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2022 City of Philadelphia Lidar: Philadelphia, PA
 (MI_Metadata)
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    hierarchyLevel:  (MD_ScopeCode) dataset
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    contact:  (CI_ResponsibleParty)
        organisationName:  OCM Partners
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            address:  (CI_Address)
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        organisationName:  NOAA Office for Coastal Management
        contactInfo:  (CI_Contact)
            phone:  (CI_Telephone)
                voice:  (843) 740-1202
            address:  (CI_Address)
                deliveryPoint:  2234 South Hobson Ave
                city:  Charleston
                administrativeArea:  SC
                postalCode:  29405-2413
                country: (missing)
                electronicMailAddress:  coastal.info@noaa.gov
            onlineResource:  (CI_OnlineResource)
                linkage: https://coast.noaa.gov
                protocol:  WWW:LINK-1.0-http--link
                name:  NOAA Office for Coastal Management Website
                description:  NOAA Office for Coastal Management Home Page
                function:  (CI_OnLineFunctionCode) information
        role:  (CI_RoleCode) pointOfContact
    dateStamp:
      DateTime:  2023-06-16T18:44:12
    metadataStandardName:  ISO 19115-2 Geographic Information - Metadata Part 2 Extensions for imagery and gridded data
    metadataStandardVersion:  ISO 19115-2:2009(E)
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    referenceSystemInfo:  (MD_ReferenceSystem)
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            authority:  (CI_Citation)
                title:  NAD83(2011)
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                    date:  2008-11-12
                    dateType:  (CI_DateTypeCode) publication
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                    organisationName:  European Petroleum Survey Group
                    contactInfo:  (CI_Contact)
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            code:  urn:ogc:def:crs:EPSG:6318
            version:  6.18.3
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    referenceSystemInfo:  (MD_ReferenceSystem)
        referenceSystemIdentifier:  (RS_Identifier)
            authority:  (CI_Citation)
                title:  North American Vertical Datum of 1988 (NAVD88) (GEOID18) meters
                alternateTitle:  North American Vertical Datum of 1988 (NAVD88) (GEOID18) meters
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                            linkage: https://apps.epsg.org/api/v1/VerticalCoordRefSystem/5703/?api_key=gml
                            name:  North American Vertical Datum of 1988 (NAVD88) (GEOID18) meters
                            description:  Link to Geographic Markup Language (GML) description of reference system.
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                    organisationName:  European Petroleum Survey Group
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                            name:  European Petroleum Survey Group Geodetic Parameter Registry
                            description:  Registry that accesses the EPSG Geodetic Parameter Dataset, which is a structured dataset of Coordinate Reference Systems and Coordinate Transformations.
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                  axis:
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            code:  urn:ogc:def:crs:EPSG::5703
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    spatialRepresentationInfo:
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    identificationInfo:  (MD_DataIdentification)
        citation:  (CI_Citation)
            title:  2022 City of Philadelphia Lidar: Philadelphia, PA
            alternateTitle:  pa2022_phil_m9848_metadata
            date:  (CI_Date)
                date:  2022
                dateType:  (CI_DateTypeCode) creation
            date:  (CI_Date)
                date:  2022
                dateType:  (CI_DateTypeCode) publication
            identifier:  (MD_Identifier)
                authority:  (CI_Citation)
                    title:  NOAA/NMFS/EDM
                    date: (inapplicable)
                code:
                  Anchor:  InPort Catalog ID 70168
            citedResponsibleParty:  (CI_ResponsibleParty)
                organisationName: (inapplicable)
                contactInfo:  (CI_Contact)
                    onlineResource:  (CI_OnlineResource)
                        linkage: https://www.fisheries.noaa.gov/inport/item/70168
                        protocol:  WWW:LINK-1.0-http--link
                        name:  Full Metadata Record
                        description:  View the complete metadata record on InPort for more information about this dataset.
                        function:  (CI_OnLineFunctionCode) information
                role: (inapplicable)
            citedResponsibleParty:  (CI_ResponsibleParty)
                organisationName: (inapplicable)
                contactInfo:  (CI_Contact)
                    onlineResource:  (CI_OnlineResource)
                        linkage: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/entwine/geoid18/9848/ept.json
                        protocol:  WWW:LINK-1.0-http--link
                        name:  Entwine Point Tile (EPT)
                        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.
