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Item Identification
Keywords
Physical Location
Data Set Info
Support Roles
Extents
Spatial Info
Access Info
Distribution Info
URLs
Data Quality
Lineage
Catalog Details

Summary

Short Citation
OCM Partners, 2024: 2020 AK DGGS Lidar DEM: Barry Arm, Alaska, https://www.fisheries.noaa.gov/inport/item/67836.
Full Citation Examples

Abstract

The Alaska Division of Geological & Geophysical Surveys (DGGS) used aerial lidar to produce a classified point cloud, digital terrain model (DTM), surface model (DSM), and intensity model of land areas in northern Barry Arm, northwest Prince William Sound, Alaska, during near snow-free ground conditions on June 26, 2020. The goal of the survey is to provide high quality, modern topographic data in the recently deglacierized part of Barry Arm where significant landslide hazards exist. Aerial lidar and ground control data were collected on June 26, 2020, and subsequently processed in Terrasolid and ArcGIS. Ground control was collected on June 26, 2020, as well. All files can be downloaded free of charge from the Alaska Division of Geological & Geophysical Surveys website (http://doi.org/10.14509/30589).

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. NOAA OCM noted that there are artifact areas along some of the borders of the data set.

Distribution Information

  • Create custom data files by choosing data area, map projection, file format, etc. A new metadata will be produced to reflect your request using this record as a base.

  • GeoTIFF

    Bulk download of data files in the original coordinate system.

Access Constraints:

None

Use Constraints:

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be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions.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.

Controlled Theme Keywords

COASTAL ELEVATION, DIGITAL ELEVATION/TERRAIN MODEL (DEM), elevation, geoscientificInformation, TERRAIN ELEVATION

Child Items

No Child Items for this record.

Contact Information

Point of Contact
NOAA Office for Coastal Management (NOAA/OCM)
coastal.info@noaa.gov
(843) 740-1202

Metadata Contact
NOAA Office for Coastal Management (NOAA/OCM)
coastal.info@noaa.gov
(843) 740-1202

Extents

Geographic Area 1

-148.214985° W, -148.060743° E, 61.188625° N, 61.077423° S

Time Frame 1
2020-06-26

Item Identification

Title: 2020 AK DGGS Lidar DEM: Barry Arm, Alaska
Short Name: ak2020_barry_dem_m9579_metadata
Status: Completed
Creation Date: 2020
Publication Date: 2021
Abstract:

The Alaska Division of Geological & Geophysical Surveys (DGGS) used aerial lidar to produce a classified point cloud, digital terrain model (DTM), surface model (DSM), and intensity model of land areas in northern Barry Arm, northwest Prince William Sound, Alaska, during near snow-free ground conditions on June 26, 2020. The goal of the survey is to provide high quality, modern topographic data in the recently deglacierized part of Barry Arm where significant landslide hazards exist. Aerial lidar and ground control data were collected on June 26, 2020, and subsequently processed in Terrasolid and ArcGIS. Ground control was collected on June 26, 2020, as well. All files can be downloaded free of charge from the Alaska Division of Geological & Geophysical Surveys website (http://doi.org/10.14509/30589).

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. NOAA OCM noted that there are artifact areas along some of the borders of the data set.

Purpose:

The goal of the survey is to provide high quality, modern topographic data in the recently deglacierized part of Barry Arm where significant landslide hazards exist. This data release is one of a series of DGGS publications to present elevation data.

Supplemental Information:

>classified point cloud data: Classified point cloud data is 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 pulse spacing was 7.2 cm and the average density was 12.05 pts/m2.

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

>hydro-enforced digital terrain model: The hydro-enforced DTM represents bare earth surfaces which have undergone a selective "flattening" process, where elevation values for any hydrologic features, as well as any hydrologic obstacles (bridges, culverts, etc.), are replaced with neighboring pixel values. The hydro-enforced 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.

Keywords

Theme Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Science Keywords
EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION
Global Change Master Directory (GCMD) Science Keywords
EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION > DIGITAL ELEVATION/TERRAIN MODEL (DEM)
Global Change Master Directory (GCMD) Science Keywords
EARTH SCIENCE > OCEANS > COASTAL PROCESSES > COASTAL ELEVATION
ISO 19115 Topic Category
elevation
ISO 19115 Topic Category
geoscientificInformation
UNCONTROLLED
Alaska Division of Geological & Geophysical Surveys Debris Avalanche
Alaska Division of Geological & Geophysical Surveys Debris Flow
Alaska Division of Geological & Geophysical Surveys Glacial Geology
Alaska Division of Geological & Geophysical Surveys Glacial Geomorphology
Alaska Division of Geological & Geophysical Surveys Glacial Processes
Alaska Division of Geological & Geophysical Surveys Landslide
Alaska Division of Geological & Geophysical Surveys LiDAR
Alaska Division of Geological & Geophysical Surveys Remote Sensing
Alaska Division of Geological & Geophysical Surveys Rock Avalanche
Alaska Division of Geological & Geophysical Surveys Rockfall
Alaska Division of Geological & Geophysical Surveys Slope Instability
Alaska Division of Geological & Geophysical Surveys Tsunami
Alaska Division of Geological & Geophysical Surveys Unconsolidated Deposits

