| 2022 AK DGGS Lidar: Twentymile River Watershed, AK | spatialRepresentationInfo|
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| (MI_Metadata) fileIdentifier: gov.noaa.nmfs.inport:74359 language: LanguageCode: eng characterSet: (MD_CharacterSetCode) UTF8 hierarchyLevel: (MD_ScopeCode) dataset hierarchyLevelName: Elevation contact: (CI_ResponsibleParty) organisationName: OCM Partners contactInfo: (CI_Contact) phone: (CI_Telephone) voice: (missing) address: (CI_Address) role: (CI_RoleCode) resourceProvider contact: (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 dateStamp: DateTime: 2025-03-27T20:25:44 metadataStandardName: ISO 19115-2 Geographic Information - Metadata Part 2 Extensions for imagery and gridded data metadataStandardVersion: ISO 19115-2:2009(E) return to top spatialRepresentationInfo: (MD_VectorSpatialRepresentation) topologyLevel: (MD_TopologyLevelCode) geometricObjects: (MD_GeometricObjects) geometricObjectType: (MD_GeometricObjectTypeCode) point geometricObjectCount: 1018623953 return to top referenceSystemInfo: (MD_ReferenceSystem) referenceSystemIdentifier: (RS_Identifier) authority: (CI_Citation) title: NAD83(2011) / UTM zone 6N date: (CI_Date) date: 2008-11-12 dateType: (CI_DateTypeCode) publication citedResponsibleParty: (CI_ResponsibleParty) organisationName: European Petroleum Survey Group contactInfo: (CI_Contact) onlineResource: (CI_OnlineResource) linkage: https://apps.epsg.org/api/v1/CoordRefSystem/6335/export/?format=gml role: (missing) code: urn:ogc:def:crs:EPSG:6335 version: 6.18.3 return to top identificationInfo: (MD_DataIdentification) citation: (CI_Citation) title: 2022 AK DGGS Lidar: Twentymile River Watershed, AK alternateTitle: ak2022_twentymile_m10245_metadata date: (CI_Date) date: 2022 dateType: (CI_DateTypeCode) creation date: (CI_Date) date: 2023 dateType: (CI_DateTypeCode) publication identifier: (MD_Identifier) authority: (CI_Citation) title: NOAA/NMFS/EDM date: (inapplicable) code: Anchor: InPort Catalog ID 74359 citedResponsibleParty: (CI_ResponsibleParty) organisationName: (inapplicable) contactInfo: (CI_Contact) onlineResource: (CI_OnlineResource) linkage: https://www.fisheries.noaa.gov/inport/item/74359 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/geoid12b/10245/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://dggs.alaska.gov/webpubs/dggs/rdf/text/rdf2023_003.pdf protocol: WWW:LINK-1.0-http--link name: Lidar Report description: Link to the AK DGGS lidar report. function: (CI_OnLineFunctionCode) download role: (inapplicable) citedResponsibleParty: (CI_ResponsibleParty) organisationName: (inapplicable) contactInfo: (CI_Contact) onlineResource: (CI_OnlineResource) linkage: http://doi.org/10.14509/30959 protocol: WWW:LINK-1.0-http--link name: AK DGGS Products description: Link to the AK DGGS site to download all products for the 2022 Twentymile River Watershed lidar project. 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?m=10245&g=geoid12b 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: Lidar-derived elevation data for the Twentymile River watershed, Southcentral Alaska, collected August-October 2022, Raw Data File 2023-3, uses aerial lidar to produce a classified point cloud, digital surface model (DSM), digital terrain model (DTM), and intensity model of the Twentymile River watershed, Southcentral Alaska, during snow-free ground conditions from August to October 2022. The survey provides snow-free surface elevations for trail planning and assessing avalanche hazards, among other objectives. Ground control data were collected on August 31, 2022, and aerial lidar data were collected on multiple days from August 29 to October 14, 2022, and subsequently processed in a suite of geospatial processing software. These products are released as a Raw Data File with an open end-user license. All files can be downloaded from the Alaska Division of Geological & Geophysical Surveys website (http://doi.org/10.14509/30959). This metadata record references the data downloaded by the NOAA Office for Coastal Management (OCM) and processed to make it available for custom download from the NOAA Digital Coast Data Access Viewer (DAV) and for bulk download from S3 AWS. This data set contains point cloud data(' in LAZ (compressed LAS) format', ''). The data may have been reprojected or otherwise modified from the original data in an automated process. Disregard projection information in this abstract and refer to the spatial reference section. purpose: The orthoimage and elevation data were collected for assessing coastal hazards and changes. credit: The area of this survey is the traditional homelands of the Dena'ina people. We partnered with U.S. Forest Service to cost-share the acquisition of lidar data in an area of mutual interest. We thank Clearwater Air for their aviation expertise and contribution to these data products and the Alaska Division of Mining, Land, and Water for collecting ground control points. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government., Zechmann, J.M. Wikstrom Jones, Katreen Wolken, G.J. 