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OCM Partners, 2024: 2020 SEWRPC Lidar: Milwaukee County, WI, https://www.fisheries.noaa.gov/inport/item/70056.

Item Identification

Title: 2020 SEWRPC Lidar: Milwaukee County, WI
Short Name: wi2020_milwaukee_m9842_metadata
Status: Completed
Creation Date: 2020
Publication Date: 2020-10-05
Abstract:

This Southeastern Wisconsin Regional Planning Commission (SEWRPC) high density lidar project encompassed the entirety of Milwaukee County, Wisconsin, which covers approximately 250 square miles and includes a 333 foot buffer around the county boundary. The airborne lidar data was acquired at an aggregate nominal point density (ANPD) of 30 points per square meter. Project specifications are based on SEWRPC requirements. The data was developed and delivered in State Plane Coordinates, Wisconsin South zone, with a horizontal datum of NAD83(2011) and vertical datum of NAVD88 - Geoid12B, with horizontal and vertical units in US Survey Feet. LiDAR data was acquired using a Riegl VQ 1560i sensor, serial number 4040, from April 2, 2020 to April 3, 2020 in three total lifts. Lidar acquisition occurred with leaves absent from deciduous trees, when no snow was present on the ground and with rivers at or below normal levels. The lidar data was calibrated, processed, and delivered in 2020. The data deliverables include classified point cloud, breaklines, and a digital elevation model. The lidar data is not to be used for purposes other than those outlined by SEWRPC for its partners and stakeholders on this project.

This metadata record supports the data entry in the NOAA Digital Coast Data Access Viewer (DAV).

The NOAA Office for Coastal Management (OCM) received las point data files from the Milwaukee County Land Information Office. The data were processed to the NOAA Digital Coast Data Access Viewer (DAV) to make the data available for bulk and custom downloads. In addition to these lidar point data, the bare earth Digital Elevation Models (DEM) created from the lidar point data are also available. These data are available for custom download at the link provided in the URL section of this metadata record.

Purpose:

This data, along with its derivatives, is the result of a countywide elevation mapping with cooperative partnerships from Southeastern Wisconsin Regional Planning Commission (SEWRPC). This data was produced from lidar data collected in April 2020, which was processed and delivered in October 2020.

Supplemental Information:

The following are the USGS lidar fields in JSON:

{

"ldrinfo" : {

"ldrspec" : "National Geospatial Program (NGP) Lidar Base Specification v1.3",

"ldrsens" : "Riegl VQ 1560i_SN4040",

"ldrmaxnr" : "7",

"ldrnps" : "0.337",

"ldrdens" : "30.0",

"ldranps" : "0.337",

"ldradens" : "30.0",

"ldrfltht" : "1000",

"ldrfltsp" : "145",

"ldrscana" : "58.5",

"ldrscanr" : "388",

"ldrpulsr" : "2000",

"ldrpulsd" : "30",

"ldrpulsw" : "1121",

"ldrwavel" : "194",

"ldrmpia" : "1",

"ldrbmdiv" : "1",

"ldrswatw" : "1121",

"ldrswato" : "60",

"ldrgeoid" : "National Geodetic Survey (NGS) Geoid12B"

},

"ldraccur" : {

"ldrchacc" : "Not Calculated",

"rawnva" : "0.078",

"rawnvan" : "11",

"clsnva" : "0.078",

"clsnvan" : "11"

},

"lasinfo" : {

"lasver" : "1.4",

"lasprf" : "6",

"laswheld" : "Withheld (ignore) points were identified in these files using the standard LAS Withheld bit.",

"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 Ground"

},

"lasclass" : {

"clascode" : "3",

"clasitem" : "Low Vegetation (0 to 0.2 ft)"

},

"lasclass" : {

"clascode" : "4",

"clasitem" : "Medium Vegetation (0.2 to 6.99 ft)"

