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LiDAR Elevation Data: City of Oshkosh, WI 2019

Identification Information

Citation
Title
LiDAR Elevation Data: City of Oshkosh, WI 2019
Originator
U.S. Geological Survey
Publication Date
2020-05-30
Edition
2019
Collection Title
Wisconsin Elevation Data
Other Citation Details
LiDAR capture date: 04/19/2019 Contract No. G16PC00016, Task Order No. 140G0219F0026; CONTRACTOR: Quantum Spatial, Inc.
Abstract
This data represents LiDAR elevation information for the City of Oshkosh, Wisconsin in 2019. The following derivative products are available: classified LAS, hydro breaklines, DEM (city mosaic), tiled DEM, Intensity Images, and a tile index file. [These lidar data are processed Classified LAS 1.4 files, formatted to 151 individual 1500 m x 1500 m tiles; used to create intensity images, 3D breaklines, and hydro-flattened DEMs as necessary Geographic Extent: 1 counties in Wisconsin, covering approximately 131 total square miles. Dataset Description: The Oshkosh 3 Rivers 2018 - City of Oshkosh 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 151 individual 1500 m x 1500 m tiles, as tiled intensity imagery, and as tiled bare earth DEMs; all tiled to the same 1500 m x 1500 m schema. Continuous breaklines were produced in Esri file geodatabase format. Ground Conditions: LiDAR was collected in spring 2019, 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 4 ground control points that were used to calibrate the LiDAR to known ground locations established throughout the project area. An additional 4 independent accuracy checkpoints, 2 in Bare Earth and Urban landcovers (2 NVA points), 2 in Tall Weeds categories (2 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data.
Purpose
This data is intended for reference and mapping purposes, and may be used for basic applications such as viewing, querying, and map output production, or to provide a basemap to support graphical overlays and analysis with other spatial 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 1.0 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.]
Supplemental Information
Data is available for download from: https://web.s3.wisc.edu/wsco-wisconsinview/lidar/Winnebago/Oshkosh_2019_FEMA_Delivery/ Detailed, original metadata accompanying this LiDAR data is available inside the ‘Metadata’ folder: https://web.s3.wisc.edu/wsco-wisconsinview/lidar/Winnebago/Oshkosh_2019_FEMA_Delivery/Metadata/reports/vendor_provided_xml/
Temporal Extent
Time Instant
2019-04-19T00:00:00
Bounding Box
West
-88.693584795
East
-88.4450134707
North
44.1269941327
South
43.9211515622
ISO Topic Category
elevation
Place Keyword
City of Oshkosh
Wisconsin
Place Keyword Thesaurus
GNS
Theme Keyword
Digital elevation models
Theme Keyword Thesaurus
LCSH
Resource Constraints
Use Limitation
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 organization providing these data to the public would be appreciated for products derived from these data.
Status
completed
Maintenance and Update Frequency
unknown
Language
eng
Credit
U.S. Geological Survey
Point of Contact
Contact
U.S. Geological Survey
Point of Contact
Contact
Nick Middleton
Email
nmiddleton@quantumspatial.com
Phone
859-277-8700

