Identification_Information: Citation: Citation_Information: Originator: Hubbard, T.D. Originator: Braun, M.L. Originator: Westbrook, R.E. Originator: Gallagher, P.E. Publication_Date: 2011 Title: High-resolution lidar data for infrastructure corridors, Anchorage Quadrangle, Alaska Geospatial_Data_Presentation_Form: raster digital data Series_Information: Series_Name: Raw Data File Issue_Identification: RDF 2011-3L Publication_Information: Publication_Place: Fairbanks, AK USA Publisher: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys Online_Linkage: http://dx.doi.org/10.14509/23024 Larger_Work_Citation: Citation_Information: Originator: Hubbard, T.D. Originator: Koehler, R.D. Originator: Combellick, R.A. Publication_Date: 2011 Title: High-resolution lidar data for Alaska infrastructure corridors Series_Information: Series_Name: Raw Data File Issue_Identification: RDF 2011-3 Publication_Information: Publication_Place: Fairbanks, AK USA Publisher: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys Online_Linkage: http://dx.doi.org/10.14509/22722 Description: Abstract: In advance of design, permitting, and construction of a pipeline to deliver North Slope natural gas to out-of-state customers and Alaska communities, the Division of Geological & Geophysical Surveys (DGGS) has acquired lidar (Light Detection and Ranging) data along proposed pipeline routes, nearby areas of infrastructure, and regions where significant geologic hazards have been identified. Lidar data will serve multiple purposes, but have primarily been collected to (1) evaluate active faulting, slope instability, thaw settlement, erosion, and other engineering constraints along proposed pipeline routes, and (2) provide a base layer for the state-federal GIS database that will be used to evaluate permit applications and construction plans. The highest-hit digital surface models (DSM) represent the earth's surface with all vegetation and human-made structures included. Purpose: Provide high resolution terrain elevation and land cover elevation data. Supplemental_Information: This metadata file was written to document and describe, as a whole, all of the highest-hit digital surface model files generated for this project. The highest-hit download package also includes the original metadata provided by Watershed Sciences, Inc. These metadata files may provide additional useful information that is specific to each file. The metadata files provided by Watershed Sciences, Inc. have not been reviewed for accuracy or compliance with FGDC standards. In addition to information found in the metadata files, specific information about accuracy and quality of lidar data can be found in quality control reports provided by DOGAMI and delivery reports provided by Watershed Sciences, Inc. Individual reports were provided for each delivery set and have been combined by DGGS into comprehensive quality control and delivery reports. These documents are organized according to how data were delivered to DGGS. A description of how information pertaining to downloadable files can be found in the quality control and delivery reports is located in the directory with the reports. The DGGS metadata standard extends the FGDC standard to include several elements that are required to facilitate internal data management. These elements (referred to as 'layers') relate individual data items to a common dataset. This dataset describes a single layer titled: >hh The highest-hit DSMs represent the earth's surface with all vegetation and human-made structures included. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 2010 Ending_Date: 2011 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: As needed Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -150 East_Bounding_Coordinate: -147 North_Bounding_Coordinate: 62 South_Bounding_Coordinate: 61 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme: Theme_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Theme_Keyword: Alaska Pipeline Theme_Keyword: Gasline Theme_Keyword: Geomorphology Theme_Keyword: Lidar Theme_Keyword: Proposed Natural Gas Pipeline Theme_Keyword: Remote Sensing Theme_Keyword: Raster Image Theme_Keyword: Highest Hit Digital Surface Model (DSM) Place: Place_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Place_Keyword: Anchorage Quadrangle Place_Keyword: Alaska Highway Corridor Place_Keyword: Alaska, State of Place_Keyword: Trans-Alaska Pipeline Access_Constraints: The datasets are 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: GIS Data Manager/GIS Analyst Contact_Address: Address_Type: mailing and physical address Address: 3354 College Rd City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: 907-451-5029 Contact_Voice_Telephone: 907-451-5020 Data_Set_Credit: Data collection was supported by funding from the Department of Natural Resources (DNR), Division of Geological & Geophysical Surveys (DGGS), the Alaska Gas Pipeline Project Office, the Office of the Federal Coordinator, and the Alaska Gasline Development Corporation (AGDC). Lidar data were collected and processed by Watershed Sciences, Inc. of Corvallis, OR. Survey data were collected by McClintock Land Associates of Eagle River, AK. Lidar data and derivative products were checked for quality, completeness, and