},

"lasclass" : {

"clascode" : "5",

"clasitem" : "High Vegetation (7 ft and above)"

},

"lasclass" : {

"clascode" : "6",

"clasitem" : "Buildings"

},

"lasclass" : {

"clascode" : "7",

"clasitem" : "Low Noise"

},

"lasclass" : {

"clascode" : "8",

"clasitem" : "Model Keypoints (reduced number of bare earth points)"

},

"lasclass" : {

"clascode" : "9",

"clasitem" : "Water"

},

"lasclass" : {

"clascode" : "17",

"clasitem" : "Bridge Deck"

},

"lasclass" : {

"clascode" : "18",

"clasitem" : "High Noise"

},

"lasclass" : {

"clascode" : "20",

"clasitem" : "Ignored Ground"

},

"lasclass" : {

"clascode" : "23",

"clasitem" : "Trees"

}

}}

Keywords

Theme Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Science Keywords
EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION
Global Change Master Directory (GCMD) Science Keywords
EARTH SCIENCE > OCEANS > COASTAL PROCESSES > COASTAL ELEVATION
ISO 19115 Topic Category
elevation

Spatial Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Location Keywords
CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA
Global Change Master Directory (GCMD) Location Keywords
CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA > WISCONSIN
Global Change Master Directory (GCMD) Location Keywords
VERTICAL LOCATION > LAND SURFACE

Instrument Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Instrument Keywords
LIDAR > Light Detection and Ranging

Platform Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Platform Keywords
Airplane > Airplane

Physical Location

Organization: Office for Coastal Management
City: Charleston
State/Province: SC

Data Set Information

Data Set Scope Code: Data Set
Data Set Type: Elevation
Maintenance Frequency: None Planned
Data Presentation Form: Model (digital)
Distribution Liability:

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

Data Set Credit: Ayres Associates, Southeastern Wisconsin Regional Planning Commission (SEWRPC)

Support Roles

Data Steward

CC ID: 1255104
Date Effective From: 2023
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Distributor

CC ID: 1255103
Date Effective From: 2023
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Metadata Contact

CC ID: 1255105
Date Effective From: 2023
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Point of Contact

CC ID: 1255106
Date Effective From: 2023
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Extents

Currentness Reference: Ground Condition

Extent Group 1

Extent Group 1 / Geographic Area 1

CC ID: 1255109
W° Bound: -88.075628
E° Bound: -87.811807
N° Bound: 43.195998
S° Bound: 42.837963

Extent Group 1 / Time Frame 1

CC ID: 1255108
Time Frame Type: Range
Start: 2020-04-02
End: 2020-04-03

Spatial Information

Spatial Representation

Representations Used

Grid: No
Vector: Yes
Text / Table: No
TIN: No
Stereo Model: No
Video: No

Reference Systems

Reference System 1

CC ID: 1255475

Coordinate Reference System

CRS Type: Geographic 2D
EPSG Code: EPSG:6318
EPSG Name: NAD83(2011)
See Full Coordinate Reference System Information

Access Information

Security Class: Unclassified
Data Access Procedure:

Data is available online for bulk and custom downloads.

Data Access Constraints:

None

Data Use Constraints:

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.

Distribution Information

Distribution 1

CC ID: 1255110
Start Date: 2023-06-01
End Date: Present
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=9842/details/9842
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2023 - Present)
File Name: Customized Download
Description:

Create custom data files by choosing data area, product type, map projection, file format, datum, etc. A new metadata will be produced to reflect your request using this record as a base. Change to an orthometric vertical datum is one of the many options.

File Type (Deprecated): Zip
Compression: Zip

Distribution 2

CC ID: 1255111
Start Date: 2023-06-01
End Date: Present
Download URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9842/index.html
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2023 - Present)
File Name: Bulk Download
Description:

Bulk download of data files in LAZ format, geographic coordinates, orthometric heights. Note that the vertical datum (hence elevations) of the files here are different than described in this document. They will be in an orthometric datum.

