of the lidar data and may no longer represent current bare earth surface conditions.
Burnett County
Jason Towne
Land Information Director/County Surveyor/LIO
Mailing and Physical
7410 County Rd K #120
Siren
WI
54872-9067
U.S.A.
715-349-2599
715-349-2102
jtowne@burnettcounty.org
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)
No formal attribute accuracy tests were conducted.
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.
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
Ayres Associates
2015
BurnettCo_Ground_Control_Report_Final
survey
Madison, WI
Ayres Associates
Digital and/or Hardcopy Resources
2015
ground condition
Burnett County Survey Report
This data source was used (along with the airborne GPS/IMU Data) to aid in the georeferencing of the lidar point cloud data.
LiDAR processing utilizes several software packages, including GeoCue and the TerraSolid suite of processing components. The GeoCue software is a database management system for housing the LiDAR dataset (usually multiple gigabytes in size). GeoCue incorporates a thorough checklist of processing steps and quality assurance/quality control (QA/QC) procedures that assist in the LiDAR workflow. The TerraSolid software suite is used to automate the initial classification of the LiDAR point cloud based on a set of predetermined parameters. Lidar technicians refer to ground cover research (natural and cultural features) within the project area and determine algorithms most suitable for the initial automated LiDAR classification. (Some algorithms/filters recognize the ground in forests well, while others have greater capability in urban areas). During this process each point is given an initial classification (e.g., as ground, vegetation, or noise) based on the point's coordinates and the relation to its neighbors. Classifications to be assigned include all those outlined by ASPRS standards. The initial classifications produce a coarse and inexact dataset, but offer an adequate starting point for the subsequent manual classification procedure. During this step, "overlap" points are automatically classified (those originating from neighboring flightlines) using information gathered from the ABGPS and IMU data. Any duplicate points existing from adjacent flightlines are removed during this process. Hydrographic breaklines are collected using LiDARgrammetry to ensure hydroflattened water surfaces. This process involves manipulating the LiDAR data's intensity information to create a metrically sound stereo environment. From this generated "imagery", breaklines are photogrammetrically compiled. Breakline polygons are created to represent open water bodies. The LiDAR points that fall within these areas are classified as "water." Hydro-flattened breaklines were compiled for ponded water that is 2 acres or greater and double lined streams with a minimum width of 20 feet. Streams break at road crossings (culvert locations). The road fills are not be removed from the DEM. Streams are not broken at bridges. When the identification of a feature as a bridge or culvert cannot be made reliably, the feature will be regarded as a culvert. Breaklines representing streams and rivers shall be smooth, continuous, and monotonic, and represent the water surface without any stair steps except for dams and rapids. All hydrographic breaklines include a 1.5 foot buffer, with the Class 2 (bare earth) points being re-classified as Class 10 (ignored ground). TerraSolid is further used for the subsequent manual classification of the LiDAR points allowing technicians to view the point cloud in a number of ways to ensure accuracy and consistency of points and uniformity of point coverage. The TIN was processed to create a GRID or digital elevation model (DEM) with 3.125 foot pixels.
Unknown
NAD 1983 HARN WISCRS Burnett County Feet
45.8987148658333
-92.45777777777781
45.8987148658333
209999.999
195032.104
coordinate pair
0.000000026498603311608807
0.000000026498603311608807
foot_us
D North American 1983 HARN (Geoid 12A)
GRS 1980
6378137.0
298.257222101
Ayres Associates
Mailing and Physical
5201 E Terrace Drive, Suite 200
Madison
Wisconsin
53704
U.S.A.
(608) 443-1200
(608) 299-2184
DerringerA@AyresAssociates.com
Distributor assumes no liability for misuse of data.
Please contact the organization contact for help in acquiring data.
20160713
Ayres Associates
Mailing and Physical
5201 E. Terrace Drive, Suite 200
Madison
Wisconsin
53704
U.S.A.
(608) 443-1200
(608) 299-2184
DerringerA@AyresAssociates.com
FGDC Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998