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Keywords
Physical Location
Data Set Info
Support Roles
Extents
Spatial Info
Access Info
Distribution Info
URLs
Data Quality
Data Management
Lineage
Related Items
Catalog Details

Summary

Browse Graphic

Short Citation
OCM Partners, 2024: 2018 AK DGGS Lidar DEM: Turnagain Pass, AK, https://www.fisheries.noaa.gov/inport/item/67892.
Full Citation Examples

Abstract

The State of Alaska Division of Geological & Geophysical Surveys (DGGS) used lidar to produce a digital terrain model (DTM) and digital surface model (DSM) of Turnagain Pass, southcentral Alaska, during snow-free ground conditions. This dataset includes point cloud data, a 32-bit digital terrain model and digital surface model, and an intensity image covering Turnagain Pass located southeast of Anchorage within the Chugach National Forest on the Kenai Peninsula in southcentral Alaska. The lidar and Global Navigation Satellite System (GNSS) data were collected on September 2, 2018, and processed using Terrasolid. This data collection is released as a Raw Data File with an open end-user license. All files can be downloaded free of charge from the Alaska Division of Geological & Geophysical Surveys website (http://doi.org/10.14509/30567).

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

https://elevation.alaska.gov/

These file was 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.

Distribution Information

  • Create custom data files by choosing data area, product type, map projection, file format, datum, etc. A new metadata will be produced to reflect your request using this record as a base. Change to an orthometric vertical datum is one of the many options.

  • GeoTIFF

    Bulk download of data files in GeoTiff format, UTM Zone 6 NAD83 (2011) (EPSG: 6335), meters coordinates and orthometric heights in meters (EPSG: 5703).

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be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions.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

-149.331846° W, -149.022184° E, 60.866217° N, 60.707115° S

Time Frame 1
2018-09-02

Item Identification

Title: 2018 AK DGGS Lidar DEM: Turnagain Pass, AK
Status: Completed
Creation Date: 2018
Publication Date: 2021
Abstract:

The State of Alaska Division of Geological & Geophysical Surveys (DGGS) used lidar to produce a digital terrain model (DTM) and digital surface model (DSM) of Turnagain Pass, southcentral Alaska, during snow-free ground conditions. This dataset includes point cloud data, a 32-bit digital terrain model and digital surface model, and an intensity image covering Turnagain Pass located southeast of Anchorage within the Chugach National Forest on the Kenai Peninsula in southcentral Alaska. The lidar and Global Navigation Satellite System (GNSS) data were collected on September 2, 2018, and processed using Terrasolid. This data collection is released as a Raw Data File with an open end-user license. All files can be downloaded free of charge from the Alaska Division of Geological & Geophysical Surveys website (http://doi.org/10.14509/30567).

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

https://elevation.alaska.gov/

These file was 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.

Purpose:

The goal of the survey is to provide snow-free surface elevations for deriving snow depth distribution models with repeat surveys during snow-covered surface conditions. This data release is one of a series of DGGS publications to present elevation data.

Supplemental Information:

>classified point cloud data: The ground-classified point cloud has an average point spacing of 43 cm (43 cm on the ground in open alpine areas and 32 cm below dense vegetation in the valley) and an average point density of 2.3 points per square meter.

>digital surface model: The DSM represents surface elevations, for example heights of vegetation, buildings, bridges, etc. The DSM is a single band, 32-bit GeoTIFF file, with a ground sample distance of 50 cm. No Data value is set to -3.40282306074e+038.

>digital terrain model: The DTM represents 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 50 cm. No Data value is set to -3.40282306074e+038.

>lidar intensity image: The intensity image represents the return strengths of the first return laser pulses. The intensity image is a single band, 32-bit GeoTIFF file, with a ground sample distance of 50 centimeter and normalized to the 0-255 range. 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

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 Bench Creek
Alaska Division of Geological & Geophysical Surveys Bertha Creek
Alaska Division of Geological & Geophysical Surveys Center Creek
Alaska Division of Geological & Geophysical Surveys East Fork Sixmile Creek
Alaska Division of Geological & Geophysical Surveys Granite Creek
Alaska Division of Geological & Geophysical Surveys Ingram Creek
Alaska Division of Geological & Geophysical Surveys Kickstep Mountain
Alaska Division of Geological & Geophysical Surveys Lynx Creek
Alaska Division of Geological & Geophysical Surveys Lyon Creek
Alaska Division of Geological & Geophysical Surveys Petes Creek
Alaska Division of Geological & Geophysical Surveys Spokane Creek
Alaska Division of Geological & Geophysical Surveys Taylor Creek
Alaska Division of Geological & Geophysical Surveys Tincan Creek
Alaska Division of Geological & Geophysical Surveys Tincan Peak
Alaska Division of Geological & Geophysical Surveys Turnagain Arm
Alaska Division of Geological & Geophysical Surveys Turnagain Pass
Alaska Division of Geological & Geophysical Surveys Wolverine Creek