File Type (Deprecated): LAZ
Distribution Format: LAS/LAZ - LASer
Compression: Zip

URLs

URL 1

CC ID: 1255101
URL: https://coast.noaa.gov/dataviewer/
Name: NOAA's Office for Coastal Management (OCM) Data Access Viewer (DAV)
URL Type:
Online Resource
File Resource Format: HTML
Description:

The Data Access Viewer (DAV) allows a user to search for and download elevation, imagery, and land cover data for the coastal U.S. and its territories. The data, hosted by the NOAA Office for Coastal Management, can be customized and requested for free download through a checkout interface. An email provides a link to the customized data, while the original data set is available through a link within the viewer.

URL 2

CC ID: 1255134
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9842/supplemental/wi2020_milwaukee_m9842.kmz
Name: Browse Graphic
URL Type:
Browse Graphic
File Resource Format: KML
Description:

This graphic displays the footprint for this lidar data set.

URL 3

CC ID: 1255135
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/entwine/geoid18/9842/ept.json
Name: Entwine Point Tile (EPT)
URL Type:
Online Resource
File Resource Format: json
Description:

Entwine Point Tile (EPT) is a simple and flexible octree-based storage format for point cloud data. The data is organized in such a way that the data can be reasonably streamed over the internet, pulling only the points you need. EPT files can be queried to return a subset of the points that give you a representation of the area. As you zoom further in, you are requesting higher and higher densities. A dataset in EPT will contain a lot of files, however, the ept.json file describes all the rest. The EPT file can be used in Potree and QGIS to view the point cloud.

URL 4

CC ID: 1255136
URL: https://coast.noaa.gov/lidar/viewer/v/noaapotree.html?m=9842&g=geoid18
Name: Potree 3D View
URL Type:
Online Resource
Description:

Link to view the point cloud (using the Entwine Point Tile (EPT) format) in the 3D Potree viewer.

URL 5

CC ID: 1255137
URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=9843/details/9843
Name: Custom DEM Download
URL Type:
Online Resource
File Resource Format: Zip
Description:

Link to custom download, from the Data Access Viewer (DAV), the raster Digital Elevation Model (DEM) data that were created from this lidar data set.

URL 6

CC ID: 1255138
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9842/supplemental/SEWRPC_MilwaukeeCountyLidar_508OCM.pdf
Name: Survey Report
URL Type:
Online Resource
File Resource Format: pdf
Description:

Link to the survey report.

URL 7

CC ID: 1255139
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9842/breaklines/index.html
Name: Hydro Breaklines
URL Type:
Online Resource
File Resource Format: Zip
Description:

Link to the hydro breaklines in ESRI gdb and OGC GeoPackage formats.

Technical Environment

Description:

Terrasolid

Data Quality

Vertical Positional Accuracy:

The project specifications require that only Non-Vegetated Vertical Accuracy (NVA) be computed for raw lidar point cloud swath files. The required accuracy (ACCz) is: 9.8 cm at a 95% confidence level, derived according to NSSDA, i.e., based on RMSE of 5 cm in the bare earth and urban land cover classes.

The NVA was tested with 11 checkpoints located in bare earth and urban (non-vegetated) areas. These check points were not used in the calibration or post processing of the lidar point cloud data. The checkpoints were distributed throughout the project area and were surveyed using GPS techniques. See survey report for additional survey methodologies. Elevations from the unclassified lidar surface were measured for the x,y location of each check point. Elevations interpolated from the lidar surface were then compared to the elevation values of the surveyed control points.

AccuracyZ has been tested to meet 9.8 cm or better Non-Vegetated Vertical Accuracy at 95% confidence level using RMSE(z) x 1.9600 as defined by the National Standards for Spatial Data Accuracy (NSSDA); assessed and reported using National Digital Elevation Program (NDEP)/ASRPS Guidelines.

