Identification_Information: Citation: Citation_Information: Originator: Daanen, R.P. Originator: Wolken, G.J. Originator: Wikstrom Jones, Katreen Originator: Herbst, A.M. Publication_Date: 2021 Title: Lidar-derived elevation data for upper Barry Arm, Southcentral Alaska, June 26, 2020 Geospatial_Data_Presentation_Form: report, point cloud, GeoTIFF Series_Information: Series_Name: Raw Data File Issue_Identification: RDF 2021-1 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 9 p. Online_Linkage: https://doi.org/10.14509/30589 Description: Abstract: The Alaska Division of Geological & Geophysical Surveys (DGGS) used aerial lidar to produce a classified point cloud, digital terrain model (DTM), surface model (DSM), and intensity model of land areas in northern Barry Arm, northwest Prince William Sound, Alaska, during near snow-free ground conditions on June 26, 2020. The goal of the survey is to provide high quality, modern topographic data in the recently deglacierized part of Barry Arm where significant landslide hazards exist. Aerial lidar and ground control data were collected on June 26, 2020, and subsequently processed in Terrasolid and ArcGIS. Ground control was collected on June 26, 2020, as well. All files can be downloaded free of charge from the Alaska Division of Geological & Geophysical Surveys website (http://doi.org/10.14509/30589). Purpose: The goal of the survey is to provide high quality, modern topographic data in the recently deglacierized part of Barry Arm where significant landslide hazards exist. This data release is one of a series of DGGS publications to present elevation data. Supplemental_Information: >classified point cloud data: Classified point cloud data is provided in this collection in compressed LAZ format. Data are classified in accordance with ASPRS 2014 guidelines and contain return and intensity information. The average pulse spacing was 7.2 cm and the average density was 12.05 pts/m2. >digital surface model: The DSM represents surface elevations including heights of vegetation, buildings, bridges, etc. The DSM is a single band, 32-bit GeoTIFF file, with a ground sample distance of 1 meter. No Data value is set to -3.40282306074e+038. >digital terrain model: The DTM represents surface elevations of ground surfaces, excluding vegetation, bridges, buildings, etc. The DTM is a single-band, 32-bit float GeoTIFF file, with a ground sample distance of 1 meter. No Data value is set to -3.40282306074e+038. >lidar intensity image: The lidar intensity image describes the relative amplitude of reflected signals contributing to the point cloud. Lidar intensity is largely 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, 32-bit float GeoTIFF file with a ground sample distance of 1 meter. No Data value is set to -3.40282306074e+038 (32-bit, floating-point minimum). >hydro-enforced digital terrain model: The hydro-enforced DTM represents bare earth surfaces which have undergone a selective "flattening" process, where elevation values for any hydrologic features, as well as any hydrologic obstacles (bridges, culverts, etc.), are replaced with neighboring pixel values. The hydro-enforced DTM is a single-band, 32-bit float GeoTIFF file, with a ground sample distance of 1 meter. No Data value is set to -3.40282306074e+038. Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 20200626 Currentness_Reference: ground condition Status: Progress: complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -148.214985 East_Bounding_Coordinate: -148.060743 North_Bounding_Coordinate: 61.188625 South_Bounding_Coordinate: 61.077423 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme: Theme_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Theme_Keyword: Debris Avalanche Theme_Keyword: Debris Flow Theme_Keyword: Digital Elevation Model Theme_Keyword: Digital Surface Model (DSM) Theme_Keyword: Digital Terrain Model Theme_Keyword: Engineering Theme_Keyword: Engineering Geology Theme_Keyword: Geologic Theme_Keyword: Geology Theme_Keyword: Geomorphology Theme_Keyword: Geotechnical Theme_Keyword: Glacial Geology Theme_Keyword: Glacial Geomorphology Theme_Keyword: Glacial Processes Theme_Keyword: Landslide Theme_Keyword: Landslide Susceptibility Theme_Keyword: LiDAR Theme_Keyword: Point Cloud Data Theme_Keyword: Remote Sensing Theme_Keyword: Rock Avalanche Theme_Keyword: Rockfall Theme_Keyword: Slope Theme_Keyword: Slope Instability Theme_Keyword: Surficial Theme_Keyword: Surficial Geology Theme_Keyword: Topography Theme_Keyword: Tsunami Theme_Keyword: Unconsolidated Deposits Theme_Keyword: Web Service Place: Place_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Place_Keyword: Barry Arm Place_Keyword: Barry Glacier Place_Keyword: College Fjord Place_Keyword: Esther Island Place_Keyword: Harriman Fiord Place_Keyword: Passage Canal Place_Keyword: Port Wells Place_Keyword: Whittier 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 (see contact information below). 