                        function:  (CI_OnLineFunctionCode) download
                role: (inapplicable)
            citedResponsibleParty:  (CI_ResponsibleParty)
                organisationName: (inapplicable)
                contactInfo:  (CI_Contact)
                    onlineResource:  (CI_OnlineResource)
                        linkage: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=9849/details/9849
                        protocol:  WWW:LINK-1.0-http--link
                        name:  Custom DEM Download
                        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.
                        function:  (CI_OnLineFunctionCode) download
                role: (inapplicable)
            citedResponsibleParty:  (CI_ResponsibleParty)
                organisationName: (inapplicable)
                contactInfo:  (CI_Contact)
                    onlineResource:  (CI_OnlineResource)
                        linkage: https://www.pasda.psu.edu/download/phillyLiDAR/2022/Metadata_and_Reports/Lidar_Report/65221207_Philadelphia_Mapping_Report.pdf
                        protocol:  WWW:LINK-1.0-http--link
                        name:  Merrick Lidar Report
                        description:  Link to the Merrick lidar report.
                        function:  (CI_OnLineFunctionCode) download
                role: (inapplicable)
            citedResponsibleParty:  (CI_ResponsibleParty)
                organisationName: (inapplicable)
                contactInfo:  (CI_Contact)
                    onlineResource:  (CI_OnlineResource)
                        linkage: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9848/breaklines/index.html
                        protocol:  WWW:LINK-1.0-http--link
                        name:  Hydro Breaklines
                        description:  Link to the hydro breaklines.
                        function:  (CI_OnLineFunctionCode) download
                role: (inapplicable)
            citedResponsibleParty:  (CI_ResponsibleParty)
                organisationName: (inapplicable)
                contactInfo:  (CI_Contact)
                    onlineResource:  (CI_OnlineResource)
                        linkage: https://coast.noaa.gov/lidar/viewer/v/noaapotree.html?r=https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/entwine/geoid18/9848/ept.json
                        protocol:  WWW:LINK-1.0-http--link
                        name:  Potree 3D View
                        description:  Link to view the point cloud (using the Entwine Point Tile (EPT) format) in the 3D Potree viewer.
                        function:  (CI_OnLineFunctionCode) download
                role: (inapplicable)
            citedResponsibleParty:  (CI_ResponsibleParty)
                organisationName: (inapplicable)
                contactInfo:  (CI_Contact)
                    onlineResource:  (CI_OnlineResource)
                        linkage: https://coast.noaa.gov/dataviewer/
                        protocol:  WWW:LINK-1.0-http--link
                        name:  NOAA's Office for Coastal Management (OCM) Data Access Viewer (DAV)
                        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.
                        function:  (CI_OnLineFunctionCode) download
                role: (inapplicable)
            presentationForm: (unknown)
        abstract:  This dataset is lidar point cloud data covering the City of Philadelphia, PA. The data were collected for the City of Philadelphia in April 2022. DEMs were generated from the raw data. This lidar point cloud data covers approximately 239 sq miles total. Each LAS file contains LiDAR point information, which has been calibrated, controlled, and classified. At the time of capture ground conditions were leaf-off, snow free, and water was at normal levels. The lidar mapping requirements and deliverables meet Quality Level One (QL1) standards for final deliverables as outlined in the USGS-NGP Lidar Base Specification 2021, Revision A (https://www.usgs.gov/3DEP/lidarspec). QL1 lidar specifications suggest a pulse density of greater than or equal to 8 pulses per square meter Aggregate Nominal Pulse Density (ANPD), and pulse spacing of less than or equal to 35 centimeters Aggregate Nominal Pulse Spacing (ANPS). Additionally, lidar capture over the city center has increased point density of 16 ppsm. This metadata record supports the data entry in the NOAA Digital Coast Data Access Viewer (DAV). The NOAA Office for Coastal Management (OCM) downloaded las point data files from the PASDA (Pennsylvania Spatial Data Access) site. 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. This data set is an LAZ (compressed LAS) format file containing LIDAR point cloud data.
        purpose:  To provide QL1 elevation data to the City of Philadelphia Office of Innovation and Technology.
        credit:  City of Philadelphia Office of Innovation and Technology, Merrick The custom download may be cited as National Oceanic and Atmospheric Administration (NOAA) Digital Coast Data Access Viewer. Charleston, SC: NOAA Office for Coastal Management. Accessed Aug 01, 2023 at https://coast.noaa.gov/dataviewer.