accuracy by State of Oregon Department of Geology & Mineral Industries based in Portland, OR. Native_Data_Set_Environment: Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 9.3.1.3000 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: Absolute accuracy refers to the mean vertical offset of lidar data relative to measured ground-control points (GCP) obtained throughout the lidar sampling area. Ground control points were collected by McClintock Land Associates, a licensed surveying company, to be used as control comparison with lidar elevations. Refer to the lidar delivery report and lidar QC report for more details on the accuracy of the lidar data for each delivery area, including a comparison of GCP elevations with bare-earth digital elevation model elevations. The accuracy of the highest-hit surface model data is partly dependant on the positional accuracy of the lidar data. Development of the highest-hit surface model involved classification of buildings and structures through automated point processing algorithms and subsequent manual inspection and editing during the ground model creation. This process served as an accuracy check of the data. Logical_Consistency_Report: Lidar data have been examined to ensure that overlapping flight lines have consistent elevation values. Project specifications require that lidar consistency, measured as vertical offsets between adjacent flight lines, must average less than 0.15 meters. Refer to the lidar QC report and the lidar delivery report for statistics from consistency analyses for individual delivery sets. Flight lines have been examined to ensure that there was at least 60% sidelap and that there are no data gaps. Shaded relief, lidar slope, and bare-earth digital elevation model (DEM) images have been visually inspected for data errors such as pits, border artifacts, gaps, and shifting. All grids were loaded and inspected for outlier/erroneous percent cover values. All file naming conventions and formats have been checked for consistency. Completeness_Report: Lidar data have been checked for accuracy and completeness. Please refer to the lidar delivery report and lidar QC report for details about data accuracy completeness for individual delivery sets. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: True horizontal accuracy is regarded as a product of the lidar ground footprint. Lidar is referenced to co-acquired GPS base station data that have accuracies far greater than the value of the lidar footprint. The ground footprint is equal to 1/3333rd of the above - ground flying height. The ground footprint for data collected for this project exceeds typical accuracy of ground control used to reference the lidar data (less than 0.01 meters). Project specifications require the lidar footprint to be between 0.15 and 0.40 meters. Refer to the lidar QC report and lidar delivery report for additional information on horizontal accuracy for individual delivery areas. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: Vertical accuracy refers to the elevation difference between measured GPS control data and lidar digital elevation models. Project specifications require the root mean square vertical offset to be less than 0.2 meters. The highest-hit DSM represents the earth's surface including vegetation points, and buildings, where the vertical accuracy is a function of the accuracy of the bare-earth digital elevation model and the accuracy of lidar vegetation returns and human-made structures. Please see the lidar QC report and lidar delivery report for specific information about accuracy and quality of lidar data, including a comparison of GCP elevations with bare-earth digital elevation model elevations. Lineage: Process_Step: Process_Description: Acquisition: The lidar data were collected between September and October 2010 and between May and July 2011. The survey used the Leica ALS60 system. Near-nadir scan angles were used to increase penetration of vegetation to ground surfaces. Ground-level GPS and aircraft IMU were collected during the flight. Process_Date: 2010 and 2011 Process_Step: Process_Description: Processing lidar data: (1) Flight lines and data were reviewed to ensure complete coverage of the study area and positional accuracy of the laser points. (2) Laser point-return coordinates were computed using ALS Post Processor software, IPAS Pro GPS/INS software, and Waypoint GPS, based on independent data from the lidar system, IMU, and aircraft. (3) The raw lidar file was assembled into flight lines per return with each point having an associated x, y, and z coordinate. (4) Visual inspection of swath-to-swath laser point consistencies in the study area were used to perform manual refinements of system alignment. (5) Custom algorithms were designed to evaluate points between adjacent flight lines. Automated system alignment was computed based on randomly selected swath-to-swath accuracy measurements that consider elevation, slope, and intensities. Specifically, refinement in the combination of system pitch, roll, and yaw-offset parameters optimize internal consistency. (6) Noise (e.g., pits and birds) was filtered using ALS postprocessing software, based on known elevation ranges, and included the removal of any