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 U.S. Geological Surveys and Alaska Department of Natural Resources, Division of Geological & Geophysical Surveys. We thank Clearwater Air for their aviation expertise and contribution to these data products., Wikstrom Jones, Katreen Wolken, G.J. Daanen, R.P. Herbst, A.M.

Support Roles

Data Steward

CC ID: 1184344
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: 1184343
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: 1184345
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: 1184346
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: 1298521
W° Bound: -149.331846
E° Bound: -149.022184
N° Bound: 60.866217
S° Bound: 60.707115

Extent Group 1 / Time Frame 1

CC ID: 1298520
Time Frame Type: Discrete
Start: 2018-09-02

Spatial Information

Spatial Representation

Representations Used

Grid: Yes

Reference Systems

Reference System 1

CC ID: 1298518

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: 1298517

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: 1184347
Start Date: 2022-09-08
End Date: Present
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=9583/details/9583
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2022 - Present)
File Name: Customized Download
Description:

Create custom data files by choosing data area, product type, map projection, file format, datum, etc. A new metadata will be produced to reflect your request using this record as a base. Change to an orthometric vertical datum is one of the many options.

File Type (Deprecated): Zip
Compression: Zip

Distribution 2

CC ID: 1184348
Start Date: 2022-09-08
End Date: Present
Download URL: https://noaa-nos-coastal-lidar-pds.s3.us-east-1.amazonaws.com/dem/AK_Turnagain_DEM_2018_9583/index.html
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2022 - Present)
File Name: Bulk Download
Description:

Bulk download of data files in GeoTiff format, UTM Zone 6 NAD83 (2011) (EPSG: 6335), meters coordinates and orthometric heights in meters (EPSG: 5703).

File Type (Deprecated): GeoTIFF
Distribution Format: GeoTIFF

URLs

URL 1

CC ID: 1184349
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 2

CC ID: 1184350
URL: https://dggs.alaska.gov/webpubs/dggs/rdf/text/rdf2020_016.pdf
Name: Lidar Report
URL Type:
Online Resource
File Resource Format: pdf
Description:

Link to the lidar report.

URL 3

CC ID: 1184351
URL: https://coast.noaa.gov/lidar/viewer/v/noaapotree.html?m=9582&g=geoid12b
Name: Potree 3D View
URL Type:
Online Resource
Description:

Link to view the point cloud (using the Entwine Point Tile (EPT) format) in the 3D Potree viewer.

URL 4

CC ID: 1184352
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/entwine/geoid12b/9582/ept.json
Name: Entwine Point Tiles (EPT)
URL Type:
Online Resource
File Resource Format: json
Description:

Entwine Point Tile (EPT) is a simple and flexible octree-based storage format for point cloud data. The data is organized in such a way that the data can be reasonably streamed over the internet, pulling only the points you need. EPT files can be queried to return a subset of the points that give you a representation of the area. As you zoom further in, you are requesting higher and higher densities. A dataset in EPT will contain a lot of files, however, the ept.json file describes all the rest. The EPT file can be used in Potree and QGIS to view the point cloud.

URL 5

CC ID: 1184353
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid12b/9582/supplemental/ak2018_turnagain_m9582.kmz
Name: Browse Graphic
URL Type:
Browse Graphic
File Resource Format: kmz
Description:

This graphic displays the footprint for this lidar data set.

Data Quality

Horizontal Positional Accuracy:

Horizontal accuracy was not measured for this collection.

Vertical Positional Accuracy:

The elevation values of 62 ground control points were compared with the elevation values of the lidar points classified as ground points. The average vertical offset was corrected with a z-transformation. Fifteen check points were used to determine the final accuracy of the z-transformed lidar point cloud. The lidar point cloud had a vertical offset of +2.2 cm (root mean squared error [RMSE] 3.6 cm) compared to ground control, therefore a vertical transformation of -2.2 cm was applied to the lidar point cloud. Relative accuracy for this dataset was evaluated as the interswath overlap consistency and was measured at 1.2 cm RMSE.