Spatial Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Location Keywords
CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA
Global Change Master Directory (GCMD) Location Keywords
CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA > ALASKA
Global Change Master Directory (GCMD) Location Keywords
VERTICAL LOCATION > LAND SURFACE
UNCONTROLLED
Alaska Division of Geological & Geophysical Surveys Barry Glacier
Alaska Division of Geological & Geophysical Surveys College Fjord
Alaska Division of Geological & Geophysical Surveys Esther Island
Alaska Division of Geological & Geophysical Surveys Harriman Fjord
Alaska Division of Geological & Geophysical Surveys Passage Canal
Alaska Division of Geological & Geophysical Surveys Port Wells
Alaska Division of Geological & Geophysical Surveys Whittier

Instrument Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Instrument Keywords
LIDAR > Light Detection and Ranging

Platform Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Platform Keywords
Airplane > Airplane

Physical Location

Organization: Office for Coastal Management
City: Charleston
State/Province: SC

Data Set Information

Data Set Scope Code: Data Set
Data Set Type: Elevation
Maintenance Frequency: None Planned
Data Presentation Form: Model (digital)
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.

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

Data Set Credit: These data products were funded by the State of Alaska and collected and processed by DGGS. We thank Clearwater Air and Alpine Air for their aviation expertise and contribution to these data products., Daanen, R.P. Wolken, G.J. Wikstrom Jones, Katreen Herbst, A.M.

Support Roles

Data Steward

CC ID: 1183330
Date Effective From: 2022
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Distributor

CC ID: 1183329
Date Effective From: 2022
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Metadata Contact

CC ID: 1183331
Date Effective From: 2022
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Point of Contact

CC ID: 1183332
Date Effective From: 2022
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address: coastal.info@noaa.gov
Phone: (843) 740-1202
URL: https://coast.noaa.gov

Extents

Currentness Reference: Ground Condition

Extent Group 1

Extent Group 1 / Geographic Area 1

CC ID: 1298484
W° Bound: -148.214985
E° Bound: -148.060743
N° Bound: 61.188625
S° Bound: 61.077423

Extent Group 1 / Time Frame 1

CC ID: 1298483
Time Frame Type: Discrete
Start: 2020-06-26

Spatial Information

Spatial Representation

Representations Used

Grid: Yes

Reference Systems

Reference System 1

CC ID: 1298480

Coordinate Reference System

CRS Type: Vertical
EPSG Code: EPSG:5703
EPSG Name: NAVD88 height
See Full Coordinate Reference System Information

Reference System 2

CC ID: 1298481

Coordinate Reference System

CRS Type: Projected
EPSG Code: EPSG:6335
EPSG Name: NAD83(2011) / UTM zone 6N
See Full Coordinate Reference System Information

Access Information

Security Class: Unclassified
Data Access Procedure:

Data is available online for bulk and custom downloads.

Data Access Constraints:

None

Data Use Constraints:

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.

Distribution Information

Distribution 1

CC ID: 1183336
Start Date: 2022-09-06
End Date: Present
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=9579/details/9579
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2022 - Present)
File Name: Customized Download
Description:

Create custom data files by choosing data area, map projection, file format, etc. A new metadata will be produced to reflect your request using this record as a base.

File Type (Deprecated): Zip
Compression: Zip

Distribution 2

CC ID: 1183337
Start Date: 2022-09-06
End Date: Present
Download URL: https://noaa-nos-coastal-lidar-pds.s3.us-east-1.amazonaws.com/dem/AK_Barry_Arm_DEM_2020_9579/index.html
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2022 - Present)
File Name: Bulk Download
Description:

Bulk download of data files in the original coordinate system.

File Type (Deprecated): GeoTIFF
Distribution Format: GeoTIFF

URLs

URL 1

CC ID: 1183327
URL: https://coast.noaa.gov/
Name: NOAA's Office for Coastal Management (OCM) website
URL Type:
Online Resource
File Resource Format: HTML
Description:

Information on the NOAA Office for Coastal Management (OCM)

URL 2

CC ID: 1183328
URL: https://coast.noaa.gov/dataviewer/
Name: NOAA's Office for Coastal Management (OCM) Data Access Viewer (DAV)
URL Type:
Online Resource
File Resource Format: HTML
Description:

The Data Access Viewer (DAV) allows a user to search for and download elevation, imagery, and land cover data for the coastal U.S. and its territories. The data, hosted by the NOAA Office for Coastal Management, can be customized and requested for free download through a checkout interface. An email provides a link to the customized data, while the original data set is available through a link within the viewer.

URL 3

CC ID: 1183488
URL: https://dggs.alaska.gov/webpubs/dggs/rdf/text/rdf2021_003.pdf
Name: Lidar Report
URL Type:
Online Resource
File Resource Format: pdf
Description:

Link to the lidar report.

Data Quality

Horizontal Positional Accuracy:

Horizontal accuracy was not measured for this collection.