        status:  (MD_ProgressCode) completed
        pointOfContact:  (CI_ResponsibleParty)
            organisationName:  NOAA Office for Coastal Management
            contactInfo:  (CI_Contact)
                phone:  (CI_Telephone)
                    voice:  (843) 740-1202
                address:  (CI_Address)
                    deliveryPoint:  2234 South Hobson Ave
                    city:  Charleston
                    administrativeArea:  SC
                    postalCode:  29405-2413
                    country: (missing)
                    electronicMailAddress:  coastal.info@noaa.gov
                onlineResource:  (CI_OnlineResource)
                    linkage: https://coast.noaa.gov
                    protocol:  WWW:LINK-1.0-http--link
                    name:  NOAA Office for Coastal Management Website
                    description:  NOAA Office for Coastal Management Home Page
                    function:  (CI_OnLineFunctionCode) information
            role:  (CI_RoleCode) pointOfContact
        pointOfContact:  (CI_ResponsibleParty)
            organisationName:  NOAA Office for Coastal Management
            contactInfo:  (CI_Contact)
                phone:  (CI_Telephone)
                    voice:  (843) 740-1202
                address:  (CI_Address)
                    deliveryPoint:  2234 South Hobson Ave
                    city:  Charleston
                    administrativeArea:  SC
                    postalCode:  29405-2413
                    country: (missing)
                    electronicMailAddress:  coastal.info@noaa.gov
                onlineResource:  (CI_OnlineResource)
                    linkage: https://coast.noaa.gov
                    protocol:  WWW:LINK-1.0-http--link
                    name:  NOAA Office for Coastal Management Website
                    description:  NOAA Office for Coastal Management Home Page
                    function:  (CI_OnLineFunctionCode) information
            role:  (CI_RoleCode) custodian
        resourceMaintenance:  (MD_MaintenanceInformation)
            maintenanceAndUpdateFrequency:  (MD_MaintenanceFrequencyCode) notPlanned
        graphicOverview:  (MD_BrowseGraphic)
            fileName: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9848/supplemental/pa2022_phil_m9848.kmz
            fileDescription:  This graphic displays the footprint for this lidar data set.
            fileType:  KML
        descriptiveKeywords:  (MD_Keywords)
            keyword:  EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION
            keyword:  EARTH SCIENCE > OCEANS > COASTAL PROCESSES > COASTAL ELEVATION
            type:  (MD_KeywordTypeCode) theme
            thesaurusName:  (CI_Citation)
                title:  Global Change Master Directory (GCMD) Science Keywords
                date: (missing)
                edition:  12.3
        descriptiveKeywords:  (MD_Keywords)
            keyword:  CONTINENT
            keyword:  CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA
            keyword:  CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA > PENNSYLVANIA
            keyword:  VERTICAL LOCATION > LAND SURFACE
            type:  (MD_KeywordTypeCode) place
            thesaurusName:  (CI_Citation)
                title:  Global Change Master Directory (GCMD) Location Keywords
                date: (missing)
                edition:  12.3
        descriptiveKeywords:  (MD_Keywords)
            keyword:  LIDAR > Light Detection and Ranging
            type:  (MD_KeywordTypeCode) instrument
            thesaurusName:  (CI_Citation)
                title:  Global Change Master Directory (GCMD) Instrument Keywords
                date: (missing)
                edition:  14.9
        descriptiveKeywords:  (MD_Keywords)
            keyword:  Airplane > Airplane
            type:  (MD_KeywordTypeCode) platform
            thesaurusName:  (CI_Citation)
                title:  Global Change Master Directory (GCMD) Platform Keywords
                date: (missing)
                edition:  14.9
        descriptiveKeywords:  (MD_Keywords)
            keyword:  Lidar - partner (no harvest)
            type:  (MD_KeywordTypeCode) project
            thesaurusName:  (CI_Citation)
                title:  InPort
                date: (inapplicable)
        resourceConstraints:  (MD_LegalConstraints)
            useConstraints:  (MD_RestrictionCode) otherRestrictions
            otherConstraints:  Cite As: OCM Partners, [Date of Access]: 2022 City of Philadelphia Lidar: Philadelphia, PA [Data Date Range], https://www.fisheries.noaa.gov/inport/item/70168.
