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

Summary

Short Citation
OCM Partners, 2024: 2018 AK DGGS Lidar DEM: Chilkat Ridge, Alaska, https://www.fisheries.noaa.gov/inport/item/68619.
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) over ridgelines along the Chilkat River just north of Haines, Alaska. The lidar and Global Navigation Satellite System (GNSS) data were collected on November 15-16, 2018, and processed using Terrasolid. This data collection is being released as a Raw Data File with an open end-user license. The complete report and digital data are available from the DGGS website: http://doi.org/10.14509/30224.

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

https://elevation.alaska.gov/

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be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions.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

-135.97071° W, -135.640466° E, 59.414268° N, 59.236685° S

Time Frame 1
2018-11-15 - 2018-11-16

Item Identification

Title: 2018 AK DGGS Lidar DEM: Chilkat Ridge, Alaska
Short Name: ak2018_chilkat_m9672_metadata
Status: Completed
Creation Date: 2018-01-01
Publication Date: 2019
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) over ridgelines along the Chilkat River just north of Haines, Alaska. The lidar and Global Navigation Satellite System (GNSS) data were collected on November 15-16, 2018, and processed using Terrasolid. This data collection is being released as a Raw Data File with an open end-user license. The complete report and digital data are available from the DGGS website: http://doi.org/10.14509/30224.

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

https://elevation.alaska.gov/

This 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:

This dataset includes point cloud data, a 32-bit digital terrain model, and an intensity image covering a study area near the Chilkat Ridge region of southeast Alaska. The data release is one of a series of Alaska Division of Geological & Geophysical Surveys (DGGS) publications to present elevation data. The goal is to provide information for the Alaska Division of Forestry on the ground conditions and tree cover on Chilkat Ridge.

Supplemental Information:

>point_cloud_data: Classified (ASPRS standard) lidar values for all returns; File format: LAS 1.4.

>dtm: DTMs represent surface elevations of ground surfaces, excluding vegetation, bridges, buildings, etc. The DTM is a single-band, 1 meter, 32-bit float GeoTIFF file, with a ground sample distance (GSD) of 15 cm on the ground and 60 cm below dense vegetation. No Data value is set to -3.40282306074e+038.

>dsm: A 2-meter DSM raster was created from the first returns of the laser point cloud. The No Data value is set to -3.40282306074e+038.

>intensity_image: A grayscale image that displays 0-255 grayscale values according to relative reflectivity. The laser intensity image is provided as a 1-meter raster.

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 Anman Creek
Alaska Division of Geological & Geophysical Surveys Birch Island
Alaska Division of Geological & Geophysical Surveys Chilkat
Alaska Division of Geological & Geophysical Surveys Chilkat Lake
Alaska Division of Geological & Geophysical Surveys Chilkat River
Alaska Division of Geological & Geophysical Surveys Chilkat River State Critical Habitat Area
Alaska Division of Geological & Geophysical Surveys Dalton Trail
Alaska Division of Geological & Geophysical Surveys Juneau Mining District
Alaska Division of Geological & Geophysical Surveys Kicking Horse River
Alaska Division of Geological & Geophysical Surveys Klehini River
Alaska Division of Geological & Geophysical Surveys Kohklux
Alaska Division of Geological & Geophysical Surveys Porcupine Creek Mining District
Alaska Division of Geological & Geophysical Surveys Southeast Alaska
Alaska Division of Geological & Geophysical Surveys Takhin River
Alaska Division of Geological & Geophysical Surveys Tsirku River

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 Alaska Division of Forestry. We thank Clearwater Air from Anchorage for their aviation expertise and contribution to these data products., Daanen, R.D. Wikstrom Jones, Katreen Wolken, G.J. Herbst, A.M.

Support Roles

Data Steward

CC ID: 1195479
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: 1195478
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: 1195480
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: 1195481
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: 1298919
W° Bound: -135.97071
E° Bound: -135.640466
N° Bound: 59.414268
S° Bound: 59.236685

Extent Group 1 / Time Frame 1

CC ID: 1298918
Time Frame Type: Range
Start: 2018-11-15
End: 2018-11-16

Spatial Information

Spatial Representation

Representations Used

Grid: Yes

Reference Systems

Reference System 1

CC ID: 1298916

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: 1298915

Coordinate Reference System

CRS Type: Projected
EPSG Code: EPSG:6337
EPSG Name: NAD83(2011) / UTM zone 8N
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: 1195485
Start Date: 2022-11-29
End Date: Present
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=9672/details/9672
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: 1195486
Start Date: 2022-11-29
End Date: Present
Download URL: https://noaa-nos-coastal-lidar-pds.s3.us-east-1.amazonaws.com/dem/AK_Chilkat_DEM_2018_9672/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: 1195476
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: 1195477
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: 1195532
URL: https://dggs.alaska.gov/webpubs/dggs/rdf/text/rdf2019_007.pdf
Name: Lidar Report
URL Type:
Online Resource
File Resource Format: pdf
Description:

This lidar report provides accompanying information about the collection and processing of this lidar data set.

