2019 USACE NCMP Topobathy Lidar DEM: Alaska
Data Set (DS) | OCM Partners (OCMP)GUID: gov.noaa.nmfs.inport:59419 | Updated: January 10, 2024 | Published / External
Summary
Short Citation
OCM Partners, 2024: 2019 USACE NCMP Topobathy Lidar DEM: Alaska, https://www.fisheries.noaa.gov/inport/item/59419.
Full Citation Examples
These files contain rasterized topobathy lidar elevations generated from data collected by the Coastal Zone Mapping and Imaging Lidar (CZMIL) system. CZMIL integrates a lidar sensor with simultaneous topographic and bathymetric capabilities, a digital camera and a hyperspectral imager on a single remote sensing platform for use in coastal mapping and charting activities. Native lidar data is not generally in a format accessible to most Geographic Information Systems (GIS). Specialized in-house and commercial software packages are used to process the native lidar data into 3-dimensional positions that can be imported into GIS software for visualization and further analysis. Horizontal positions, provided in decimal degrees of latitude and longitude, are referenced to the North American Datum of 1983 National Adjustment of 2011 (NAD83 (2011)). Vertical positions are referenced to the NAD83 (2011) ellipsoid and provided in meters. The National Geodetic Survey's (NGS) GEOID12B model is used to transform the vertical positions from ellipsoid to orthometric heights referenced to the North American Vertical Datum of 1988 (NAVD88). The 3-D position data are sub-divided into a series of LAS files, which are tiled into 1-km by 1-km boxes defined by the Military Grid Reference System. The LAS file index is provided by the shape files, "MGRS_1km_04V.shp ", and the numbers used to identify files are in the "Box" field of the shape file. The data file naming convention is based on the year, effort, area, "Box" number and data product type. An example file name is "2019_NCMP_AK_04VDR0987_BareEarth_1mGrid.tif", where 2019 is the year of data collection, NCMP is the effort under which data were collected, AK is the area of data collection, 04VDR0987 is the "Box" number and BareEarth_1mGrid is the data product type.
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.
DEMs that were created from all classes of points (1, 2, 29) at a 1 meter grid size are available by request via email at: coastal.info@noaa.gov. These products have not been reviewed by the NOAA Office for Coastal Management (OCM) and any conclusions drawn from the analysis of this information are not the responsibility of NOAA or OCM.
Distribution Information
-
Create custom data files by choosing data area, product type, map projection, file format, datum, etc.
-
GeoTIFF
Simple download of data files.
These data have been developed from the best available sources. Although efforts have been made to ensure that the data are accurate and reliable, errors and variable conditions originating from physical sources used to develop the data may be reflected in the data supplied. Users must be aware of these conditions and bear responsibility for the appropriate use of the information with respect to possible errors, scale, resolution, rectification, positional accuracy, development methodology, time period, environmental and climatic conditions and other circumstances specific to these data. The user is responsible for understanding the accuracy limitations of the data provided herein. The burden for determining fitness for use lies entirely with the user. The user should refer to the accompanying metadata notes for a description of the data and data development procedures.
These data depict the heights at the time of the survey and are only accurate for that time. Acknowledgement of the Joint Airborne Lidar Bathymetry Technical Center of eXpertise (JALBTCX) would be appreciated in any publications or derived products. The data herein, including but not limited to geographic data, tabular data, analytical data, electronic data structures or files, are provided "as is" without warranty of any kind, either expressed or implied, or statutory, including, but not limited to, the implied warranties or merchantability and fitness for a particular purpose. The entire risk as to the quality and performance of the data is assumed by the user. No guarantee of accuracy is granted, nor is any responsibility for reliance thereon assumed. In no event shall the U.S. Army Corps of Engineers, Mobile District Office, Spatial Data Branch be liable for direct, indirect, incidental, consequential or special damages of any kind, including, but not limited to, loss of anticipated profits or benefits arising out of use of or reliance on the data. The Spatial Data Branch does not accept liability for any damages or misrepresentation caused by inaccuracies in the data or as a result of changes to the data caused by system transfers or other transformations or conversions, nor is there responsibility assumed to maintain the data in any manner or form. Users should be aware that temporal changes may have occurred since this dataset was collected and that some parts of these data may no longer represent actual surface conditions. Users should not use these data for critical applications without a full awareness of its limitations.