        resourceConstraints:  (MD_Constraints)
            useLimitation:  NOAA provides no warranty, nor accepts any liability occurring from any incomplete, incorrect, or misleading data, or from any incorrect, incomplete, or misleading use of the data. It is the responsibility of the user to determine whether or not the data is suitable for the intended purpose.
        resourceConstraints:  (MD_LegalConstraints)
            accessConstraints:  (MD_RestrictionCode) otherRestrictions
            useConstraints:  (MD_RestrictionCode) otherRestrictions
            otherConstraints:  Access Constraints: None | 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 Liability: The USER shall indemnify, save harmless, and, if requested, defend those parties involved with the development and distribution of this data, their officers, agents, and employees from and against any suits, claims, or actions for injury, death, or property damage arising out of the use of or any defect in the FILES or any accompanying documentation. Those parties involved with the development and distribution excluded any and all implied warranties, including warranties or merchantability and fitness for a particular purpose and makes no warranty or representation, either express or implied, with respect to the FILES or accompanying documentation, including its quality, performance, merchantability, or fitness for a particular purpose. The FILES and documentation are provided "as is" and the USER assumes the entire risk as to its quality and performance. Those parties involved with the development and distribution of this data will not be liable for any direct, indirect, special, incidental, or consequential damages arising out of the use or inability to use the FILES or any accompanying documentation. Any conclusions drawn from the analysis of this information are not the responsibility of NOAA, the Office for Coastal Management or its partners.
        resourceConstraints:  (MD_SecurityConstraints)
            classification:  (MD_ClassificationCode) unclassified
            classificationSystem: (missing)
            handlingDescription: (missing)
        aggregationInfo:  (MD_AggregateInformation)
            aggregateDataSetName:  (CI_Citation)
                title:  2022 City of Philadelphia Lidar DEM: Philadelphia, PA
                date: (unknown)
                identifier:  (MD_Identifier)
                    authority:  (CI_Citation)
                        title:  NOAA/NMFS/EDM
                        date: (inapplicable)
                    code:  70174
            associationType:  (DS_AssociationTypeCode) crossReference
        aggregationInfo:  (MD_AggregateInformation)
            aggregateDataSetName:  (CI_Citation)
                title:  NOAA Data Management Plan (DMP)
                date: (unknown)
                identifier:  (MD_Identifier)
                    authority:  (CI_Citation)
                        title:  NOAA/NMFS/EDM
                        date: (inapplicable)
                    code:  70168
                citedResponsibleParty:  (CI_ResponsibleParty)
                    organisationName: (inapplicable)
                    contactInfo:  (CI_Contact)
                        onlineResource:  (CI_OnlineResource)
                            linkage: https://www.fisheries.noaa.gov/inportserve/waf/noaa/nos/ocmp/dmp/pdf/70168.pdf
                            protocol:  WWW:LINK-1.0-http--link
                            name:  NOAA Data Management Plan (DMP)
                            description:  NOAA Data Management Plan for this record on InPort.
                            function:  (CI_OnLineFunctionCode) information
                    role: (inapplicable)
            associationType:  (DS_AssociationTypeCode) crossReference
        spatialRepresentationType:  (MD_SpatialRepresentationTypeCode) vector
        language:  eng; US
        topicCategory:  (MD_TopicCategoryCode) elevation
        extent:  (EX_Extent)
            geographicElement:  (EX_GeographicBoundingBox)
                westBoundLongitude:  -75.337789
                eastBoundLongitude:  -74.939567
                southBoundLatitude:  39.81252
                northBoundLatitude:  40.158785
            temporalElement:  (EX_TemporalExtent)
                extent:
                  TimeInstant:
                    description:   | Currentness: Ground Condition
                    timePosition:  2022-03-29
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    distributionInfo:  (MD_Distribution)
        distributionFormat:  (MD_Format)
            name:  Zip
            version: (missing)
            fileDecompressionTechnique:  Zip
        distributionFormat:  (MD_Format)
            name:  LAZ
            version: (missing)
        distributor:  (MD_Distributor)
            distributorContact:  (CI_ResponsibleParty)
                organisationName:  NOAA Office for Coastal Management
                contactInfo:  (CI_Contact)
                    phone:  (CI_Telephone)
                        voice:  (843) 740-1202
                    address:  (CI_Address)
                        deliveryPoint:  2234 South Hobson Ave
                        city:  Charleston
                        administrativeArea:  SC
                        postalCode:  29405-2413
                        country: (missing)
                        electronicMailAddress:  coastal.info@noaa.gov
                    onlineResource:  (CI_OnlineResource)
                        linkage: https://coast.noaa.gov
                        protocol:  WWW:LINK-1.0-http--link
                        name:  NOAA Office for Coastal Management Website
                        description:  NOAA Office for Coastal Management Home Page
                        function:  (CI_OnLineFunctionCode) information
                role:  (CI_RoleCode) distributor
        transferOptions:  (MD_DigitalTransferOptions)
            onLine:  (CI_OnlineResource)
                linkage: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=9848/details/9848
                protocol:  WWW:LINK-1.0-http--link
                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.
