2019 AK DGGS Lidar DEM: Utqiagvik - Atqasuk, Alaska

Lidar-derived elevation data for the Utqiagvik-Atqasuk region, Alaska, collected August 2019, Raw Data File 2022-10, provides classified point cloud, digital terrain model (DTM), surface model (DSM), and intensity model data for the communities of Utqiagvik and Atqasuk and surrounding areas. The data were collected in support of the Alaska Strategic Transportation and Resources (ASTAR) program for the purpose of investigating the potential for future road infrastructure connecting the communities. Aerial lidar data were collected between August 19 and 23, 2019, and subsequently processed using a suite of geospatial processing software. These products are released as a Raw Data File with an open end-user license. All files can be downloaded from the Alaska Division of Geological & Geophysical Surveys website (http://doi.org/10.14509/30870).

The NOAA Office for Coastal Management (OCM) downloaded this data set from this AK DGGS site:

https://elevation.alaska.gov/

These files were processed to make the data available for custom and bulk download from the NOAA Digital Coast Data Access Viewer (DAV) . The total number of files downloaded and processed was 1.

In addition to these bare earth Digital Elevation Model (DEM) data, the lidar point data that these DEM data were created from, are also available. These data are available for custom download at the link provided in the URL section of this metadata record.

The data were collected in support of the Alaska Strategic Transportation and Resources (ASTAR) program for the purpose of investigating the potential for future road infrastructure connecting the communities.

>classified points: Classified point cloud data are 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 ground point spacing was 34 cm and the average density was 8.51 pts/m^2

>digital surface model: The DSM represents surface elevations including heights of vegetation, buildings, bridges, and other structures. 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).

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.

Any conclusions drawn from the analysis of this information are not the responsibility of NOAA, the Office for Coastal Management or its partners.

Data is available online for bulk and custom downloads.

None

Users should be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its limitations.

Horizontal accuracy was not measured for this collection.

A mean offset of -25.5 cm was measured between 19 control points and point cloud ground returns. This offset was reduced to 0.001 cm by performing a vertical transformation of the lidar point data. Thirty-three 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 5.2 cm. Relative accuracy for this dataset was evaluated as the interswath overlap consistency and was measured at 0.95 cm RMSE. See the accompanying report for check points and additional detail.

This is a partial data release and contains all data collected except from the seven flightlines shown in figure 1 of the accompanying report. There is no over collect. The data quality is consistent throughout the survey.

DGGS visually inspected the orthoimage for data errors such as shifts, seamline mismatches, and water noise overlapping land. There were no significantly erroneous areas that required repair.

Data were collected by the Alaska Division of Geological and Geophysical Surveys (AK DGGS). OCM downloaded the data from the Alaska DGGS Elevation Portal and processed the data to be available for custom and bulk download from the NOAA Digital Coast Data Access Viewer (DAV).