Lidar-derived elevation data for the Alaska Peatland Experiment (APEX) plot, Bonanza Creek Experimental Forest, Interior Alaska, collected September 20, 2025

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

Frequently anticipated questions:


What does this data set describe?

Title:
Lidar-derived elevation data for the Alaska Peatland Experiment (APEX) plot, Bonanza Creek Experimental Forest, Interior Alaska, collected September 20, 2025
Abstract:
Lidar-derived elevation data for the Alaska Peatland Experiment (APEX) plot, Bonanza Creek Experimental Forest, Interior Alaska, collected September 20, 2025, Raw Data File 2026-17, provides mobile ground-based lidar to produce a classified point cloud, a digital surface model (DSM), a digital terrain model (DTM), and an intensity model of the Alaska Peatlands Experiment (APEX) plot in the Bonanza Creek Experimental Forest in Interior Alaska during leaf-on conditions. The Bonanza Creek Long Term Ecological Research Program is part of the Long Term Ecological Research (LTER) Network, which is supported by the United States National Science Foundation and comprises 26 research sites spanning multiple biomes worldwide. This survey provides snow-free surface elevations for monitoring permafrost evolution. Lidar data and ground control data were collected on September 20, 2025, and subsequently merged and processed using a suite of geospatial processing software. These data and accompanying documentation are released as a DGGS Raw Data File and are available from the DGGS website at http://doi.org/10.14509/32122.
Supplemental_Information:
boundaries:    A boundary, also known as an Area of Interest (AOI) or border, that defines the area covered by the data.	
classified_points:    Classified point cloud data are provided in LAZ format. Data are classified following ASPRS 2025 guidelines and contain return and intensity information. For classified ground points, the average point density is 308.1 pts/m2, and the average spacing is 5.7 cm.	
dsm:    The DSM represents surface elevations, including vegetation heights. The DSM is a single-band, 32-bit GeoTIFF file of 5-cm resolution. No Data value is set to -3.40282306074e+38 (32-bit, floating-point minimum).	
dtm:    The DTM represents bare-earth or snow-surface elevations, excluding vegetation. The DTM is a single-band, 32-bit GeoTIFF file of 5-cm resolution. No Data value is set to -3.40282306074e+38.	
footprints:    Footprints for tiled data.	
lidar_intensity:    The lidar intensity image describes the relative amplitude of reflected signals that contribute to the point cloud. Lidar intensity is (1) primarily a function of scanned object reflectance in relation to the signal frequency, (2) dependent on ambient conditions, and (3) not necessarily consistent between separate scans. The intensity image is a single-band, 32-bit GeoTIFF file of 5-cm resolution. No Data value is set to -3.40282306074e+38.
  1. How might this data set be cited?
    Zechmann, J.M., Salisbury, J.B., and Wikstrom Jones, K.M., 2026, Lidar-derived elevation data for the Alaska Peatland Experiment (APEX) plot, Bonanza Creek Experimental Forest, Interior Alaska, collected September 20, 2025: Raw Data File RDF 2026-17, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 13 p.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -148.324471
    East_Bounding_Coordinate: -148.319610
    North_Bounding_Coordinate: 64.697102
    South_Bounding_Coordinate: 64.695272
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 20-Sep-2025
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a raster 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: 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 coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest .00000001
      Ordinates (y-coordinates) are specified to the nearest .00000001
      Planar coordinates are specified in Meters
      The horizontal datum used is NAD83 (2011).
      The ellipsoid used is GRS 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, GEOID12B
      Altitude_Resolution: 0.500000
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    boundaries
    A boundary, also known as an Area of Interest (AOI) or border, that defines the area covered by the data. (Source: DGGS)
    classified_points
    Classified point cloud data are provided in LAZ format. Data are classified following ASPRS 2025 guidelines and contain return and intensity information. For classified ground points, the average point density is 308.1 pts/m2, and the average spacing is 5.7 cm. (Source: DGGS)
    dsm
    The DSM represents surface elevations, including vegetation heights. The DSM is a single-band, 32-bit GeoTIFF file of 5-cm resolution. No Data value is set to -3.40282306074e+38 (32-bit, floating-point minimum). (Source: DGGS)
    dtm
    The DTM represents bare-earth or snow-surface elevations, excluding vegetation. The DTM is a single-band, 32-bit GeoTIFF file of 5-cm resolution. No Data value is set to -3.40282306074e+38. (Source: DGGS)
    footprints
    Footprints for tiled data. (Source: DGGS)
    lidar_intensity
    The lidar intensity image describes the relative amplitude of reflected signals that contribute to the point cloud. Lidar intensity is (1) primarily a function of scanned object reflectance in relation to the signal frequency, (2) dependent on ambient conditions, and (3) not necessarily consistent between separate scans. The intensity image is a single-band, 32-bit GeoTIFF file of 5-cm resolution. No Data value is set to -3.40282306074e+38. (Source: DGGS)

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 survey area lies within the ancestral homelands of the Dene peoples of the lower Tanana River. This work was funded by the U.S. Geological Survey National Land Imaging Program. 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.
  3. To whom should users address questions about the data?
    Alaska Division of Geological & Geophysical Surveys
    Metadata Manager
    3354 College Road
    Fairbanks, AK
    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 (https://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible.

Why was the data set created?

