Identification_Information: Citation: Citation_Information: Originator: Daanen, R.D. Originator: Wolken, G.J. Originator: Herbst, A.M. Publication_Date: 2020 Title: High-resolution lidar data from the west Susitna area, Southcentral, Alaska Geospatial_Data_Presentation_Form: imagery Series_Information: Series_Name: Raw Data File Issue_Identification: RDF 2020-5 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 7 p. Online_Linkage: http://doi.org/10.14509/30455 Description: Abstract: The Alaska Division of Geological & Geophysical Surveys used airborne lidar to produce a digital terrain model (DTM) and digital surface model (DSM) for the west Susitna area, about 65 km (40 mi) west of Wasilla, Alaska. Airborne data were collected November 4-10, 2019, and subsequently processed in Terrasolid and ArcGIS. Ground control data were concurrently collected by DGGS. All files can be downloaded free of charge from the Alaska Division of Geological & Geophysical Surveys website (http://doi.org/10.14509/30455). Purpose: This dataset includes point cloud data and two 32-bit raster elevation models that cover an area of interest for proposed infrastructure development in the west Susitna region. Supplemental_Information: >point cloud data: Classified lidar values. Points were classified in accordance with ASPRS 2014 guidelines. >digital surface model: DSMs represent surface elevations, as they appear to the naked eye. They include the heights of vegetation, buildings, bridges, etc. The DSM is a single band, 32-bit GeoTif file, with a ground sample distance of .5 meters. No Data value is set to -3.40282306074e+038. >digital terrain model: DTMs represent 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 .5 meters. No Data value is set to -3.40282306074e+038. Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2017 Currentness_Reference: ground condition Status: Progress: complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -151.770872 East_Bounding_Coordinate: -150.594323 North_Bounding_Coordinate: 61.941196 South_Bounding_Coordinate: 61.106528 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme: Theme_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Theme_Keyword: Aerial Theme_Keyword: Aerial Geology Theme_Keyword: Digital Surface Model (DSM) Theme_Keyword: Digital Terrain Model Theme_Keyword: Elevation Theme_Keyword: Engineering Theme_Keyword: Engineering Geology Theme_Keyword: Geologic Theme_Keyword: Geology Theme_Keyword: Geomorphology Theme_Keyword: Geotechnical Theme_Keyword: LiDAR Theme_Keyword: Point Cloud Data Theme_Keyword: Raster Image Theme_Keyword: Remote Sensing Theme_Keyword: Surface Theme_Keyword: Surficial Theme_Keyword: Surficial Geology Theme_Keyword: Topography Place: Place_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Place_Keyword: Alexander Creek Place_Keyword: Bates Creek Place_Keyword: Bear Creek Place_Keyword: Beluga River Place_Keyword: Canyon Creek Place_Keyword: Canyon Lake Place_Keyword: Clear Creek Place_Keyword: Coffee Creek Place_Keyword: Deep Creek Place_Keyword: Dog Lake Place_Keyword: Friday Creek Place_Keyword: Olson Creek Place_Keyword: Pretty Creek Place_Keyword: Quartz Creek Place_Keyword: Saturday Creek Place_Keyword: Skwentna River Place_Keyword: Susitna Place_Keyword: Talachulitna Creek Place_Keyword: Talachulitna River Place_Keyword: Texas Creek Place_Keyword: Threemile Creek Place_Keyword: Thursday Creek Place_Keyword: Trail Creek Place_Keyword: Tukallah Lake Place_Keyword: Viapan Lake Place_Keyword: Wasilla Place_Keyword: Wolverine Creek 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 Data_Set_Credit: These data were collected and processed by the Alaska Division of Geological and Geophysical Surveys staff with funding from the Alaska Industrial Development and Export Authority. Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: Airborne data were collected on November 4-10, 2019. Weather conditions were generally sub-optimal throughout the survey, requiring operations to take place in thick fog and low-lying clouds, at the risk of increased levels of noise in the product. Snow was present across the majority of the study area surface and accumulated throughout the survey period, especially in the northernmost section. Weather conditions and snow cover resulted in variability of point density throughout the study area. See accompanying report for further discussion of data verification procedures. Logical_Consistency_Report: The tests and processing methods used to ensure data consistency are described in the accompanying report. Completeness_Report: Elevation surfaces interpolated from areas with a point density of fewer than 1pts/m^2 were classified as nodata. This data release is complete. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Trimble R8 and R9 RTK GPS systems were used to collect ground control points (GCPs). Seventy-five checkpoints were used to calculate a vertical accuracy of 39 cm RMSE. Internal consistency for the point cloud data was measured at 6.5cm across the project. Points were adjusted for accuracy, according to OPUS corrections, in Trimble Business Center. See accompanying report for a table of checkpoints and further discussion of factors impacting the certainty of data locations. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: Seventy-five checkpoints were used to calculate a vertical accuracy of 39 cm RMSE. Relative accuracy was evaluated as the interswath consistency and was measured at 2.1 cm RMSE. The quality of the data is the average elevation compared to an independent dataset. The second aspect of the quality of the data is related to point density distribution over the survey area. The average point density is 10.23 points per square meter. A table of checkpoints and errors is provided in the accompanying report. Lineage: Process_Step: Process_Description: Data acquisition - DGGS operates a Riegl VUX1-LR lidar integrated with a GNSS and Northrop Grumman IMU system. The integration 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 at a pulse rate between 200,000 and 400,000 pulses per second, at a scan rate between 80 and 150 loops per second. The average pulse spacing was 31.27 cm and the average density was 10.23 pts/m2. This survey was flown with an average elevation of 1,000 m above ground level and a ground speed of approximately 40 m/s with a fixed wing aircraft configuration, using a Cessna 185 aircraft. The scan angle was set from 55 to 305 degrees. Airborne data were collected November 4-10, 2019. Weather conditions were generally sub-optimal throughout the survey, requiring operations to take place in thick fog and low-lying clouds, at the risk of increased levels of noise in the product. Snow was present across the majority of the study area surface and accumulated throughout the survey period, especially in the northernmost section. Process_Date: 2019 Process_Step: Process_Description: Point classification - Point cloud data was run through SDCimport software for initial filtering and disambiguation of errors. Once filtered, the point cloud and trajectory data were fused together by integrating IMU and GPS information. Points were classified in accordance with ASPRS 2014 guidelines. A significant amount of noise, due to snow and weather conditions during the survey, was separated from the rest of the data and designated to class 8, model keypoints. All classified points were vertically transformed to maintain a mean offset fewer than 10 cm from surveyed ground control. Process_Date: 2020 Process_Step: Process_Description: Raster products - Raster products were produced from las files in ArcMap and were clipped according to a lidar point density threshold of 8pts/m2. DTM and DSM were created using a tin-based method. 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: 5 Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.999600 Longitude_of_Central_Meridian: -153 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: North American Datum of 1983 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: 0.5 Altitude_Distance_Units: meters Altitude_Encoding_Method: Explicit elevation coordinate included with horizontal coordinates Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Attribute_Layer_Name: point cloud data Entity_Type_Label: point cloud data Entity_Type_Definition: Classified lidar values. Points were classified in accordance with ASPRS 2014 guidelines. Entity_Type_Definition_Source: Alaska Division of Geological & Geophysical Surveys (DGGS) Detailed_Description: Entity_Type: Entity_Attribute_Layer_Name: digital surface model Entity_Type_Label: digital surface model Entity_Type_Definition: DSMs represent surface elevations, as they appear to the naked eye. They include the heights of vegetation, buildings, bridges, etc. The DSM is a single band, 32-bit GeoTif file, with a ground sample distance of .5 meters. No Data value is set to -3.40282306074e+038. Entity_Type_Definition_Source: Alaska Division of Geological & Geophysical Surveys (DGGS) and National Oceanic & Atmospheric Administration Detailed_Description: Entity_Type: Entity_Attribute_Layer_Name: digital terrain model Entity_Type_Label: digital terrain model Entity_Type_Definition: DTMs represent 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 .5 meters. No Data value is set to -3.40282306074e+038. Entity_Type_Definition_Source: Alaska Division of Geological & Geophysical Surveys (DGGS) and National Oceanic & Atmospheric Administration 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 Resource_Description: RDF 2020-5 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: imagery Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://doi.org/10.14509/30455 Fees: Free download Metadata_Reference_Information: Metadata_Date: 20200624 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Person: Simone Montayne 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 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: http://www.dggs.alaska.gov/metadata/dggs.ext Profile_Name: dggs metadata extensions