| 2022 AK DGGS Lidar DEM: Twentymile River Watershed, AK | referenceSystemInfo|
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| (MI_Metadata) fileIdentifier: gov.noaa.nmfs.inport:74381 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: 2026-03-04T19:17:17 metadataStandardName: ISO 19115-2 Geographic Information - Metadata Part 2 Extensions for imagery and gridded data metadataStandardVersion: ISO 19115-2:2009(E) return to top referenceSystemInfo: (MD_ReferenceSystem) referenceSystemIdentifier: (RS_Identifier) code: EPSG::6335 return to top referenceSystemInfo: (MD_ReferenceSystem) referenceSystemIdentifier: (RS_Identifier) code: EPSG::5703 return to top identificationInfo: (MD_DataIdentification) citation: (CI_Citation) title: 2022 AK DGGS Lidar DEM: Twentymile River Watershed, AK 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 74381 citedResponsibleParty: (CI_ResponsibleParty) organisationName: (inapplicable) contactInfo: (CI_Contact) onlineResource: (CI_OnlineResource) linkage: https://www.fisheries.noaa.gov/inport/item/74381 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://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/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). 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. 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 > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION > DIGITAL ELEVATION/TERRAIN MODEL (DEM) 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: DEMs - 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 AK DGGS Lidar DEM: Twentymile River Watershed, AK [Data Date Range], https://www.fisheries.noaa.gov/inport/item/74381. 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: 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: 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: 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: Twentymile River Watershed, AK date: (unknown) identifier: (MD_Identifier) authority: (CI_Citation) title: NOAA/NMFS/EDM date: (inapplicable) code: 74359 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: 74381 citedResponsibleParty: (CI_ResponsibleParty) organisationName: (inapplicable) contactInfo: (CI_Contact) onlineResource: (CI_OnlineResource) linkage: https://www.fisheries.noaa.gov/inportserve/waf/noaa/nos/ocmp/dmp/pdf/74381.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) grid 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: 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: 2022-09-02 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: GeoTIFF 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=10246/details/10246 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. function: (CI_OnLineFunctionCode) download transferOptions: (MD_DigitalTransferOptions) onLine: (CI_OnlineResource) linkage: https://noaa-nos-coastal-lidar-pds.s3.us-east-1.amazonaws.com/dem/AK_Twentymile_DEM_2022_10246/index.html protocol: WWW:LINK-1.0-http--link name: Bulk Download description: Bulk download of data files in GeoTiff format, UTM Zone 6 NAD83 (2011) (EPSG: 6335), meters coordinates and NAVD88 elevations in meters (EPSG: 5703). 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 1 GeoTiff data file 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 bare earth raster files were at a 0.5 meter grid spacing. OCM performed the following processing on the data for Digital Coast storage and provisioning purposes: 1. Used internal an script to assign the EPSG codes (Horizontal EPSG: 6335 and Vertical EPSG: 5703) to the GeoTiff formatted file. 2. Copied the file to https. dateTime: DateTime: 2025-01-22T00:00:00 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_dtm.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 | |