This survey provides snow-free surface elevations for monitoring permafrost evolution. This information is essential for assessing hazards, informing risk-mitigation efforts, and supporting decision-making for communities and infrastructure.

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: 20-Sep-2025 (process 1 of 3)
    Ground survey - Ground control points were collected on September 20, 2025. We deployed a Trimble R12i GNSS base receiver and surveyed points using a rover Trimble R12i GNSS receiver/Mesa3 controller within the survey area. We collected 110 ground control points and checkpoints on boardwalk surfaces and corners, bog surfaces, tussock areas, forested areas, and tundra vegetation areas. For a GNSS base station occupation to later correct lidar survey lines, we set up a Trimble R12i in a field ~0.6 km northwest of the survey area. We processed and delivered all data in NAD83 (2011), UTM6N, and the vertical datum NAVD88 GEOID12B.
    Date: 20-Sep-2025 (process 2 of 3)
    Lidar survey - DGGS used a Riegl VUX1-LR22 laser scanner with a global navigation satellite system (GNSS) and a Northrop Grumman LN-200C inertial measurement unit (IMU) integrated by Phoenix LiDAR Systems. The sensor can collect up to 1,500,000 points per second at a range of 230 m, or a minimum of 50,000 points per second at 1,000 m (ranges assume greater than or equal to 20 percent natural reflectance). The scanner operated with a pulse refresh rate of 1,500,000 pulses per second at a scan rate of 200 revolutions per second. We walked the existing boardwalks at the site, using a backpack-mounted system to survey from approximately 2 meters above ground level, at a ground speed of approximately 0.8 m/s, and with a scan angle set to 10 to 350 degrees. The total survey area covers approximately 0.025 km2. The survey area was accessed by car from Fairbanks. Data was collected from 1:10 pm to 2:10 pm (AKDT). The weather throughout the survey was clear with no wind.
    Date: 2025 (process 3 of 3)
    Dataset processing - We processed point data in Spatial Explorer to apply initial filtering and multiple-time-around (MTA) disambiguation. MTA errors, which result from ambiguous interpretations of pulse time intervals, were corrected during this step. We processed IMU and GNSS data in Inertial Explorer and integrated traverse line information with the point cloud in Spatial Explorer. We calibrated the point data to account for sensor movement and behavior, including velocity, roll, pitch, and yaw fluctuations throughout the survey. For the lidar acquisition, the average pulse density is 116,860.5 pulses per square meter, and the average pulse spacing is 0.29 centimeters. We created a macro in Terrasolid software to classify points according to ASPRS 2025 guidelines. After classification, we applied a geometric transformation and converted ellipsoidal heights to GEOID12B (Alaska) orthometric heights. We derived raster products in ArcGIS Pro. A 5-cm DSM was interpolated from ground and vegetation classes using binning and maximum values. A 5-cm DTM was interpolated from ground-class returns using binning and minimum values. We also produced a 5-cm intensity image using average binning, with no normalization or corrections applied.
  3. What similar or related data should the user be aware of?
    Wolken, G.J., Hendricks, K.A., Daanen, R.P., Overbeck, J.R., Stevens, D.S.P., and Masterman, S.S., 2017, Alaska & climate change: Information Circular IC 64, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 2 p

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

  1. How well have the observations been checked?
    Not applicable
  2. How accurate are the geographic locations?
    The offset between the point cloud (visualized as a 2 cm resolution shaded relief using only ground and bridge deck point classes) and 27 horizontal ground control points was -10.1 cm easting and +13.0 cm northing. This was changed to -0.2 cm and -5.6 cm, respectively, by applying a seven-parameter affine transformation. To determine the horizontal accuracy of the corrected point cloud, we used 14 checkpoints and measured the offset between checkpoints and their respective locations in the corrected point cloud. The project's horizontal accuracy has a root-mean-square error (RMSE) of 10.2 cm in the east-west direction and 12.9 cm in the north-south direction.
  3. How accurate are the heights or depths?
    We measured a mean elevation offset of +12.5 cm between 15 control points and the point cloud. This offset was reduced to 1.0 cm in nonvegetated areas and 15.1 cm in vegetated areas by applying a constant vertical correction to the lidar point data. We used 15 nonvegetated and 39 vegetated checkpoints to determine the vertical accuracy of the point cloud ground class using a Triangulated Irregular Network (TIN) approach. The project's nonvegetated vertical accuracy has a root mean square error (RMSE) of 3.8 cm, and the vegetated vertical accuracy is 17.2 cm RMSE. We evaluated the relative accuracy for this dataset as the interswath overlap consistency, yielding an RMSE of 4.6 cm.
  4. Where are the gaps in the data? What is missing?
    This is a full-release dataset. There was no over-collect.
  5. How consistent are the relationships among the observations, including topology?
    Data quality is best nearest the traverse lines, which were limited to boardwalks. Areas far from boardwalks have relatively low point density due to line-of-sight shadows in the point cloud data.

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
    Metadata Manager
    3354 College Road
    Fairbanks, AK
    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 (https://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 2026-17
  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: 23-Jul-2026
Metadata author:
Alaska Division of Geological & Geophysical Surveys
Attn: Simone Montayne
Metadata Manager
3354 College Road
Fairbanks, AK
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
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:

Generated by mp version 2.9.50 on Thu Jul 23 11:04:55 2026