LiDAR data for Unalakleet, Alaska, collected in October 27, 2005

Metadata also available as - [Parseable text] - [XML]

Frequently anticipated questions:


What does this data set describe?

Title:
LiDAR data for Unalakleet, Alaska, collected in October 27, 2005
Abstract:
This report is a summary of a LiDAR data collection over the community of Unalakleet, in the Norton Sound region of Alaska. The original data were collected on October 27, 2005 by AeroMetric, Inc., under contract by Rodney P. Kinney and Associates, Inc. The complete, classified LiDAR dataset was purchased by the State of Alaska Division of Geological & Geophysical Surveys in 2013 in support of coastal vulnerability mapping efforts. For the purposes of open access to LiDAR datasets in coastal regions of Alaska, this collection is being released as a Raw Data File with an open end-user license.
Supplemental_Information:
The DGGS metadata standard extends the FGDC standard to include elements that are required to facilitate our internal data management. These elements, referred to as "layers," group and describe files that have intrinsic logical or topological relationships and correspond to subdirectories within the data distribution package. The metadata layer provides an FGDC metadata file and may include other documentation files. Attribute information for each data layer is described in this metadata file under the "Entity_and_Attribute_Information" section. Data layer contents:
point cloud data - all returns - classified:    Classified (ASPRS standard) LiDAR values for all returns (distributed in LAZ format)
las-index:    Vector data polygons that serve as an index to the spatial location and extent of each point cloud (LAS) bin
border:    A vector data polygon that encompasses the maximum geographic extent of the data observations
  1. How should this data set be cited?

    Southerland, L.E., and Kinsman, N.E.M., 2014, LiDAR data for Unalakleet, Alaska, collected in October 27, 2005: Raw Data File RDF 2014-2, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 12 p.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -160.834750
    East_Bounding_Coordinate: -160.748784
    North_Bounding_Coordinate: 63.917474
    South_Bounding_Coordinate: 63.844708

  3. What does it look like?

  4. Does the data set describe conditions during a particular time period?

    Calendar_Date: 2005
    Currentness_Reference: ground condition

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: digital-data, report

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a point data set.

    2. What coordinate system is used to represent geographic features?

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 4
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -159
      Latitude_of_Projection_Origin: 0
      False_Easting: 500000.000000
      False_Northing: 0

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.01
      Ordinates (y-coordinates) are specified to the nearest 0.01
      Planar coordinates are specified in meters

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.
      The flattening of the ellipsoid used is 1/298.257222101.

      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: NAVD88, derived using GEOID09
      Altitude_Resolution: 0.01
      Altitude_Distance_Units: Meters
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates

  7. How does the data set describe geographic features?

    point_cloud_data
    Data type: point cloud data - all returns - classified; Description: Classified (ASPRS standard) LiDAR values for all returns; File format: LAS 1.3, distributed in LAZ format (Source: AeroMetric, Inc.)

    rdf2014-2-las-index
    Data type: las-index; Description: Vector data polygons that serve as an index to the spatial location and extent of each point cloud (LAS) bin; File format: shapefile (Source: AeroMetric, Inc.)

    NAME
    Bin identification (Source: AeroMetric, Inc.)

    Alpha numeric values that uniquely identify each LAS bin

    rdf2014-2-border
    Data type: border; Description: A vector data polygon that encompasses the maximum geographic extent of the data observations; File format: shapefile (Source: AeroMetric, Inc.)


Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

    This publication is funded with qualified outer continental shelf oil and gas revenues by the Coastal Impact Assistance Program, U.S. Fish and Wildlife Service, U.S. Department of the Interior. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the opinions or policies of the U.S. Government. Mention of trade names or commercial products does not constitute their endorsement by the U.S. Government.

  3. To whom should users address questions about the data?

    Alaska Division of Geological & Geophysical Surveys
    GIS Manager
    3354 College Road
    Fairbanks, AK 99709-3707
    USA

    (907)451-5020 (voice)
    dggsgis@alaska.gov

    Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays


Why was the data set created?

This report is a summary of a LiDAR data collection over the community of Unalakleet, in the Norton Sound region of Alaska. The original data were collected on October 27, 2005 by AeroMetric, Inc., under contract by Rodney P. Kinney and Associates, Inc. The complete, classified LiDAR dataset was purchased by the State of Alaska Division of Geological & Geophysical Surveys in 2013 in support of coastal vulnerability mapping efforts. For the purposes of open access to LiDAR datasets in coastal regions of Alaska, this collection is being released as a Raw Data File with an open end-user license.


How was the data set created?

  1. From what previous works were the data drawn?

  2. How were the data generated, processed, and modified?

    Date: 2005 (process 1 of 7)
    Collection - The raw LiDAR data points were captured using AeroMetric's twin-engine Cessna equipped with a OPTECH 30/70 ALTM 70 kHz LiDAR acquisition system. The system includes differential GPS (DGPS) and inertial navigation systems (INS) to provide the necessary trajectory accuracy.

    Date: 2006 (process 2 of 7)
    Processing - The airborne trajectory solution was processed in Applanix's POSPac v. 4.4, which first computes a 2 Hz Post Processed Kinematic (PPK) DGPS trajectory, then integrates the 200 Hz inertial measurement unit data for a final smoothed best estimate of trajectory (SBET). This SBET is then integrated with the LiDAR pulse data, utilizing Optech's REALM software, for a final x,y,z 'point cloud' dataset in industry standard LAS (LiDAR Accuracy Standard) format in the NAD83, Universal Transverse Mercator (UTM), Zone 4 Meters coordinate system with ellipsoidal heights.