Tested 0.154 feet NVA at a 95% confidence level (or 2.4 cm RMSE) using RMSE(z) x 1.9600 as defined by the National Standards for Spatial Data Accuracy (NSSDA). The NVA of the raw lidar point cloud swath files was calculated against TINs derived from the final calibrated and controlled swath data using 11 independent checkpoints located in Bare Earth and Urban land cover classes.

Completeness Report:

These LAS data files include all data points collected. No points have been removed or excluded. A visual qualitative assessment was performed to ensure data completeness. No void areas or missing data exist. The raw point cloud is complete and data passes Vertical Accuracy specifications.

Conceptual Consistency:

Data covers the entire area specified for this project.

Data Management

Have Resources for Management of these Data Been Identified?: Yes
Approximate Percentage of Budget for these Data Devoted to Data Management: Unknown
Do these Data Comply with the Data Access Directive?: Yes
Actual or Planned Long-Term Data Archive Location: NCEI-CO
How Will the Data Be Protected from Accidental or Malicious Modification or Deletion Prior to Receipt by the Archive?:

Data is backed up to tape and to cloud storage.

Lineage

Lineage Statement:

Data were collected for the Southeastern Wisconsin Regional Planning Commission (SEWRPC) and were provided to the NOAA Office for Coastal Management (OCM) by the Milwaukee County Land Information Office. OCM processed the data to make it available for custom download from the NOAA Digital Coast Data Access Viewer (DAV) and for bulk download from S3 AWS.

Sources

Data Received from the Milwaukee County Land Information Office

CC ID: 1255140
Contact Role Type: Publisher
Contact Type: Organization
Contact Name: Milwaukee County Land Information Office
Citation URL: https://county.milwaukee.gov/EN/Administrative-Services/Land-Information-Office
Citation URL Name: Milwaukee County Land Information Office

Process Steps

Process Step 1

CC ID: 1255096
Description:

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 RIEGL RiPROCESS 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 technician then analyzed the results and made any necessary additional adjustment until it is 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 match 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 2 cm RMSEz within individual swaths and less than or equal to 5 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 check points after the z correction to ensure the requirement of NVA = 9.8 cm 95% Confidence Level (Required Accuracy) was met. Point classification was performed according to USGS Lidar Base Specification 1.3, and breaklines were collected for water features. Bare earth DEMs were exported from the classified point cloud using collected breaklines for hydroflattening.

Process Date/Time: 2020-10-05 00:00:00

Process Step 2

CC ID: 1255097
Description:

Steps followed by Ayres for LAS Point Cloud Classification:

LiDAR data processing for the point cloud deliverable consists of classifying the LiDAR using a combination of automated classification and manual edit/reclassification processes. On most projects the automated classification routines will correctly classify 90-95 percent of the LiDAR points. The remaining 5-10 percent of the bare earth ground class must undergo manual edit and reclassification.

Because the classified points serve as the foundation for the Terrain, DEM and breakline products, it is necessary for the QA/QC supervisor to review the completed point cloud deliverables prior to the production of any additional products.

The following workflow steps are followed for automated LiDAR classification:

1. Lead technicians review the group of LiDAR tiles to determine which automated classification routines will achieve the best results. Factors such as vegetation density, cultural features, and terrain can affect the accuracy of the automated classification. The lead technicians have the ability to edit or tailor specific routines in order to accommodate the factors mentioned above, and achieve the best results and address errors.

2. Distributive processing is used to maximize the available hardware resources and speed up the automated processing as this is a resource-intensive process.

3. Once the results of the automated classification have been reviewed and passed consistent checks, the supervisor then approves the data tiles for manual classification.

The following workflow steps are followed for manual edits of the LiDAR bare earth ground classification:

1. LiDAR technicians review each tile for errors made by the automated routines and correctly address errors any points that are in the wrong classification. By methodically panning through each tile, the technicians view the LiDAR points in profile, with a TIN surface, and as a point cloud.