Vertical Positional Accuracy:

A mean offset of -19.7 cm was measured between 84 control points and the point cloud (appendix 1). This offset was reduced to -0.6 cm by performing a vertical transformation of the lidar point data. Twenty-two 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 7.7 cm. See accompanying report for more detail.

Completeness Report:

This data release is complete, and there is no over collect except for aircraft turns that were eliminated from the dataset.

Conceptual Consistency:

Relative accuracy for this dataset was evaluated as the interswath overlap consistency and was measured at 8.3 cm RMSE. The data quality is consistent throughout the survey.

Lineage

Lineage Statement:

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).

Sources

Alaska Division of Geological and Geophysical Surveys (AK DGGS)

CC ID: 1298475
Contact Role Type: Originator
Contact Type: Organization
Contact Name: AK DGGS
Citation URL: https://elevation.alaska.gov/
Citation URL Name: AK DGGS Elevation Portal

Process Steps

Process Step 1

CC ID: 1298476
Description:

Airborne survey - DGGS used a Riegl VUX1-LR laser scanner integrated with a global navigation satellite system (GNSS) and Northrop Grumman LN-200C inertial measurement unit (IMU). The lidar integration system 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 with a pulse refresh rate between 200,000 and 600,000 pulses per second at a scan rate between 80 and 150 lines per second. This survey was flown with an average elevation of 200 m above ground level and a ground speed of approximately 36 m/s with a fixed-wing aircraft configuration, using a Cessna 180 aircraft. The scan angle was set from 80 to 280 degrees. The total area surveyed was approximately 40 km2. Flight take-off occurred at 10:15am from Merrill Field airport in Anchorage, Alaska, and landing occurred at 4:00 pm. The aircraft landed at the airstrip in Girdwood, Alaska, once during the survey.

Process Date/Time: 2020-06-26 00:00:00

Process Step 2

CC ID: 1298477
Description:

Ground survey - Ground control and check points were collected on June 26, 2020. A Trimble R10-2 GNSS receiver with internal antenna was deployed on the ridge near the center of the study and provided a base station occupation and real-time kinematic (RTK) corrections to points surveyed with a rover Trimble R10-2 GNSS receiver (internal antenna). A total of 106 ground control points and check points were collected to be used for calibration and assessment of the vertical accuracy of the point cloud. All points were collected on bare earth or minimally vegetated surface.

Process Date/Time: 2020-06-26 00:00:00

Process Step 3

CC ID: 1298478
Description:

Lidar dataset processing - Point data were processed in SDCimport software for initial filtering and multiple-time-around (MTA) disambiguation. MTA errors, corrected in this process, are the result of imprecise interpretations of received pulse time intervals and occur more frequently with higher pulse refresh rates. Inertial Measurement Unit (IMU) and Global Navigation Satellite System (GNSS) data were processed in Inertial Explorer and used to integrate flightline information with the point cloud in Spatial Explorer software. The point data were calibrated at an incrementally precise scale of sensor movement and behavior, incorporating sensor velocity, roll, pitch, and yaw fluctuations throughout the survey. Points were classified in accordance with American Society for Photogrammetry and Remote Sensing (ASPRS) 2014 guidelines, using macros designed in Terrasolid software. Careful attention was given to the interpolation of the project's ground surface to compensate for inconsistent penetration through low vegetation as a function of the scan angle. Once classified, points underwent a geometric transformation and were converted from ellipsoidal heights to GEOID12B (Alaska) orthometric heights. Raster products were derived from the point cloud using ArcMap. The DTM was interpolated from all ground class returns using a TIN-based method. The DTM was also used to produce a separate hydro-enforced raster based on a digitized shoreline. The DSM was likewise interpolated from only the first return points using a TIN-based method. An intensity image was also produced in ArcMap, using closest-to-mean binning.

Process Date/Time: 2020-01-01 00:00:00

Process Step 4

CC ID: 1298479
Description:

The NOAA Office for Coastal Management (OCM) downloaded 1 raster DEM file in GeoTiff format from the Alaska DGGS Elevation Portal. The data were in UTM Zone 6 NAD83 (2011), meters coordinates and NAVD88 (Geoid12B) elevations in meters. The bare earth raster file was at a 1 meter grid spacing. NOAA OCM noted that there are artifact areas along some of the borders of the data set.

OCM performed the following processing on the data for Digital Coast storage and provisioning purposes:

1. Used internal an script to assign the EPSG codes (Horizontal EPSG: 6335 and Vertical EPSG: 5703) to the GeoTiff formatted files.

2. Copied the files to https.

Process Date/Time: 2022-09-06 00:00:00
Process Contact: Office for Coastal Management (OCM)

Catalog Details

Catalog Item ID: 67836
GUID: gov.noaa.nmfs.inport:67836
Metadata Record Created By: Rebecca Mataosky
Metadata Record Created: 2022-09-06 20:43+0000
Metadata Record Last Modified By: Kirk Waters
Metadata Record Last Modified: 2024-01-10 19:27+0000
Metadata Record Published: 2024-01-10
Owner Org: OCMP
Metadata Publication Status: Published Externally
Do Not Publish?: N
Metadata Last Review Date: 2022-09-06
Metadata Review Frequency: 1 Year
Metadata Next Review Date: 2023-09-06