gov.noaa.nmfs.inport:52874
eng
UTF8
dataset
Elevation
OCM Partners
resourceProvider
NOAA Office for Coastal Management
(843) 740-1202
2234 South Hobson Ave
Charleston
SC
29405-2413
coastal.info@noaa.gov
https://coast.noaa.gov
WWW:LINK-1.0-http--link
NOAA Office for Coastal Management Website
NOAA Office for Coastal Management Home Page
information
pointOfContact
2024-02-29T00:00:00
ISO 19115-2 Geographic Information - Metadata Part 2 Extensions for imagery and gridded data
ISO 19115-2:2009(E)
EPSG::6360
2016 DOWL Lidar DEM: Chena River Lakes, Alaska
ak2016_chena_dem_m8541_metadata
2017
creation
publication
NOAA/NMFS/EDM
52874
https://www.fisheries.noaa.gov/inport/item/52874
WWW:LINK-1.0-http--link
Full Metadata Record
View the complete metadata record on InPort for more information about this dataset.
information
https://coast.noaa.gov/
WWW:LINK-1.0-http--link
NOAA's Office for Coastal Management (OCM) website
Information on the NOAA Office for Coastal Management (OCM)
download
https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid12b/8540/supplemental/ak2016_chena_m8540_lidar_report.pdf
WWW:LINK-1.0-http--link
Dataset report
Link to data set report.
download
https://coast.noaa.gov/dataviewer/
WWW:LINK-1.0-http--link
NOAA's Office for Coastal Management (OCM) Data Access Viewer (DAV)
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.
download
This metadata record was created by the NOAA Office for Coastal Management (OCM) because no metadata record was available for the data. Information to create this record was taken from the Quantum Spatial Chena River Lakes LiDAR Technical Data Report. There is a link to this report in the URL section of this metadata record. The report indicates that the data are in Alaska State Plane Zone 3, NAD83 (NSRS2007), US survey feet and in NAVD88 (GEOID06) with vertical units in US survey feet.
The NOAA Office for Coastal Management (OCM) downloaded the gridded Digital Elevation Model (DEM) data from the AK DGGS site (https://elevation.alaska.gov/) and processed the data to be available on the Digital Coast Data Access Viewer (DAV).
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.
In early 2016, Quantum Spatial (QSI) was contracted by DOWL, Inc. to collect Light Detection and Ranging (LiDAR) data in the spring of 2016 for the Chena River Lakes site in Alaska.
Data were collected to aid DOWL, Inc. in assessing the topographic and geophysical properties of the study area and to support engineering and mapping endeavors.
DOWL, Inc.
completed
NOAA Office for Coastal Management
(843) 740-1202
2234 South Hobson Ave
Charleston
SC
29405-2413
coastal.info@noaa.gov
https://coast.noaa.gov
WWW:LINK-1.0-http--link
NOAA Office for Coastal Management Website
NOAA Office for Coastal Management Home Page
information
pointOfContact
NOAA Office for Coastal Management
(843) 740-1202
2234 South Hobson Ave
Charleston
SC
29405-2413
coastal.info@noaa.gov
https://coast.noaa.gov
WWW:LINK-1.0-http--link
NOAA Office for Coastal Management Website
NOAA Office for Coastal Management Home Page
information
custodian
unknown
https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid12b/8540/supplemental/ak2016_chena_m8540.kmz
This graphic displays the footprint for this lidar data set.
KML
EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION
EARTH SCIENCE > OCEANS > COASTAL PROCESSES > COASTAL ELEVATION
theme
Global Change Master Directory (GCMD) Science Keywords
17.0
CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA > ALASKA
VERTICAL LOCATION > LAND SURFACE
place
Global Change Master Directory (GCMD) Location Keywords
17.0
LIDAR > Light Detection and Ranging
instrument
Global Change Master Directory (GCMD) Instrument Keywords
17.2
Airplane > Airplane
DEM > Digital Elevation Model
platform
Global Change Master Directory (GCMD) Platform Keywords
17.2
DEM
erosion
theme
2016
May
temporal
DEMs - partner (no harvest)
project
InPort
otherRestrictions
Cite As: OCM Partners, [Date of Access]: 2016 DOWL Lidar DEM: Chena River Lakes, Alaska [Data Date Range], https://www.fisheries.noaa.gov/inport/item/52874.