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. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: Alaska Division of Geological & Geophysical Surveys Contact_Position: Metadata Manager Contact_Address: Address_Type: mailing and physical Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: (907)451-5020 Contact_Facsimile_Telephone: (907)451-5050 Contact_Electronic_Mail_Address: dggspubs@alaska.gov Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays Contact_Instructions: Please view our website (https://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible. Data_Set_Credit: These data products were funded by the State of Alaska and collected and processed by DGGS. We thank Clearwater Air and Alpine Air for their aviation expertise and contribution to these data products. Cross_Reference: Citation_Information: Originator: Stevens, D.S.P. Originator: Wolken, G.J. Originator: Hubbard, T.D. Originator: Hendricks, K.A. Publication_Date: 2018 Title: Landslides in Alaska Series_Information: Series_Name: Information Circular Issue_Identification: IC 65 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 2 p Online_Linkage: https://doi.org/10.14509/29849 Cross_Reference: Citation_Information: Originator: Stevens, D.S.P. Publication_Date: 2019 Title: The Engineering Geology section at DGGS Series_Information: Series_Name: Information Circular Issue_Identification: IC 76 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 2 p Online_Linkage: https://doi.org/10.14509/30122 Cross_Reference: Citation_Information: Originator: Timm, Kristin Originator: Wolken, G.J. Publication_Date: 2017 Title: Deglacierization and the development of glacier-related hazards Series_Information: Series_Name: Information Circular Issue_Identification: IC 63 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 3 p Online_Linkage: https://doi.org/10.14509/29752 Cross_Reference: Citation_Information: Originator: Wolken, G.J. Originator: Hendricks, K.A. Originator: Daanen, R.P. Originator: Overbeck, J.R. Originator: Stevens, D.S.P. Originator: Masterman, S.S. Publication_Date: 2017 Title: Alaska & climate change Series_Information: Series_Name: Information Circular Issue_Identification: IC 64 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 2 p Online_Linkage: https://doi.org/10.14509/29781 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: Not applicable Logical_Consistency_Report: Relative accuracy for this dataset was evaluated as the interswath overlap consistency and was measured at 8.3 cm RMSE. The data quality is consistent throughout the survey. Completeness_Report: This data release is complete, and there is no over collect except for aircraft turns that were eliminated from the dataset. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Horizontal accuracy was not measured for this collection. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: A mean offset of -19.7 cm was measured between 84 control points and the point cloud (appendix 1). This offset was reduced to -0.6 cm by performing a vertical transformation of the lidar point data. Twenty-two check points were used to determine the non-vegetated vertical accuracy (NVA) of the point cloud ground class, using a TIN-based approach. Project NVA was calculated to have a root mean square error (RMSE) of 7.7 cm. See accompanying report for more detail. Lineage: Process_Step: Process_Description: Airborne 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). The lidar integration system was designed by Phoenix LiDAR Systems. The sensor is capable of collecting up to 820,000 points per second over a distance of 150 m. This survey was flown with a pulse refresh rate between 200,000 and 600,000 pulses per second at a scan rate between 80 and 150 lines per second. This survey was flown with an average elevation of 200 m above ground level and a ground speed of approximately 36 m/s with a fixed-wing aircraft configuration, using a Cessna 180 aircraft. The scan angle was set from 80 to 280 