The final accuracy assessment showed a mean vertical offset of -0.3 cm and RMSE of 3.3 cm.

Completeness Report:

This data release is complete and there is no over collect, except for the aircraft turns that were eliminated from the dataset. There are a few areas where data coverage is limited due to laser range exceedance, which is related to the slow response of the fixed wing aircraft to the fast elevation change along the flight path. All low points and air points were eliminated from the dataset.

Conceptual Consistency:

Relative accuracy for this dataset was evaluated as the interswath overlap consistency and was measured at 1.2 cm RMSE.

Data Management

Have Resources for Management of these Data Been Identified?: Yes
Approximate Percentage of Budget for these Data Devoted to Data Management: Unknown
Do these Data Comply with the Data Access Directive?: Yes
Actual or Planned Long-Term Data Archive Location: NCEI-CO
How Will the Data Be Protected from Accidental or Malicious Modification or Deletion Prior to Receipt by the Archive?:

Data is backed up to tape and to cloud storage.

Lineage

Lineage Statement:

The data were collected for the Alaska Division of Geological and Geophysical Surveys (DGGS) and made available on the AK DGGS Elevation Portal (https://elevation.alaska.gov/). The NOAA Office for Coastal Management (OCM) downloaded the data from this site to make the data available for custom downloads from the NOAA Digital Coast Data Access Viewer and for bulk downloads from https.

Sources

Alaska Division of Geological and Geophysical Surveys (AK DGGS)

CC ID: 1298512
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: 1298513
Description:

Airborne survey - This lidar survey was flown at an average elevation of 200 m above ground level and a ground speed of approximately 40 meters per second with a fixed-wing Cessna 180. Elevation data were acquired with a Riegl VUX1-LR laser scanner integrated with a GNSS and Northrop Grumman IMU system. The integration was designed by Phoenix LiDAR systems. Lidar data were acquired at a pulse rate ranging from 50,000 pulses per second in the alpine areas to 400,000 pulses per second over forested areas, a scan rate of 200 revolutions per second, and a scan angle range of 80-280 degrees. The accompanying report provides additional detail regarding flight conditions.

Process Date/Time: 2018-09-02 00:00:00

Process Step 2

CC ID: 1298514
Description:

Ground survey - Ground control and check points were collected on September 2, 2018. A Trimble R7 GNSS receiver with Zephyr-2 antenna was deployed near the center of the study area and provided a base station occupation and real-time kinematic (RTK) corrections to points surveyed with a rover Trimble R8-4 GNSS receiver (internal antenna). 78 total 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 a paved road surface.

Process Date/Time: 2018-09-02 00:00:00

Process Step 3

CC ID: 1298515
Description:

Lidar dataset processing - Raw data were processed using Terrasolid software to produce integrated files for navigation correction and a point cloud for calibration. The navigation was corrected using Inertial Explorer software, where the GNSS and IMU data are integrated to establish correct flight path and orientation of the lidar sensor. Internal consistency of the dataset was improved by calibrating the point cloud data using global, flight line, and fluctuation (within individual flightlines) tielines in Terrasolid software. The point cloud was classified for ground points as well as low, medium, and high vegetation (0.01-0.5 m, 0.5-3 m, and 3-60 m heights above the ground, respectively, in accordance with ASPRS lidar classification codes). Some manual processing was required to eliminate erratically placed points and misclassified ground points. All low points and air points were eliminated from the dataset. A LAS dataset was created in ArcMAP, from which a 50 cm DTM, DSM, and intensity image were produced. The DTM was derived from elevation values of ground-classified points only, and built using the binning technique of minimum elevation and linear void fill. The DSM was derived from elevation values from first returns from all point classes, and built using the binning technique of average elevation values and linear void fill. The intensity image was derived from intensity values of first return points.

Process Date/Time: 2019-01-01 00:00:00

Process Step 4

CC ID: 1298516
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 files were at a 0.5 meter grid spacing.

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 file.

2. Copied the files to https.

Process Date/Time: 2022-09-15 00:00:00
Process Contact: Office for Coastal Management (OCM)

Related Items

Item Type Relationship Type Title
Data Set (DS) Cross Reference 2018 AK DGGS Lidar: Turnagain Pass, Alaska

Catalog Details

Catalog Item ID: 67892
GUID: gov.noaa.nmfs.inport:67892
Metadata Record Created By: Rebecca Mataosky
Metadata Record Created: 2022-09-15 18:37+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: 2022-09-08
Metadata Review Frequency: 1 Year
Metadata Next Review Date: 2023-09-08