    Date: 2013 (process 3 of 7)
    Migration and calibration - For this delivery, AeroMetric gathered the necessary data from the Unalakleet archive drive. Using GeoCue (V2012.1.27.5), AeroMetric converted the LAS swath data to NAVD88 GEOID09, NAD83 UTM Zone 4. The archived LAS swath data lacked return and scan angle information. Individual points were classified based on return number. Using proprietary in-house software, AeroMetric was able to use these classifications and timestamps to calculate the point return fields. Polygons were digitized along flight line edges to re-class the geometrically unreliable points near the extreme edge of the swath to help with calibration. An in-situ calibration was performed using the data collect for this project. The dataset was classified in each line separately for ground and other common features between lines, such as building roofs. This dataset was processed in TerraSolid's TerraMatch (Version 11.001) to compute corrections for roll, pitch, heading, and mirror scale. These corrections are applied in order to minimize discrepancies between flight lines.

    Date: 2013 (process 4 of 7)
    Classification - AeroMetric preformed automated classification of the bare-earth data from the LiDAR point cloud using a series of algorithms customized for the types of terrain encountered in the project. This step was followed by manual classification of any data which appeared to be poorly classified using the automated methods. Breaklines were digitized along coast and water bodies that met project standards listed above.

    Date: 2013 (process 5 of 7)
    Verification - Rodney P. Kinney (RPK) and Associates provided AeroMetric with Post Processed Kinematic (PPK) Quality Assurance and Quality Control (QAQC) data, to check the vertical accuracy of these LiDAR data. The 2006 control file had to be traslated by AeroMetric from GEOID99 to GEOID09. A comparison between the QAQC and the LiDAR point data were made using TerraScan, to determine any vertical bias in the data. An adjustment of 0.21 meters was applied to the LiDAR data in order to match the provided QAQC data.

    Date: 2013 (process 6 of 7)
    Classified LAS 1.1 files - AeroMetric created classified LAS 1.1 files using the client provided tiling scheme. The points within each tile are sorted sequentially in order of acquisition, and have adjusted GPS timestamps. Note: that the Acquisition and Processing Report provided by AeroMetric incorrectly cites the deliverable format as LAS 1.3.

    Date: 2014 (process 7 of 7)
    File compression - LAS files were compressed to LAZ format to facilitate online distribution

  3. What similar or related data should the user be aware of?


How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

    Accuracy statements are based on areas of moderate terrain. Diminished accuracies are to be expected in areas of extreme terrain and dense vegetation. The accuracy of each point is expected to meet the vertical accuracy standard, however, derived products may be less accurate in extreme terrain and dense vegetation due to a lesser number of points defining the bare-earth in these areas. Questions regarding data accuracy can be best answered by AeroMetric/Quantum Spatial (Anchorage, Alaska) staff. The dataset was provided to us in LAS 1.1 format (not in LAS 1.3 format as noted int the delivery report.)

  2. How accurate are the geographic locations?

    Data products collected were acquired at or below 600 meters above mean terrain (AMT) and have a horizontal accuracy of 0.4 meters (per manufacturer's system specifications) with a nominal point spacing of .74 meters. No direct testing of the horizontal accuracy was feasible given this dataset.

  3. How accurate are the heights or depths?

    The bare-earth classified LiDAR data were compared to Rodney P. Kinney and Associates check points throughout the project area. A statistical summary of the elevation differences was completed.

  4. Where are the gaps in the data? What is missing?

    DGGS staff performed visual qualitative assessment to ensure data completeness. There are no void areas or missing data. Users should note that this dataset was acquired in 2005 and subsequently migrated to more modern specifications in 2013. Questions regarding data quality and completeness can be best answered by AeroMetric/Quantum Spatial (Anchorage, Alaska) staff. In addition to the classified point cloud data and delivery report provided by this release, AeroMetric also provided to DGGS: trajectory values, unclassified point cloud data, and a statistical summary of the elevation differences between LiDAR values and the ground survey points that were collected by Rodney P. Kinney and Associates)

  5. How consistent are the relationships among the observations, including topology?

    Quality control and quality assurance ground survey points were collected by Rodney P. Kinney and Associates and supplied to AeroMetric.


How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

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.

  1. Who distributes the data set? (Distributor 1 of 1)

    Alaska Division of Geological & Geophysical Surveys
    3354 College Road
    Fairbanks, AK 99709-3707
    USA

    (907)451-5020 (voice)
    (907)451-5050 (FAX)
    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.
  2. What's the catalog number I need to order this data set?

    RDF 2014-2

  3. What legal disclaimers am I supposed to read?

    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.

  4. How can I download or order the data?


Who wrote the metadata?

Dates:
Last modified: 03-Apr-2014
Metadata author:
Alaska Division of Geological & Geophysical Surveys
Metadata Manager
3354 College Road
Fairbanks, AK 99709-3707
USA

(907)451-5020 (voice)

Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:


Generated by mp version 2.9.21 on Thu Apr 3 15:38:29 2014