degrees. The total area surveyed was approximately 40 km2. Flight take-off occurred at 10:15am from Merrill Field airport in Anchorage, Alaska, and landing occurred at 4:00 pm. The aircraft landed at the airstrip in Girdwood, Alaska, once during the survey. Process_Date: 20200626 Process_Step: Process_Description: Ground survey - Ground control and check points were collected on June 26, 2020. A Trimble R10-2 GNSS receiver with internal antenna was deployed on the ridge near the center of the study and provided a base station occupation and real-time kinematic (RTK) corrections to points surveyed with a rover Trimble R10-2 GNSS receiver (internal antenna). A total of 106 ground control points and check points were collected to be used for calibration and assessment of the vertical accuracy of the point cloud. All points were collected on bare earth or minimally vegetated surface. Process_Date: 20200626 Process_Step: Process_Description: Lidar dataset processing - Point data were processed in SDCimport software for initial filtering and multiple-time-around (MTA) disambiguation. MTA errors, corrected in this process, are the result of imprecise interpretations of received pulse time intervals and occur more frequently with higher pulse refresh rates. Inertial Measurement Unit (IMU) and Global Navigation Satellite System (GNSS) data were processed in Inertial Explorer and used to integrate flightline information with the point cloud in Spatial Explorer software. The point data were calibrated at an incrementally precise scale of sensor movement and behavior, incorporating sensor velocity, roll, pitch, and yaw fluctuations throughout the survey. Points were classified in accordance with American Society for Photogrammetry and Remote Sensing (ASPRS) 2014 guidelines, using macros designed in Terrasolid software. Careful attention was given to the interpolation of the project's ground surface to compensate for inconsistent penetration through low vegetation as a function of the scan angle. Once classified, points underwent a geometric transformation and were converted from ellipsoidal heights to GEOID12B (Alaska) orthometric heights. Raster products were derived from the point cloud using ArcMap. The DTM was interpolated from all ground class returns using a TIN-based method. The DTM was also used to produce a separate hydro-enforced raster based on a digitized shoreline. The DSM was likewise interpolated from only the first return points using a TIN-based method. An intensity image was also produced in ArcMap, using closest-to-mean binning. Process_Date: 2020 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: raster Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Grid_Coordinate_System: Grid_Coordinate_System_Name: Universal Transverse Mercator Universal_Transverse_Mercator: UTM_Zone_Number: 6 Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.999600 Longitude_of_Central_Meridian: -147 Latitude_of_Projection_Origin: 0 False_Easting: 500000.000000 False_Northing: 0 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: .00000001 Ordinate_Resolution: .00000001 Planar_Distance_Units: Meters Geodetic_Model: Horizontal_Datum_Name: NAD83 (2011) Ellipsoid_Name: GRS 80 Semi-major_Axis: 6378137 Denominator_of_Flattening_Ratio: 298.257222101000025 Vertical_Coordinate_System_Definition: Altitude_System_Definition: Altitude_Datum_Name: NAVD88, GEOID12B Altitude_Resolution: 0.001 Altitude_Distance_Units: meters Altitude_Encoding_Method: Explicit elevation coordinate included with horizontal coordinates Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: classified point cloud data Entity_Type_Definition: Classified point cloud data is provided in this collection in compressed LAZ format. Data are classified in accordance with ASPRS 2014 guidelines and contain return and intensity information. The average pulse spacing was 7.2 cm and the average density was 12.05 pts/m2. Entity_Type_Definition_Source: Alaska Division of Geological & Geophysical Surveys (DGGS) Entity_Attribute_Layer_Name: classified point cloud data Detailed_Description: Entity_Type: Entity_Type_Label: digital surface model Entity_Type_Definition: The DSM represents surface elevations including heights of vegetation, buildings, bridges, etc. The DSM is a single band, 32-bit GeoTIFF file, with a ground sample distance of 1 meter. No Data value is set to -3.40282306074e+038. Entity_Type_Definition_Source: Alaska Division of Geological & Geophysical Surveys (DGGS) Entity_Attribute_Layer_Name: digital surface model Detailed_Description: Entity_Type: Entity_Type_Label: digital terrain model Entity_Type_Definition: The DTM represents surface elevations of ground surfaces, excluding vegetation, bridges, buildings, etc. The DTM is a single-band, 32-bit float GeoTIFF file, with a ground sample distance of 1 meter. No Data value is set to -3.40282306074e+038. Entity_Type_Definition_Source: Alaska Division of Geological & Geophysical Surveys (DGGS) Entity_Attribute_Layer_Name: digital terrain model Detailed_Description: Entity_Type: Entity_Type_Label: lidar intensity image Entity_Type_Definition: The lidar intensity image describes the relative amplitude of reflected signals contributing to the point cloud. Lidar intensity is largely 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, 32-bit float GeoTIFF file with a ground sample distance of 1 meter. No Data value is set to -3.40282306074e+038 (32-bit, floating-point minimum). Entity_Type_Definition_Source: Alaska Division of Geological & Geophysical Surveys (DGGS) Entity_Attribute_Layer_Name: lidar intensity image Detailed_Description: Entity_Type: Entity_Type_Label: hydro-enforced digital terrain model Entity_Type_Definition: The hydro-enforced DTM represents bare earth surfaces which have undergone a selective "flattening" process, where elevation values for any hydrologic features, as well as any hydrologic obstacles (bridges, culverts, etc.), are replaced with neighboring pixel values. The hydro-enforced DTM is a single-band, 32-bit float GeoTIFF file, with a ground sample distance of 1 meter. No Data value is set to -3.40282306074e+038. Entity_Type_Definition_Source: Alaska Division of Geological & Geophysical Surveys (DGGS) Entity_Attribute_Layer_Name: hydro-enforced digital terrain model Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: Alaska Division of Geological & Geophysical Surveys Contact_Position: Metadata Manager Contact_Address: Address_Type: mailing and physical Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: (907)451-5020 Contact_Facsimile_Telephone: (907)451-5050 Contact_Electronic_Mail_Address: dggspubs@alaska.gov Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays Contact_Instructions: Please view our website (https://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible. Resource_Description: RDF 2021-1 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. Standard_Order_Process: Non-digital_Form: DGGS publications are available as free online downloads or you may purchase paper hard-copies or digital files on CD/DVD or other digital storage media by mail, phone, fax, or email from the DGGS Fairbanks office. To purchase this or other printed reports and maps, contact DGGS by phone (907-451-5020), e-mail (dggspubs@alaska.gov), or fax (907-451-5050). Payment accepted: Cash, check, money order, VISA, or MasterCard. Turnaround time is 1-2 weeks unless special arrangements are made and an express fee is paid. Shipping charge will be the actual cost of postage and will be added to the total amount due. Contact us for the exact shipping amount. Fees: Contact DGGS for current pricing Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: report point-cloud GeoTIFF Format_Version_Date: 20210126 Format_Information_Content: classified point cloud data, digital surface model, digital terrain model, lidar intensity image, and hydro-enforced digital terrain model Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://doi.org/10.14509/30589 Fees: Free download Metadata_Reference_Information: Metadata_Date: 20210127 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: Alaska Division of Geological & Geophysical Surveys Contact_Person: Simone Montayne Contact_Position: Metadata Manager Contact_Address: Address_Type: mailing and physical Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: (907)451-5020 Contact_Facsimile_Telephone: (907)451-5050 Contact_Electronic_Mail_Address: dggspubs@alaska.gov Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Use_Constraints: If the user has modified the data in any way they are obligated to describe the types of modifications they have performed in the supporting metadata file. User specifically agrees not to imply that changes they made were approved by the Alaska Department of Natural Resources or Division of Geological & Geophysical Surveys. Metadata_Extensions: Online_Linkage: https://dggs.alaska.gov/metadata/dggs.ext Profile_Name: dggs metadata extensions