cycle slips. Process_Date: 2010, 2011, 2012 Process_Step: Process_Description: Hydro-flattening: A combination of automated and manual detection and adjustment techniques was used to identify lake boundaries and water levels for closed water bodies with a surface area > 150 square meters. Boundary polygons were developed using an algorithm that weights lidar-derived slopes, intensities, and return densities to detect the lake edge. Once detected, lake edges were manually reviewed and edited in a 3-D environment, and polygons were created with elevations computed from the filtered lidar returns. During the initial ground-modeling process returns from the water surface within each polygon were filtered and inspected for false low points. The elevation of each lake was computed as 5 cm above the minimum elevation of filtered-water surface cells within the lake polygon. Lake-boundary polygons were then incorporated into the final terrain model and enforced as hard break-lines. The initial ground classified-points falling within lake polygons were reclassified as water points and omitted from the final bare-earth DEM. Process_Date: 2010, 2011, 2012 Process_Step: Process_Description: Creation of bare-earth DEMs: (1) The TerraScan software suite was used to classify near-ground points. Geometric constraints were used to remove all points not near the earth. The resulting bare-earth ground model was then visually inspected and additional ground modeling was performed in site-specific areas to improve ground detail. (2) The corrected and filtered return points were compared to the real-time kinematic (RTK) ground survey points collected to verify the vertical and horizontal accuracies. (3) Points were output as laser points and TINed GRIDed surfaces. Process_Date: 2011, 2012 Process_Step: Process_Description: The highest-hit DSMs were derived from LiDAR data using the highest-hit method. Process_Date: 2010, 2011 Process_Step: Process_Description: A metadata file was created to generally describe data acquisition of lidar and also to describe the creation of highest-hit DSM images for the entire project. Process_Date: 2012 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Grid Cell 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: 0.000000 False_Easting: 500000.000000 False_Northing: 0.000000 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: row and column Coordinate_Representation: Abscissa_Resolution: 1.000000 Ordinate_Resolution: 1.000000 Planar_Distance_Units: meters Planar_Coordinate_Layer_Name: hh Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1983 Ellipsoid_Name: Geodetic Reference System 80 Semi-major_Axis: 6378137 Denominator_of_Flattening_Ratio: 298.257222 Vertical_Coordinate_System_Definition: Altitude_System_Definition: Altitude_Datum_Name: North American Vertical Datum of 1988 Altitude_Resolution: 0.0000001 Altitude_Distance_Units: meters Altitude_Encoding_Method: Attribute values Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: hh Entity_Type_Definition: Image of digital surface model representing percent highest-hit Entity_Type_Definition_Source: this report Entity_Attribute_Layer_Name: hh Overview_Description: Entity_and_Attribute_Overview: There are no attributes other than the encoded values for easting and northing coordinates. Entity_and_Attribute_Detail_Citation: this report Overview_Description_Layer_Name: hh Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys 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 (http://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 2011-3L Distribution_Liability: The State of Alaska makes no express or implied warranties (including warranties of merchantability and fitness) with respect to the character, function, or capabilities of the electronic services 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, any failure thereof, or otherwise, and in no event will the State of Alaska's liability to the requester or anyone else exceed the fee paid for the electronic service or product. Standard_Order_Process: Non-digital_Form: Current publication is not available on paper. To purchase 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. Fees: contact DGGS for current pricing Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: GRID Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://dx.doi.org/10.14509/23024 Fees: Free download Custom_Order_Process: 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 over the counter, by mail, phone, fax, or email from the DGGS Fairbanks office. 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 exact shipping amount. Metadata_Reference_Information: Metadata_Date: 20120301 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Metadata manager Contact_Address: Address_Type: mailing and physical Address: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: 907-451-5020 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 this metadata file in any way, the user is obligated to describe the types of modifications the user has made. User specifically agrees not to misrepresent this metadata file, 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. Metadata_Extensions: Online_Linkage: http://www.dggs.alaska.gov/metadata/dggs.ext Profile_Name: dggs metadata extensions