Quantum Spatial, Inc.
20181129
Wisconsin 3 County 2018 QL2 LiDAR; Breaklines
vector data
Product: Breakline data is used to hydroflatten the DEMs created for the Wisconsin
3 County 2018 QL2 LiDAR project. Breaklines are reviewed against LiDAR intensity imagery to
verify completeness of capture. Geographic Extent: 3 counties in Wisconsin, covering
approximately 1622 total square miles. Dataset Description: The Wisconsin 3 County 2018 QL2
LiDAR project called for the planning, acquisition, processing, and derivative products of
lidar data to be collected at a nominal pulse spacing (NPS) of 0.71 meters. Project
specifications are based on the U.S. Geological Survey National Geospatial Program Base
LiDAR Specification, Version 1.3. The data were developed based on a horizontal
projection/datum of NAD 1983 2011 UTM Zone 16N, Meter and vertical datum of NAVD88 GEOID
12B, Meter. LiDAR data were delivered as processed Classified LAS 1.4 files formatted to
4610 individual 1000 m x 1000 m tiles, as tiled intensity imagery, and as tiled bare earth
DEMs; all tiled to the same 1000 m x 1000 m schema. Continuous breaklines were produced in
Esri file geodatabase format. Ground Conditions: LiDAR was collected in spring 2018, 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, Quantum Spatial, Inc. utilized a total of 37 ground control points that were
used to calibrate the LiDAR to known ground locations established throughout the project
area. An additional 125 independent accuracy checkpoints, 69 in Bare Earth and Urban
landcovers (69 NVA points), 56 in Tall Weeds categories (56 VVA points), were used to assess
the vertical accuracy of the data. These checkpoints were not used to calibrate or post
process the data.
To acquire detailed surface elevation data for use in conservation planning, design,
research, floodplain mapping, dam safety assessments and elevation modeling, etc. Classified
LAS files are used to show the manually reviewed bare earth surface. This allows the user to
create intensity images, breaklines and raster DEMs. The purpose of these LiDAR data was to
produce high accuracy 3D hydro-flattened digital elevation models (DEMs) with a 1 meter cell
size. These raw LiDAR point cloud data were used to create classified LiDAR LAS files,
intensity images, 3D breaklines, and hydro-flattened DEMs as necessary.
Breakline File Type = GDB; Breakline Elevation Units = Meter; Downhill Treatment
Applied = Monotonic, Proprietary; Type of Hydro Treatment Required =
Hydro-Flattened
20180430
20180516
Ground condition
None planned
-89.6009568072
-86.8040527501
45.4292964698
43.6413918935
290228.536033
515333.666955
5030656.12064
4834581.08695
None
Model
Breaklines
LAS Point Cloud
Intensity Image
Raster
DEM
Building Footprints
Remote Sensing
Elevation Data
Lidar
Hydrology
None
Wisconsin
Door County
Marquette County
Outagamie County
No restrictions apply to these data.
None. However, users should be aware that temporal changes may have occurred since
this dataset was collected and that some parts of these data may no longer represent actual
surface conditions. Users should not use these data for critical applications without a full
awareness of their limitations. Acknowledgement of the U.S. Geological Survey would be
appreciated for products derived from these data.
Data cover the entire area specified for this project.
These raw LAS and LAS data files include all data points collected. No points have
been removed or excluded. The raw point cloud is of good quality and data passes Non-Vegetated
Vertical Accuracy specifications. Datasets contain complete coverage of tiles. A visual
qualitative assessment was performed to ensure data completeness. There are no void areas or
missing data. All files are inspected to ensure that they conform to the specified file naming
conventions, all files load in their correct geographic position, all files conform to the
project specifications for file standard and content.
Hydro-Flattened Breakline Processing: Class 2 (ground) LiDAR points were used to
create a bare earth surface model. The surface model was then used to heads-up digitize 2D
breaklines of inland streams and rivers with a 100-foot nominal width and inland ponds and
lakes of 2 acres or greater surface area. Elevation values were assigned to all Inland
Ponds and Lakes, Inland Pond and Lake Islands, Inland Stream and River Islands, using
TerraModeler functionality. Elevation values were assigned to all inland streams and
rivers using Quantum Spatial, Inc. proprietary software. All Ground (ASPRS Class 2) LiDAR
data inside of the collected inland breaklines were then classified to Water (ASPRS Class
9) using TerraScan macro functionality. A buffer of 1 meter was also used around each
hydro-flattened feature. These points were moved from ground (ASPRS Class 2) to Ignored
Ground (ASPRS Class 20). The breakline files were then translated to Esri file geodatabase
format using Esri conversion tools. Breaklines were reviewed against LiDAR intensity
imagery to verify completeness of capture. All breaklines were then compared to TINs
(triangular irregular networks) created from ground only points prior to water
classification. The horizontal placement of breaklines was compared to terrain features
and the breakline elevations were compared to LiDAR elevations to ensure all breaklines
matched the LiDAR within acceptable tolerances. Some deviation was expected between
breakline and LiDAR elevations due to monotonicity, connectivity, and flattening rules
that were enforced on the breaklines. Once completeness, horizontal placement, and
vertical variance were reviewed, all breaklines were reviewed for topological consistency
and data integrity using a combination of Esri Data Reviewer tools and proprietary
tools.
2018
Vector
Universal Transverse Mercator
16
0.9996
-87
0.0
500000
0.0
coordinate pair
0.01
0.01
Meter
NAD 1983 2011
Geodetic Reference System 80
6378137.0
298.257222101
NAVD88 GEOID 12B
0.01
Meter
Explicit elevation coordinate included with horizontal coordinates
20181127
Quantum Spatial, Inc.
mailing and physical
523 Wellington Way
Lexington
KY
40503
USA
859-277-8700
859-277-8901
Monday through Friday 8:00 AM to 5:00 PM (Eastern Time)
FGDC Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998
None.
None.
None.
Unclassified
NONE
None.
None.