Spatial Reference Information

Reference System Identifier
Code
6345
Code Space
EPSG
Version
10.031

Data Quality Information

Completeness Commission
Absolute External Positional Accuracy
Lineage
Process Step
Description
Raw Data and Boresight Processing: The boresight for each lift was done individually as the solution may change slightly from lift to lift. The following steps describe the Raw Data Processing and Boresight process: 1) Technicians processed the raw data to LAS format flight lines using the final GPS/IMU solution. This LAS data set was used as source data for boresight. 2) Technicians first used Quantum Spatial, Inc. proprietary and commercial software to calculate initial boresight adjustment angles based on sample areas selected in the lift. These areas cover calibration flight lines collected in the lift, cross tie, and production flight lines. These areas are well distributed in the lift coverage and cover multiple terrain types that are necessary for boresight angle calculation. The technicians then analyzed the results and made any necessary additional adjustment until it was acceptable for the selected areas. 3) Once the boresight angle calculation was completed for the selected areas, the adjusted settings were applied to all of the flight lines of the lift and checked for consistency. The technicians utilized commercial and proprietary software packages to analyze how well flight line overlaps matched for the entire lift and adjusted as necessary until the results met the project specifications. 4) Once all lifts were completed with individual boresight adjustment, the technicians checked and corrected the vertical misalignment of all flight lines and also the matching between data and ground truth. The relative accuracy was less than or equal to 7 cm RMSEz within individual swaths and less than or equal to 10 cm RMSEz or within swath overlap (between adjacent swaths). 5) The technicians ran a final vertical accuracy check of the boresighted flight lines against the surveyed checkpoints after the z correction to ensure the requirement of NVA = 19.6 cm 95% Confidence Level (Required Accuracy) was met.
Process Step
Description
LAS Point Classification: The point classification was performed as described below. The bare earth surface was manually reviewed to ensure correct classification on the Class 2 (Ground) points. After the bare-earth surface was finalized, it was then used to generate all hydro-breaklines through heads-up digitization. All ground (ASPRS Class 2) LiDAR data inside of the Lake Pond and Double Line Drain hydro-flattened 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 to classify these ground (ASPRS Class 2) points to Ignored ground (ASPRS Class 20). All Lake Pond Island and Double Line Drain Island features were checked to ensure that the ground (ASPRS Class 2) points were reclassified to the correct classification after the automated classification was completed. All overlap data was processed through automated functionality provided by TerraScan to classify the overlapping flight line data to approved classes. The overlap data was classified using standard LAS overlap bit. These classes were created through automated processes only and were not verified for classification accuracy. Due to software limitations within TerraScan, these classes were used to trip the withheld bit within various software packages. These processes were reviewed and accepted through numerous conference calls and pilot study areas. All data were manually reviewed and any remaining artifacts removed using functionality provided by TerraScan and TerraModeler. Global Mapper was used as a final check of the bare earth dataset. GeoCue was then used to create the deliverable industry-standard LAS files for both the All Point Cloud Data and the Bare Earth. Quantum Spatial, Inc. proprietary software was used to perform final statistical analysis of the classes in the LAS files, on a per tile level to verify final classification metrics and full LAS header information.
Process Step
Description
Hydro-Flattened Raster DEM Processing: Class 2 (Ground) LiDAR points in conjunction with the hydro-breaklines were used to create a 1.0 meter hydro-flattened raster DEM. Using automated scripting routines within ArcMap, IMG files were created for each tile. Each surface was reviewed using Global Mapper to check for any surface anomalies or incorrect elevations found within the surface.
Process Step
Description
Intensity Image Generation Processing: GeoCue software was used to create the deliverable intensity images. All overlap classes were ignored during this process. This helps to ensure a more aesthetically pleasing image. The GeoCue software was then used to verify full project coverage as well. GeoTIFF files were then provided as the deliverable for this dataset requirement.
Process Step
Description
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.
Process Step
Description
Add data to UW-Madison archive.
Process Date
2023-06-28T00:00:00

Distribution Information

Format Name
Various
Format Version
1.0
Distributor
University of Wisconsin-Madison
Online Access
https://web.s3.wisc.edu/wsco-wisconsinview/lidar/Winnebago/Oshkosh_2019_FEMA_Delivery/
Protocol
WWW:DOWNLOAD-1.0-http--download
Name
WisconsinView.org
Function
download

Metadata Reference Information

Hierarchy Level
dataset
Metadata File Identifier
42DF286C-77F5-471C-BCAC-6313EC897CE2
Metadata Point of Contact
Name
Arthur H. Robinson Map Library
Position Name
Metadata Technician
Delivery Point
550 N. Park St
City
Madison
Administrative Area
Wisconsin
Postal Code
53706
Country
US
Email
askmap@library.wisc.edu
Phone
(608) 262-1471
Metadata Date Stamp
2023-06-28
Metadata Standard Name
ISO 19139 Geographic Information - Metadata - Implementation Specification
Metadata Standard Version
2007
Character Set
utf8
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