                function:  (CI_OnLineFunctionCode) download
        transferOptions:  (MD_DigitalTransferOptions)
            onLine:  (CI_OnlineResource)
                linkage: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9848/index.html
                protocol:  WWW:LINK-1.0-http--link
                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.
                function:  (CI_OnLineFunctionCode) download
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    dataQualityInfo:  (DQ_DataQuality)
        scope:  (DQ_Scope)
            level:  (MD_ScopeCode) dataset
        report:  (DQ_AbsoluteExternalPositionalAccuracy)
            nameOfMeasure:  Vertical Positional Accuracy
            evaluationMethodDescription:  After hand-filtering has been completed and quality checked, a Checkpoint Report is generated to validate that the accuracy of the ground surface is within the defined accuracy specifications. Each surveyed ground check point is compared to the lidar surface by interpolating an elevation from a Triangulated Irregular Network (TIN) of the surface. The MARS derived report provides an in-depth statistical report, including an RMSE of the vertical errors; a primary component in most accuracy standards and a statistically valid assessment of the overall accuracy of the ground surface. Based on 51 ground survey checkpoints, this dataset was tested to meet ASPRS Positional Accuracy Standard for Digital Geospatial Data (2014) for a 10.0 cm RMSEz Vertical Accuracy Class. Actual NVA accuracy was found to be RMSEz=3.333 cm, equating to a plus or minus 6.533 cm at the 95% confidence level. Actual VVA accuracy was found to be plus or minus 10.040 cm at the 95th percentile.
            result: (missing)
        lineage:  (LI_Lineage)
            statement:  Data were collected and processed by Merrick for the City of Philadelphia Office of Innovation and Technology and were made available on the PASDA site. The data were downloaded from the PASDA site by the NOAA Office for Coastal Management (OCM) where the data were processed to make it available for custom download from the NOAA Digital Coast Data Access Viewer (DAV) and for bulk download from AWS S3.
            processStep:  (LI_ProcessStep)
                description:  Lidar acquisition was collected using fixed wing aircraft and two Optech Galaxy T2000 lidar sensors staging from a variety of airports around the project area. Up to eight return values are recorded for each pulse which ensures the greatest chance of ground returns in a heavily forested area. Lidar data collection was accomplished on March 29, 2022 (dates listed are in local time NOT UTC). Each mission represents a lift of the aircraft and system from the ground, collects data, and lands again. Multiple lifts within a day are represented by Mission A, B, C, and D.