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 2025-06-03 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/geoid12b/10245/supplemental/ak2022_twentymile_m10245.kmz fileDescription: This graphic displays the footprint for this lidar data set. fileType: kmz 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: 17.0 descriptiveKeywords: (MD_Keywords) keyword: CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA keyword: CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA > ALASKA keyword: VERTICAL LOCATION > LAND SURFACE type: (MD_KeywordTypeCode) place thesaurusName: (CI_Citation) title: Global Change Master Directory (GCMD) Location Keywords date: (missing) edition: 20.8 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: 17.2 descriptiveKeywords: (MD_Keywords) keyword: Airplane > Airplane type: (MD_KeywordTypeCode) platform thesaurusName: (CI_Citation) title: Global Change Master Directory (GCMD) Platform Keywords date: (missing) edition: 17.2 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: This data set was compiled dynamically. It will be removed 10 days after 2025-06-03 from the NOAA system. Cite As: OCM Partners, [Date of Access]: 2022 AK DGGS Lidar: Twentymile River Watershed, AK [Data Date Range], https://www.fisheries.noaa.gov/inport/item/74359. 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 otherConstraints: This data set was compiled dynamically. It will be removed 10 days after 2025-06-03 from the NOAA system. Access Constraints: This report, map, and/or dataset is available directly from the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys. resourceConstraints: (MD_LegalConstraints) useConstraints: (MD_RestrictionCode) otherRestrictions otherConstraints: This data set was compiled dynamically. It will be removed 10 days after 2025-06-03 from the NOAA system. Use Constraints: Any hard copies or published datasets utilizing these datasets shall clearly indicate their source. If the user has modified the data in any way, the user is obligated to describe the types of modifications the user has made. The user specifically agrees not to misrepresent these datasets, nor to imply that changes made by the user were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys. The State of Alaska makes no express or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product. 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. resourceConstraints: (MD_LegalConstraints) useLimitation: (MD_RestrictionCode) otherRestrictions otherConstraints: This data set was compiled dynamically. It will be removed 10 days after 2025-06-03 from the NOAA system. Distribution Liability: The State of Alaska makes no expressed or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product. 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 AK DGGS Lidar DEM: Twentymile River Watershed, AK date: (unknown) identifier: (MD_Identifier) authority: (CI_Citation) title: NOAA/NMFS/EDM date: (inapplicable) code: 74381 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: 74359 citedResponsibleParty: (CI_ResponsibleParty) organisationName: (inapplicable) contactInfo: (CI_Contact) onlineResource: (CI_OnlineResource) linkage: https://www.fisheries.noaa.gov/inportserve/waf/noaa/nos/ocmp/dmp/pdf/74359.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: -149.16 eastBoundLongitude: -148.557069 southBoundLatitude: 60.787275 northBoundLatitude: 61.082818 temporalElement: (EX_TemporalExtent) extent: TimePeriod: description: Dates of collection | Currentness: Ground Condition beginPosition: 2022-08-29 endPosition: 2022-08-30 temporalElement: (EX_TemporalExtent) extent: TimeInstant: description: Date of collection | Currentness: Ground Condition timePosition: 2022-09-02 temporalElement: (EX_TemporalExtent) extent: TimePeriod: description: Dates of collection | Currentness: Ground Condition beginPosition: 2022-09-04 endPosition: 2022-09-06 temporalElement: (EX_TemporalExtent) extent: TimeInstant: description: Date of collection | Currentness: Ground Condition timePosition: 2022-09-14 temporalElement: (EX_TemporalExtent) extent: TimeInstant: description: Date of collection | Currentness: Ground Condition timePosition: 2022-09-18 temporalElement: (EX_TemporalExtent) extent: TimeInstant: description: Date of collection | Currentness: Ground Condition timePosition: 2022-10-01 temporalElement: (EX_TemporalExtent) extent: TimeInstant: description: Date of collection | Currentness: Ground Condition timePosition: 2022-10-14 supplementalInformation: >classified_points: Classified point cloud data are provided in LAS format. Data are classified in accordance with ASPRS 2019 guidelines and contain return and intensity information. The average pulse spacing for non-noise returns is 26.9 cm and the average pulse density is 13.8 pts/m2. For ground points, the average point spacing is 59.6 cm and the average density is 2.82 pts/m2. Within the survey area and the scientific priority area, the average pulse spacing and density is 20.7 cm and 23.24 pts/m2, respectively, and the average ground point spacing and density is 64.4 cm and 2.41 pts/m2. >dsm: The DSM