NOAA provides no warranty, nor accepts any liability occurring from any incomplete, incorrect, or misleading data, or from any incorrect, incomplete, or misleading use of the data. It is the responsibility of the user to determine whether or not the data is suitable for the intended purpose.
otherRestrictions
Access Constraints: None
otherRestrictions
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.
otherRestrictions
Distribution Liability: Any conclusions drawn from the analysis of this information are not the responsibility of NOAA, the Office for Coastal Management or its partners.
unclassified
NOAA Data Management Plan (DMP)
NOAA/NMFS/EDM
52874
https://www.fisheries.noaa.gov/inportserve/waf/noaa/nos/ocmp/dmp/pdf/52874.pdf
WWW:LINK-1.0-http--link
NOAA Data Management Plan (DMP)
NOAA Data Management Plan for this record on InPort.
information
crossReference
eng; US
elevation
-147.321
-147.04
64.7
64.838
| Currentness: Ground Condition
2016-05-01
Zip
Zip
GeoTIFF
NOAA Office for Coastal Management
(843) 740-1202
2234 South Hobson Ave
Charleston
SC
29405-2413
coastal.info@noaa.gov
https://coast.noaa.gov
WWW:LINK-1.0-http--link
NOAA Office for Coastal Management Website
NOAA Office for Coastal Management Home Page
information
distributor
https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=8541
WWW:LINK-1.0-http--link
Customized Download
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.
download
https://noaa-nos-coastal-lidar-pds.s3.us-east-1.amazonaws.com/dem/AK_Chena_DEM_2016_8541/index.html
WWW:LINK-1.0-http--link
Bulk Download
Bulk download of data files in the original coordinate system.
download
dataset
Vertical Positional Accuracy
Absolute accuracy was assessed using Fundamental Vertical Accuracy (FVA) reporting designed to meet guidelines presented in the FGDC National Standard for Spatial Data Accuracy 2. FVA compares known ground quality assurance point data collected on open, bare earth surfaces with level slope (<20 degrees) to the triangulated surface generated by the LiDAR points. FVA is a measure of the accuracy of LiDAR point data in open areas where the LiDAR system has a high probability of measuring the ground surface and is evaluated at the 95% confidence interval (1.96 * RMSE). The mean and standard deviation of divergence of the ground surface model from quality assurance point coordinates are also considered during accuracy assessment. These statistics assume the error for x, y, and z is normally distributed, and therefore the skew and kurtosis of distributions are also considered when evaluating error statistics. For the Chena River Lakes survey, 80 quality assurance points were used for Fundamental Vertical Accuracy (FVA) calculations which resulted in an FVA value of 0.188 feet (0.057 meters) .
Vertical accuracy was also assessed using Supplemental Vertical Accuracy (SVA) and Consolidated Vertical Accuracy (CVA) reporting. SVA compares known ground check point data within individual land cover class categories to the triangulated ground surface generated by the ground classified LiDAR points while CVA compares known ground check points within all land cover classes. SVA and CVA are evaluated at the 95th percentile.
SVA
Brush - 0.452 ft (0.138 m)
Gravel - 0.152 ft (0.046 m)
Forest - 0.337 ft (0.102 m)
CVA - 0.231 ft (0.070 m)
Completeness Report
Complete
Planning
In preparation for data collection, QSI reviewed the project area and developed a specialized flight plan to ensure complete coverage of the Chena River Lakes LiDAR study area at the target point density of ≥12.0 points/m2 (1.11 points/ft2). Acquisition parameters including orientation relative to terrain, flight altitude, pulse rate, scan angle, and ground speed were adapted to optimize flight paths and flight times while meeting all contract specifications.
Factors such as satellite constellation availability and weather windows must be considered during the planning stage. Any weather hazards or conditions affecting the flights were continuously monitored due to their potential impact on the daily success of airborne and ground operations. In addition, logistical considerations including private property access and potential air space restrictions were reviewed.