2. Any ancillary data available, such as Google Earth, is used to identify any features that may not be identifiable as points so that the technician can make the determination to which classification the feature belongs.

The QA/QC processes for the LiDAR processing phase consist of:

1. The lead technician reviews all automated classification results and adjust the macros as necessary to achieve the optimal efficiency. This is an iterative process, and the technician may need to make several adjustments to the macros, depending upon the complexity of the features in the area being processed.

 During the manual editing process, the LiDAR technicians use a system of QA, whereby they check each other’s edits. This results in several benefits to the process:

 There is a greater chance of catching minor blunders

 It increases communication between technicians on technique and appearance

 Solutions to problems are communicated efficiently

 To ensure consistency across the project area, the supervisor reviews the data once the manual editing is complete.

For this phase of a project, the following specifications are checked against:

• Point cloud – all points must be classified according to the USGS classification standard for LAS. The all-return point cloud must be delivered in fully-compliant LAS version 1.4.

• LAS files will use the Spatial Reference Framework according to project specification and all files shall be projected and defined.

• General Point classifications:

 Class 1. Processed, but unclassified

 Class 2. Bare Earth

 Class 7. Noise

 Class 9. Water

 Class 17. Bridge Decks

 Class 18. High Noise

 Class 20. Ignored ground (Breakline proximity)

• Outliers, noise, blunders, duplicates, geometrically unreliable points near the extreme edge of the swath, and other points deemed unusable are to be identified using the "Withheld" flag. This applies primarily to points which are identified during pre-processing or through automated post-processing routines. Subsequently ide

Process Date/Time: 2021-01-14 00:00:00

Process Step 3

CC ID: 1255141
Description:

The NOAA Office for Coastal Management (OCM) received 1204 las point data files from the Milwaukee County Land Information Office.

The data were in Wisconsin South State Plane (NAD83 2011), US Survey Feet coordinates and NAVD88 (Geoid12b) elevations in US Survey Feet. The data were classified as: 1 - Unclassified, 2 - Ground, 7 - Low Noise, 9 - Water, 17 - Bridge Decks, 18 - High Noise, 20 - Ignored Ground. OCM processed all classifications of points to the Digital Coast Data Access Viewer (DAV). Classes available on the DAV are: 1, 2, 7, 9, 17, 18, 20.

OCM performed the following processing on the data for Digital Coast storage and provisioning purposes:

1. Internal OCM scripts were run to check the number of points by classification and by flight ID and the gps, elevation, and intensity ranges.

2. Internal OCM scripts were run on the las files to:

a. Convert from orthometric (NAVD88) elevations to NAD83 (2011) ellipsoid elevations using the Geoid12b model

b. Convert the las files from Wisconsin South State Plane (NAD83 2011), US Survey Feet coordinates to geographic coordinates

c. Convert from elevations in feet to meters.

d. Assign the geokeys, sort the data by gps time and zip the data to database.

Process Date/Time: 2023-06-01 00:00:00
Process Contact: Office for Coastal Management (OCM)

Related Items

Item Type Relationship Type Title
Data Set (DS) Cross Reference 2020 SEWRPC Lidar DEM: Milwaukee County, WI

Catalog Details

Catalog Item ID: 70056
GUID: gov.noaa.nmfs.inport:70056
Metadata Record Created By: Rebecca Mataosky
Metadata Record Created: 2023-06-01 17:20+0000
Metadata Record Last Modified By: SysAdmin InPortAdmin
Metadata Record Last Modified: 2023-10-17 16:12+0000
Metadata Record Published: 2023-06-02
Owner Org: OCMP
Metadata Publication Status: Published Externally
Do Not Publish?: N
Metadata Last Review Date: 2023-06-02
Metadata Review Frequency: 1 Year
Metadata Next Review Date: 2024-06-02