represents surface elevations, including heights of vegetation, buildings, powerlines, etc. The DSM is a single-band, 32-bit GeoTIFF file of 50-centimeter resolution, delivered in 1 km by 1 km tiles. No Data value is set to -9999. >dtm: The DTM represent bare earth elevations, excluding vegetation, bridges, buildings, etc. the DTM is single-band, 32-bit float GeoTIFF file, of 50-centimeter ('DTM'). No Data value is set to -9999. >dtm_detail: The detailed DTM represents bare earth elevations, excluding vegetation. The DTM is single-band, 32-bit float GeoTIFF file, of 20-cm resolution. This higher-resolution DTM file covers an area identified as a scientific priority. No Data value is set to -9999. >lidar_intensity: The lidar intensity image describes the relative amplitude of reflected signals contributing to the point cloud. Lidar intensity is primarily a function of scanned object reflectance in relation to the signal frequency, is dependent on ambient conditions, and is not necessarily consistent between separate scans. The intensity image is a single-band, 16-bit unsigned GeoTIFF file of 0.5-meter resolution. No Data value is set to -9999. >lidar_las_index: The LAS index file is a shapefile with polygons that serve as an index to the spatial location and extent of each point cloud (LAS) bin. return to top distributionInfo: (MD_Distribution) distributionFormat: (MD_Format) name: (inapplicable) version: (missing) fileDecompressionTechnique: Zip distributionFormat: (MD_Format) name: LAS/LAZ - LASer version: (missing) fileDecompressionTechnique: LAZ 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=10245/details/10245 protocol: WWW:LINK-1.0-http--link name: Customized Download description: Create custom data files by choosing data area, map projection, file format, etc. A new metadata will be produced to reflect your request using this record as a base. function: (CI_OnLineFunctionCode) download transferOptions: (MD_DigitalTransferOptions) onLine: (CI_OnlineResource) linkage: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid12b/10245/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 return to top dataQualityInfo: (DQ_DataQuality) scope: (DQ_Scope) level: (MD_ScopeCode) dataset report: (DQ_AbsoluteExternalPositionalAccuracy) nameOfMeasure: Horizontal Positional Accuracy evaluationMethodDescription: We did not measure horizontal accuracy for this collection. result: (missing) report: (DQ_AbsoluteExternalPositionalAccuracy) nameOfMeasure: Vertical Positional Accuracy evaluationMethodDescription: We measured a mean offset of -0.0048 m between 24 control points and the point cloud. Because of trivial offset, we did not perform any vertical transformation of the lidar point data. The non-vegetated vertical accuracy (NVA) of the point cloud ground class was found using a Triangulated Irregular Network approach. We calculated the project NVA to have a root mean square error (RMSE) of 6.7 cm. We evaluated the relative accuracy for this dataset as the interswath overlap consistency and measured it at 8.4 cm RMSE. result: (missing) report: (DQ_CompletenessCommission) nameOfMeasure: Completeness Report evaluationMethodDescription: This data relaease is complete. result: (missing) report: (DQ_ConceptualConsistency) nameOfMeasure: Conceptual Consistency evaluationMethodDescription: We visually inspected the imagery for data errors such as shifts, and seamline mismatches. Data quality is consistent throughout the survey, save for a gap in coverage in a deep valley in the northwest part of the survey area, and over some glaciated areas where there were few returns due to ground cover conditions. Ground point density varies throughout the survey and is illustrated in the acconpanying report. We provide higher resolution DTM files for the area of scientific interest. result: (missing) lineage: (LI_Lineage) statement: Data were collected by the Alaska Division of Geological and Geophysical Surveys (AK DGGS). The data were downloaded by the NOAA Office for Coastal Management (OCM) and processed to make it available for custom download from the NOAA Digital Coast Data Access Viewer (DAV) and for bulk download from S3 AWS. processStep: (LI_ProcessStep) description: Aerial photogrammetric survey - DGGS used a Riegl VUX1-LR laser scanner integrated with a global navigation satellite system (GNSS) and Northrop Grumman LN-200C inertial measurement unit (IMU) designed by Phoenix LiDAR Systems. The sensor can collect up to 820,000 points per second at a range of up to 150 m. The scanner operated with a pulse refresh rate of 200,000-400,000 pulses per second over forested terrain, and 50,000-100,000 pulses per second over alpine terrain, with a scan rate between 80 and 220 lines per second. We used a Cessna 180 fixed-wing aircraft to survey from an elevation of approximately 60-600 m above ground level, at a ground speed of approximately 40 m/s, and with a scan angle set from 80 to 280 degrees. The total survey area covers approximately 488 km2. The survey area was accessed by air from the Girdwood-Alyeska and Merrill Field airports in Girdwood