                dateTime:
                  DateTime:  2022-03-29T00:00:00
            processStep:  (LI_ProcessStep)
                description:  GNSS/IMU Data A five-minute IMU initialization is conducted on the ground, with the aircraft engines running, prior to flight, to establish fine alignment of the IMU. In air IMU calibration maneuvers were performed at the beginning and ending of all mission collections to ensure the best forward and reverse trajectory processing using the highest quality IMU calibration. During the data collection, the operator recorded information on log sheets which includes weather conditions, lidar operation parameters, and flight line statistics. Data is sent back to the main office for preliminary processing to check overall quality of GNSS / IMU data and to ensure sufficient overlap between flight lines. Any problematic data may be reflown immediately as required. The airborne GNSS data was post-processed using Applanix POSPac Mobile Mapping Suite version 8.x. A fixed bias carrier phase solution was computed in both the forward and reverse chronological directions. Whenever practical, lidar acquisition was limited to periods when the PDOP was less than 4.0. PDOP indicates satellite geometry relating to position. Generally, PDOPs of 3.0 or less result in a good quality solution, however PDOPs between 3.0 and 5.0 can still yield good results most of the time. PDOPs over 6.0 are of questionable results and PDOPs of over 7.0 usually result in a poor solution. Usually as the number of satellites increase the PDOP decreases. Other quality control checks used for the GNSS include analyzing the combined separation of the forward and reverse GNSS processing from one CORS station and the results of the combined separation when processed from two different CORS stations. An analysis of the number of satellites, present during the flight and data collection times, is also performed. The GNSS trajectory was combined with the raw IMU data and post-processed using POSPac Mobile Mapping Suite version 8.x. The SBET and refined attitude data are then utilized in the Optech LMS lidar processing software to compute the laser point-positions. The trajectory is combined with the laser range measurements to produce lidar point cloud data. GNSS Controls Virtual Ground GNSS Base Station(s) were used to control the lidar airborne flight lines. Post processed Trimble CenterPoint RTX correction service is a high-accuracy, satellite-delivered global positioning service. This technology provides high accuracy GNSS positioning without the use of traditional reference station based differential RTK infrastructure and delivers very high cm level accuracy. In addition, CORS are at times used to further QC or enhance the airborne GNSS solution. Lidar Calibration Merrick takes great care to ensure all lidar acquisition missions are carried out in a manner conducive to postprocessing an accurate dataset. Proper Airborne GNSS surveying techniques are always followed including pre- and post-mission static initializations. In-air IMU alignments (figure-eights) are performed both before and after on-site collection to ensure proper calibration of the IMU accelerometers and gyros. A minimum of one cross-flight is planned throughout the project area across all flightlines and over roadways where possible. The cross-flight provides a common control surface used to remove any vertical discrepancies in the lidar data between flightlines. The cross-flight is critical to ensure flightline ties across the project area. The areas of overlap between flightlines are used to boresight (calibrate) the lidar point cloud to achieve proper flightline to flightline alignment in all three axes. Each lidar mission flown is accompanied by a hands-on boresight in the office. After boresighting is complete a detailed statistical report is generated to check relative and absolute accuracies before filtering of lidar begins.
                dateTime:
                  DateTime:  2022-01-01T00:00:00
            processStep:  (LI_ProcessStep)
                description:  The lidar filtering process encompasses a series of automated and manual steps to classify the boresighted point cloud data set. Each project represents unique characteristics in terms of cultural features (urbanized vs. rural areas), terrain type and vegetation coverage. These characteristics are thoroughly evaluated at the onset of the project to ensure that the appropriate automated filters are applied and that subsequent manual filtering yields correctly classified data. Data is most often classified by ground and unclassified, but specific project applications can include a wide variety of classifications including but not limited to buildings, vegetation, power lines, etc. A variety of software packages are used for the auto-filtering, manual filtering and QC of the classified data. Merrick used the ASPRS LAS Specification Version 1.4 R15 (ASPRS, 2011, published 09 July 2019), Point Data Record Format 6 for this project and classified the lidar point cloud in accordance with the following classification classes and bitflags. Merrick has developed several customized automated filters that are applied to the lidar data set based on project specifications, terrain, and vegetation characteristics. A filtering macro, which may contain one or more filtering algorithms, is executed to derive LAS files separated into the different classification groups as defined in the ASPRS classification table. The macros are tested in several portions of the project area to verify the appropriateness of the filters. Often, there is a combination of several filter macros that optimize the filtering based on the unique characteristics of the project. Automatic filtering generally yields a ground surface that is 85 - 90% valid, so additional editing (hand-filtering) is required to produce an accurate ground surface. Lidar data is next taken into a graphic environment using MARS to manually re-classify (or hand-filter) noise and other features that may remain in the ground classification after auto filter. A cross-section of the post auto-filtered surface is viewed to assist in the reclassification of non-ground data artifacts. The following is an example of re-classification of the non-ground points (elevated features) that need to be excluded from the true ground surface. Certain features such as berms, hilltops, cliffs and other features may have been aggressively auto-filtered and points will need to be re-classified into the ground classification. Data in the profile view displays non-ground (Unclassified, class 1) in grey and ground in brown/tan (Class 2). At this point, individual lidar points from the original point cloud have now been parsed into separate classifications.
                dateTime:
                  DateTime:  2022-01-01T00:00:00
            processStep:  (LI_ProcessStep)
                description:  After hand-filtering has been completed and quality checked, a Checkpoint Report is generated to validate that the accuracy of the ground surface is within the defined accuracy specifications. Each surveyed ground check point is compared to the lidar surface by interpolating an elevation from a Triangulated Irregular Network (TIN) of the surface. The MARS derived report provides an in-depth statistical report, including an RMSE of the vertical errors; a primary component in most accuracy standards and a statistically valid assessment of the overall accuracy of the ground surface.