Acquisition
The LiDAR survey was accomplished using a Leica ALS80 system mounted in a Cessna Caravan. Table 3 in the technical report summarizes the settings used to yield an average pulse density of greater than or equal to 12 pulses/m2 over the Chena River Lakes project area. The Leica ALS80 laser system can record unlimited range measurements (returns) per pulse. It is not uncommon for some types of surfaces (e.g., dense vegetation or water) to return fewer pulses to the LiDAR sensor than the laser originally emitted. The discrepancy between first return and overall delivered density will vary depending on terrain, land cover, and the prevalence of water bodies. All discernible laser returns were processed for the output dataset.
All areas were surveyed with an opposing flight line side-lap of ≥60% (≥100% overlap) in order to reduce laser shadowing and increase surface laser painting. To accurately solve for laser point position (geographic coordinates x, y and z), the positional coordinates of the airborne sensor and the attitude of the aircraft were recorded continuously throughout the LiDAR data collection mission. Position of the aircraft was measured twice per second (2 Hz) by an onboard differential GPS unit, and aircraft attitude was measured 200 times per second (200 Hz) as pitch, roll and yaw (heading) from an onboard inertial measurement unit (IMU). To allow for post-processing correction and calibration, aircraft and sensor position and attitude data are indexed by GPS time.
2016-05-01T00:00:00
Ground Control
Ground control surveys, including monumentation and the collection of ground survey points (GSPs), were conducted by DOWL to support the airborne acquisition. Ground control data were used to geospatially correct the aircraft positional coordinate data and to perform quality assurance checks on final LiDAR data.
QSI used static GNSS data provided by DOWL from base stations set up over three monument locations for the Chena River Lakes LiDAR project All survey data were reviewed by QSI staff upon receipt, and monument positions were verified by processing static GNSS data against nearby Continuously Operating Reference Stations (CORS) using the Online Positioning User Service (OPUS1).
Ground survey points were collected by DOWL using real time kinematic survey techniques and supplied to QSI for LiDAR calibration.
In addition to ground survey points, land cover class control points were collected and provided by DOWL throughout the study area. Individual accuracies were calculated for each land cover type to assess confidence in the LiDAR-derived ground models across land cover classes.
Lidar Processing
Upon completion of data acquisition, QSI processing staff initiated a suite of automated and manual techniques to process the data into the requested deliverables. Processing tasks included GPS control computations, smoothed best estimate trajectory (SBET) calculations, kinematic corrections, calculation of laser point position, sensor and data calibration for optimal relative and absolute accuracy, and LiDAR point classification. Processing methodologies were tailored for the landscape.
Resolve kinematic corrections for aircraft position data using kinematic aircraft GPS and static ground GPS data. Develop a smoothed best estimate of trajectory (SBET) file that blends post-processed aircraft position with sensor head position and attitude recorded throughout the survey.
Calculate laser point position by associating SBET position to each laser point return time, scan angle, intensity, etc. Create raw laser point cloud data for the entire survey in *.las (ASPRS v. 1.2) format. Convert data to orthometric elevations by applying a geoid06 correction
Import raw laser points into manageable blocks to perform manual relative accuracy calibration and filter erroneous points. Classify ground points for individual flight lines.
Using ground classified points per each flight line, test the relative accuracy. Perform automated line-to-line calibrations for system attitude parameters (pitch, roll, heading), mirror flex (scale) and GPS/IMU drift. Calculate calibrations on ground classified points from paired flight lines and apply results to all points in a flight line. Use every flight line for relative accuracy calibration.
Classify resulting data to ground and other client designated ASPRS classifications. Assess statistical absolute accuracy via direct comparisons of ground classified points to ground control survey data.
Generate bare earth models as triangulated surfaces. Generate highest hit models as a surface expression of all classified points. Export all surface models as ESRI GRIDs at a 3.0 foot pixel resolution.
Correct intensity values for variability and export intensity images as GeoTIFFs at a 1.5 foot pixel resolution.
The NOAA Office for Coastal Management (OCM) downloaded 507 DEM files from the Alaska Division of Geological and Geophysical Surveys data Portal (https://elevation.alaska.gov/). The report indicates that the data are in Alaska State Plane Zone 3, NAD83 (NSRS2007), US survey feet and in NAVD88 (GEOID06) with vertical units in US survey feet. The bare earth raster files are at a 3 ft grid spacing.
OCM converted the files to Cloud Optimized GeoTiffs and set the vertical georeferencing using GeoTiff 1.1 format.
2023-06-26T00:00:00
Office for Coastal Management
processor