Data Quality

Horizontal Positional Accuracy:

Horizontal accuracy was not evaluated for this project.

Vertical Positional Accuracy:

The Root Mean Square Error of the final data layers for the bare earth elevation between the checkpoints and lidar ground points is 8.5 centimeters.

Completeness Report:

The total area surveyed was approximately 224 km2. 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 the slow response of the fixed wing aircraft the fast elevation changes along the flight path, e.g., canyons. Void areas for lakes and ponds, which were hydroflattened in the elevation models, were delineated as null data in the intensity rasters.

Conceptual Consistency:

To evaluate data consistency, ground checkpoints were collected (November 15, 2018) as RTK-GNSS points with a Trimble R8 GNSS receiver. A Trimble R7 GNSS receiver with Zephyr-2 antenna was deployed near the center of the study area and was used as horizontal and vertical control for checkpoint baseline corrections. The checkpoints were compared with the DTM. The comparison showed a 7.1 cm average magnitude difference between the checkpoints and the DTM. The checkpoint differences had a Root Mean Square Error of 8.5 cm and a standard deviation of 8.6 cm.

Lineage

Sources

Alaska Division of Geological and Geophysical Surveys (AK DGGS)

CC ID: 1298906
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: 1298907
Description:

Lidar data acquisition - DGGS operates a Riegle VUX1-LR lidar integrated with a GNSS and Northrop Grumman IMU system. The integration 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 at a scan rate of 400,000 points per second and a scan rate of 200 revolutions per second. The average pulse spacing was 15 cm and the average point density was 40 points per square meter. This survey was flown with an average elevation of 200 m above ground level and a ground speed of approximately 40 m/s with a fixed-wing aircraft configuration, using Cessna 185. The scan angle was set from 55 to 305. Ground Control points were collected using a Trimble system consisting of a Trimble R7 base station and an R8 rover system.

Process Date/Time: 2018-01-01 00:00:00

Process Step 2

CC ID: 1298908
Description:

Raw lidar data 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 GNNS and IMU data are integrated to establish the correct flight path and orientation of the lidar sensor.

Process Date/Time: 2018-01-01 00:00:00

Process Step 3

CC ID: 1298909
Description:

Point cloud data calibration - Internal lidar point cloud data were calibrated using Terrasolid software. The initial accuracy of the point cloud was 8.346 cm. After calibration, the point cloud had an average magnitude accuracy of 6.914 cm.

Process Date/Time: 2018-01-01 00:00:00

Process Step 4

CC ID: 1298910
Description:

Point cloud data classification - The point cloud is classified for ground points as well as low, medium, and high vegetation (0.01-0.3 m, 0.3-5 m, and 5-60 m heights above the ground, respectively). Some manual processing was required to eliminate fog and misclassified ground points. All low points and air points are eliminated from the dataset. Lastly, the DSM and DTM were hydroflattened to mean surrounding elevation for all lakes and ponds.

Process Date/Time: 2018-01-01 00:00:00

Process Step 5

CC ID: 1298911
Description:

Digital terrain model - The ground points from the final point cloud were used to build the digital terrain model in ArcGIS. The point cloud was loaded as a las dataset and filtered for ground points. The remaining points were used in a las dataset-to-raster conversion tool. Rasters, with a ground pixel resolution of 1 meter, were derived from mean values from a 2-meter sampling distance. The DTM was hydroflattened to mean surrounding elevation for all lakes and ponds.

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

Process Step 6

CC ID: 1298912
Description:

Digital surface model - The digital surface model was created from the first returns in the point cloud. Due to a large number of points in vegetation, we used a binning method with natural neighbor gap-filling. The 1 m bins did not gap-fill correctly in the entire dataset, however, so we opted to store the DSM in a 2-m-resolution raster. The DSM was hydroflattened to mean surrounding elevation for all lakes and ponds.

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

Process Step 7

CC ID: 1298913
Description:

Intensity image - The intensity raster was generated using the ground points. The raster resolution is 1-meter.

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

Process Step 8

CC ID: 1298914
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 8N NAD83 (2011), meters coordinates and NAVD88 (Geoid12B) elevations in meters. The bare earth raster file was at a 1 meter grid spacing.

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

1. Used an internal script to assign the EPSG codes (Horizontal EPSG: 6337 and Vertical EPSG: 5703) to the GeoTiff formatted file.

2. Copied the files to https.

Process Date/Time: 2022-11-29 00:00:00
Process Contact: Office for Coastal Management (OCM)

Catalog Details

Catalog Item ID: 68619
GUID: gov.noaa.nmfs.inport:68619
Metadata Record Created By: Rebecca Mataosky
Metadata Record Created: 2022-11-29 18:53+0000
Metadata Record Last Modified By: Kirk Waters
Metadata Record Last Modified: 2024-01-10 19:28+0000
Metadata Record Published: 2024-01-10
Owner Org: OCMP
Metadata Publication Status: Published Externally
Do Not Publish?: N
Metadata Last Review Date: 2022-11-30
Metadata Review Frequency: 1 Year
Metadata Next Review Date: 2023-11-30