                dateTime:
                  DateTime:  2022-01-01T00:00:00
            processStep:  (LI_ProcessStep)
                description:  Hydro - flattening breaklines are captured per the USGS-NGP Lidar Base Specification 2021, Revision A. Final hydro-flattened breaklines features are appropriately turned into polygons (flat elevations) and polylines (decreasing by elevation) and are used to reclassify ground points in water to water (Class 9). The lidar points around the breaklines are reclassified to ignored ground (Class 20) based on the planned collected point density. The next step in the process is the hydro-flattening breakline collection required for the development of the hydro-flattened DEMs. Merrick will capture hydro-flattening breaklines for waterbodies greater than or equal to approximately eight-tenths (~0.8) hectare (e.g., ~100-meter diameter); double-sided streams and rivers that are greater than or equal to 30 meters in (nominal) width, and; any visible islands greater than or equal to approximately four-tenths (~0.4) hectare. Criteria for Non-Tidal Boundary Waters and Tidal Waters are assumed not applicable. No single-line streams or drainages will be collected, nor will any planimetric features that could be utilized as traditional breaklines. All downstream hydro-flattening breaklines require monotonicity (e.g., streams and rivers). Closed polygonal boundaries of water will maintain a fixed (i.e., flat) elevation.
            processStep:  (LI_ProcessStep)
                description:  The NOAA Office for Coastal Management (OCM) downloaded 752 las point data files from this PASDA site: https://www.pasda.psu.edu/download/phillyLiDAR/2022/LAS/Classified_LAS/ The data were in Pennsylvania State Plane South (NAD83 2011), US survey feet coordinates and NAVD88 (Geoid18) elevations in feet. The data were classified as: 1 - Unclassified, 2 - Ground, 7 - Low Noise, 8 - Model Key Point, 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, 8, 9, 17, 18, 20. OCM performed the following processing on the data for Digital Coast storage and provisioning purposes: 1. The las files were converted to laz format using laszip 2. Internal OCM scripts were run to check the number of points by classification and by flight ID and the gps, elevation, and intensity ranges. 3. Internal OCM scripts were run on the las files to: a. Convert from orthometric (NAVD88) elevations to NAD83 (2011) ellipsoid elevations using the Geoid18 model b. Convert the laz files from Pennsylvania State Plane South (NAD83 2011), US survey feet coordinates to geographic coordinates c. Convert the laz files from elevations in feet to meters d. Assign the geokeys, sort the data by gps time and zip the data to database.
                dateTime:
                  DateTime:  2023-06-15T00:00:00
                processor:  (CI_ResponsibleParty)
                    organisationName:  Office for Coastal Management
                    role:  (CI_RoleCode) processor
            source:  (LI_Source)
                sourceCitation:  (CI_Citation)
                    title:  PASDA
                    date: (missing)
                    citedResponsibleParty:  (CI_ResponsibleParty)
                        organisationName:  PASDA
                        contactInfo:  (CI_Contact)
                            onlineResource:  (CI_OnlineResource)
                                linkage: https://www.pasda.psu.edu/download/phillyLiDAR/2022/LAS/Classified_LAS/
                                protocol:  WWW:LINK-1.0-http--link
                                name:  Philadelphia Lidar PASDA Link
                                description:  Source Citation URL
                                function:  (CI_OnLineFunctionCode) information
                        role:  (CI_RoleCode) publisher
            processStep:  (LI_ProcessStep)
                description:   The vertical values in this data set have been converted to reference North American Vertical Datum of 1988 (NAVD88) (GEOID18) meters, using the GEOID18 grids provided by the National Geodetic Survey. Any datum and projection transformations were then done with the Office for Coastal Management 'datum_shift' program. Compression to an LAZ file was done with the LAStools 'laszip' program and can be unzipped with the same free program (laszip.org) Processing notes:
                dateTime:
                  DateTime:  2023-08-01T07:48:40
                processor:  (CI_ResponsibleParty)
                    individualName:  NOAA Office for Coastal Management
                    contactInfo:  (CI_Contact)
                        address:  (CI_Address)
                            electronicMailAddress:  coastal.info@noaa.gov
                    role:  (CI_RoleCode) processor