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Short Citation:
OCM Partners, 2023: 2019 AK DGGS Lidar DEM: Kotlik, AK, https://www.fisheries.noaa.gov/inport/item/68000.

Item Identification

Title: 2019 AK DGGS Lidar DEM: Kotlik, AK
Short Name: ak2019_kotlik_dem_m9607_metadata
Status: Completed
Creation Date: 2019
Publication Date: 2020
Abstract:

The Alaska Division of Geological & Geophysical Surveys (DGGS) used aerial lidar to produce a digital terrain model (DTM), surface model (DSM), and intensity model for the area surrounding the community of Kotlik, Alaska. Detailed bare earth elevation data for the Kotlik area support and inform potential infrastructure development and provide critical information required to assess geomorphic activity. Airborne data were collected on August 17, 2019, and subsequently processed in Terrasolid and ArcGIS. Ground control was collected between August 20-22, 2019, by the Alaska Division of Mining, Land, and Water. 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/10.14509/30561).

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.

Purpose:

Detailed bare earth elevation data for the Kotlik area support and inform potential infrastructure development and provide critical information required to assess geomorphic activity. 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 24.8 cm and the average density was 16.25 pts/m^2. Elevation surfaces interpolated from areas with a point density of fewer than 4pts/m2 were classified as nodata.

>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 0.5 meters. 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 0.5 meters. 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 0.5 meters. 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 0.5 meters. 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 Apoon
Alaska Division of Geological & Geophysical Surveys Apoon Pass
Alaska Division of Geological & Geophysical Surveys Chaniliut
Alaska Division of Geological & Geophysical Surveys Kaelhuk Pass
Alaska Division of Geological & Geophysical Surveys Kotlik
Alaska Division of Geological & Geophysical Surveys Kotlik River
Alaska Division of Geological & Geophysical Surveys Kvichvauk Pass
Alaska Division of Geological & Geophysical Surveys Little Kotlik River
Alaska Division of Geological & Geophysical Surveys Nelutahalik Creek
Alaska Division of Geological & Geophysical Surveys Norton Sound
Alaska Division of Geological & Geophysical Surveys Pastol Bay
Alaska Division of Geological & Geophysical Surveys Pastoliak River
Alaska Division of Geological & Geophysical Surveys Pastolik River
Alaska Division of Geological & Geophysical Surveys Tatlalinguk Pass

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 express or implied warranties (including warranties of merchantability and fitness) with respect to the character, function, or capabilities of the electronic services 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, any failure thereof, or otherwise, and 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 were paid for by the State of Alaska and collected and processed by DGGS. A ground survey was conducted for quality control by the Alaska Division of Mining, Land, and Water, and supported by the Native Village of Bill Moore's Slough and the Native Village of Kotlik., Herbst, A.M. Daanen, R.D.

Support Roles

Data Steward

CC ID: 1186899
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: 1186898
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: 1186900
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: 1186901
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: 1186904
W° Bound: -163.659031
E° Bound: -163.005119
N° Bound: 63.111833
S° Bound: 62.986807

Extent Group 1 / Time Frame 1

CC ID: 1186903
Time Frame Type: Discrete
Start: 2019-08-17

Spatial Information

Spatial Representation

Representations Used

Grid: Yes

Reference Systems

Reference System 1

CC ID: 1186953

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: 1186994

Coordinate Reference System

CRS Type: Projected
EPSG Code: EPSG:6332
EPSG Name: NAD83(2011) / UTM zone 3N
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: 1186906
Start Date: 2022-10-07
End Date: Present
Download URL: https://chs.coast.noaa.gov/htdata/raster5/elevation/AK_Kotlik_DEM_2019_9607
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

Distribution 2

CC ID: 1186905
Start Date: 2022-10-07
End Date: Present
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=9607/details/9607
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

URLs

URL 1

CC ID: 1186896
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: 1186897
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: 1186949
URL: https://dggs.alaska.gov/webpubs/dggs/rdf/text/rdf2020_015.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.

URL 4

CC ID: 1186950
URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=9606/details/9606
Name: Custom Point Download
URL Type:
Online Resource
File Resource Format: Zip
Description:

Link to custom download, from the Data Access Viewer (DAV), the lidar point data from which these raster Digital Elevation Model (DEM) data were created.

URL 5

CC ID: 1187142
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid12b/9606/supplemental/ak2019_kotlik_m9606.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:

Forty-two bare earth checkpoints 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 8.2 cm. Using the same approach, fifty-two vegetated points were used to determine the vegetated vertical accuracy (VVA) of the point cloud ground class. Project VVA was evaluated at 25.2 cm RMSE, with an average elevation difference of +21.2 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.

Conceptual Consistency:

The data quality is consistent throughout the survey. The accompanying report provides additional detail regarding tests used to determine data fidelity.

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: 1186954
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: 1186892
Description:

Airborne survey - DGGS operates a Riegl 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 between 200,000 and 400,000 points per second at a scan rate between 80 and 150 lines per second. This survey was flown with an average elevation of 400 m above ground level and a ground speed of approximately 40 m/s with a fixed-wing aircraft configuration, using a Cessna 185 aircraft. The scan angle was set from 55 to 305 degrees. The total area surveyed was approximately 15 km2. The accompanying report provides additional detail regarding flight conditions.

Process Date/Time: 2019-08-17 00:00:00

Process Step 2

CC ID: 1186893
Description:

Ground survey - The Alaska Division of Mining, Land, and Water acquired surveyed ground control August 20-22, 2019 in an approximate 2-mile radius around the town of Kotlik. Ninety-four points were collected, including 42 bare earth, 18 forested, 33 low-vegetation, and 1 urban surface points.

Process Date/Time: 2019-08-22 00:00:00

Process Step 3

CC ID: 1186894
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. IMU and GPS data were 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 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) 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 hydroflattened raster, incorporating hydrography polygons from the AK SDMI IFSAR dataset. The DSM was likewise interpolated from only the first returns for all classes. 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: 1186951
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 3N NAD83 (2011), meters coordinates and NAVD88 (Geoid12B) elevations in meters. The bare earth raster file was at a 0.5 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: 6332 and Vertical EPSG: 5703) to the GeoTiff formatted file.

2. Copied the file to https.

Process Date/Time: 2022-10-07 00:00:00
Process Contact: Office for Coastal Management (OCM)

Related Items

Item Type Relationship Type Title
Data Set (DS) Cross Reference 2019 AK DGGS Lidar: Kotlik, Alaska

Catalog Details

Catalog Item ID: 68000
GUID: gov.noaa.nmfs.inport:68000
Metadata Record Created By: Rebecca Mataosky
Metadata Record Created: 2022-10-07 19:59+0000
Metadata Record Last Modified By: SysAdmin InPortAdmin
Metadata Record Last Modified: 2023-10-17 16:12+0000
Metadata Record Published: 2022-10-11
Owner Org: OCMP
Metadata Publication Status: Published Externally
Do Not Publish?: N
Metadata Last Review Date: 2022-10-11
Metadata Review Frequency: 1 Year
Metadata Next Review Date: 2023-10-11