and Anchorage. See table 1 for departure and return times and weather conditions. dateTime: DateTime: 2022-10-14T00:00:00 processStep: (LI_ProcessStep) description: Ground survey - The Alaska Division of Mining, Land, and Water (DMLW) collected ground control points on August 31, 2022. They deployed a Trimble R12 GNSS receiver at an unnamed survey marker (0.5 in steel rod in a 4 in pipe casing) offset from the south side of the Alaska Railroad Portage Depot parking lot. It provided a two-hour base station occupation and real-time kinematic (RTK) corrections to points they surveyed with a rover Trimble R12i GNSS receiver (internal antenna). DMLW collected 24 ground control points and check points to use for calibration and to assess the vertical accuracy of the point cloud. Most points were collected on bare earth or paved surfaces. However, ground control points 9, 17, 18, and 24 were collected in forest and shrubland. dateTime: DateTime: 2022-08-31T00:00:00 processStep: (LI_ProcessStep) description: Lidar dataset processing - We processed point data in SDCimport software for initial filtering and multiple-time-around (MTA) disambiguation. MTA errors, corrected in this process, result from ambiguous interpretations of received pulse time intervals and occur more frequently with higher pulse refresh rates. We processed Inertial Measurement Unit (IMU) and Global Navigation Satellite System (GNSS) data in Inertial Explorer, and we used Spatial Explorer software to integrate flightline information with the point cloud. We calibrated the point data at an incrementally precise scale of sensor movement and behavior, incorporating sensor velocity, roll, pitch, and yaw fluctuations throughout the survey. We created macros in Terrasolid software and classified points per the American Society for Photogrammetry and Remote Sensing (ASPRS) 2019 guidelines. Once classified, we applied a geometric transformation and converted the points from ellipsoidal heights to GEOID12B (Alaska) orthometric heights. We used ArcGIS Pro to derive raster products from the point cloud. A 50 cm DSM was interpolated from maximum return values from the ground, vegetation, bridge deck, and building classes using a binning method. A 50 cm DTM was interpolated from all ground class returns using a binning method and minimum values. An additional 20 cm DTM was produced for the scientific priority area using a triangulation interpolation. We produced an intensity image using average binning in ArcGIS Pro. dateTime: DateTime: 2022-01-01T00:00:00 processStep: (LI_ProcessStep) description: The NOAA Office for Coastal Management (OCM) downloaded 693 laz point data files from the Alaska Division of Geological and Geophysical Surveys (AK DGGS). The data were in UTM Zone 6 (NAD83 2011), meters coordinates and NAVD88 (Geoid12b) elevations in meters. The data were classified as: 1 - Unclassified, 2 - Ground, 3 - Low Vegetation (>/=0.05 m ,<0.5 m), 4 - Medium Vegetation (>/= 0.5 m, <3 m), 5 - High Vegetation (>/= 3 m, < /= 60 m), 7 - Low Noise, 17 - Bridge Decks, 18 - High Noise, 30 - Noise, Manually Classified. There were also points that were classified as 8 that were not listed in either the lidar report or in the provided metadata. These points were assumed to be Noise classes by OCM and this was confirmed by AK DGGS. OCM re-classified the Class 8 and Class 30 points to Class 18 - High Noise. OCM processed all classifications of points to the Digital Coast Data Access Viewer (DAV), the classes available on the DAV are: 1, 2, 3, 4, 5, 7, 17, 18. 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 laz files to: a. Re-classify points that were classified as 8 and 30 to Class 18 - High Noise b. Convert from orthometric (NAVD88) elevations to NAD83 (2011) ellipsoid elevations using the Geoid12b model c. Convert the laz files from UTM Zone 6 (NAD83 2011), meters coordinates to geographic coordinates d. Assign the geokeys, sort the data by gps time and zip the data to database and to S3 AWS. dateTime: DateTime: 2025-01-17T00:00:00 processor: (CI_ResponsibleParty) organisationName: Office for Coastal Management role: (CI_RoleCode) processor source: (LI_Source) sourceCitation: (CI_Citation) title: Data Downloaded from the AK DGGS date: (missing) citedResponsibleParty: (CI_ResponsibleParty) organisationName: AK DGGS contactInfo: (CI_Contact) onlineResource: (CI_OnlineResource) linkage: https://dggs.alaska.gov/webpubs/data/rdf2023_003_classified_points.zip protocol: WWW:LINK-1.0-http--link name: Data download zipfile for the 2022 AK DGGS Twentymile River Watershed lidar description: Source Citation URL function: (CI_OnLineFunctionCode) information role: (CI_RoleCode) publisher processStep: (LI_ProcessStep) description: The dataset has been mosaiced, reprojected, and clipped as needed from the original input files using PDAL and GDAL commands. dateTime: DateTime: 2025-06-03 processor: (CI_ResponsibleParty) individualName: NOAA Office for Coastal Management contactInfo: (CI_Contact) address: (CI_Address) electronicMailAddress: coastal.info@noaa.gov role: (CI_RoleCode) processor | |