Controlled Theme Keywords
BATHYMETRY, COASTAL ELEVATION, COASTAL LANDFORMS, COASTAL PROCESSES, DOD/USARMY/USACE/SAM/MOBILE/OPJ/JALBTCX, elevation, imageryBaseMapsEarthCover, LAND USE CLASSES, oceans, SEAFLOOR TOPOGRAPHY, 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
https://coast.noaa.gov
Metadata Contact
NOAA Office for Coastal Management (NOAA/OCM)
coastal.info@noaa.gov
(843) 740-1202
https://coast.noaa.gov
Extents
-168.96509° W,
-134.637251° E,
68.361331° N,
56.222919° S
2019-07-09 - 2019-07-28
Item Identification
Title: | 2019 USACE NCMP Topobathy Lidar DEM: Alaska |
---|---|
Short Name: | ak2019_usace_dem_m9055_metadata |
Status: | Completed |
Creation Date: | 2020 |
Publication Date: | 2020 |
Abstract: |
These files contain rasterized topobathy lidar elevations generated from data collected by the Coastal Zone Mapping and Imaging Lidar (CZMIL) system. CZMIL integrates a lidar sensor with simultaneous topographic and bathymetric capabilities, a digital camera and a hyperspectral imager on a single remote sensing platform for use in coastal mapping and charting activities. Native lidar data is not generally in a format accessible to most Geographic Information Systems (GIS). Specialized in-house and commercial software packages are used to process the native lidar data into 3-dimensional positions that can be imported into GIS software for visualization and further analysis. Horizontal positions, provided in decimal degrees of latitude and longitude, are referenced to the North American Datum of 1983 National Adjustment of 2011 (NAD83 (2011)). Vertical positions are referenced to the NAD83 (2011) ellipsoid and provided in meters. The National Geodetic Survey's (NGS) GEOID12B model is used to transform the vertical positions from ellipsoid to orthometric heights referenced to the North American Vertical Datum of 1988 (NAVD88). The 3-D position data are sub-divided into a series of LAS files, which are tiled into 1-km by 1-km boxes defined by the Military Grid Reference System. The LAS file index is provided by the shape files, "MGRS_1km_04V.shp ", and the numbers used to identify files are in the "Box" field of the shape file. The data file naming convention is based on the year, effort, area, "Box" number and data product type. An example file name is "2019_NCMP_AK_04VDR0987_BareEarth_1mGrid.tif", where 2019 is the year of data collection, NCMP is the effort under which data were collected, AK is the area of data collection, 04VDR0987 is the "Box" number and BareEarth_1mGrid is the data product type. 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. DEMs that were created from all classes of points (1, 2, 29) at a 1 meter grid size are available by request via email at: coastal.info@noaa.gov. These products have not been reviewed by the NOAA Office for Coastal Management (OCM) and any conclusions drawn from the analysis of this information are not the responsibility of NOAA or OCM. |
Purpose: |
This data was collected by USACE on behalf of the USACE NCMP to assess elevations above and below water along the coast of Alaska. |
Keywords
Theme Keywords
Thesaurus | Keyword |
---|---|
Global Change Master Directory (GCMD) Data Center Keywords |
DOD/USARMY/USACE/SAM/MOBILE/OPJ/JALBTCX > Joint Airborne Lidar Bathymetry Technical Center of Expertise, Mobile District, South Atlantic Division, U.S. Army Corps of Engineers, U.S. Army, U.S. Department of Defense
|
Global Change Master Directory (GCMD) Science Keywords |
EARTH SCIENCE > HUMAN DIMENSIONS > ENVIRONMENTAL GOVERNANCE/MANAGEMENT > LAND MANAGEMENT > LAND USE CLASSES
|
Global Change Master Directory (GCMD) Science Keywords |
EARTH SCIENCE > LAND SURFACE > GEOMORPHIC LANDFORMS/PROCESSES > COASTAL LANDFORMS
|
Global Change Master Directory (GCMD) Science Keywords |
EARTH SCIENCE > LAND SURFACE > GEOMORPHIC LANDFORMS/PROCESSES > COASTAL PROCESSES
|
Global Change Master Directory (GCMD) Science Keywords |
EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION
|
Global Change Master Directory (GCMD) Science Keywords |
EARTH SCIENCE > OCEANS > BATHYMETRY/SEAFLOOR TOPOGRAPHY > BATHYMETRY
|
Global Change Master Directory (GCMD) Science Keywords |
EARTH SCIENCE > OCEANS > BATHYMETRY/SEAFLOOR TOPOGRAPHY > SEAFLOOR TOPOGRAPHY
|
Global Change Master Directory (GCMD) Science Keywords |
EARTH SCIENCE > OCEANS > COASTAL PROCESSES > COASTAL ELEVATION
|
ISO 19115 Topic Category |
elevation
|
ISO 19115 Topic Category |
imageryBaseMapsEarthCover
|
ISO 19115 Topic Category |
oceans
|
UNCONTROLLED | |
None | U.S. Army Corps of Engineers (USACE) |
Temporal Keywords
Thesaurus | Keyword |
---|---|
UNCONTROLLED | |
None | 2019 |
None | July |
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
|
Global Change Master Directory (GCMD) Location Keywords |
VERTICAL LOCATION > SEA FLOOR
|
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: | Other |
Maintenance Frequency: | As Needed |
Data Presentation Form: | Model (digital) |
Distribution Liability: |
These data have been developed from the best available sources. Although efforts have been made to ensure that the data are accurate and reliable, errors and variable conditions originating from physical sources used to develop the data may be reflected in the data supplied. Users must be aware of these conditions and bear responsibility for the appropriate use of the information with respect to possible errors, scale, resolution, rectification, positional accuracy, development methodology, time period, environmental and climatic conditions and other circumstances specific to these data. The user is responsible for understanding the accuracy limitations of the data provided herein. The burden for determining fitness for use lies entirely with the user. The user should refer to the accompanying metadata notes for a description of the data and data development procedures. Any conclusions drawn from the analysis of this information are not the responsibility of USACE, JALBTCX, the Office for Coastal Management, or its partners. |
Data Set Credit: | Acknowledgement of the Joint Airborne Lidar Bathymetry Technical Center of eXpertise (JALBTCX) would be appreciated in any publications or derived products. |
Support Roles
Data Steward
Date Effective From: | 2020 |
---|---|
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
Date Effective From: | 2020 |
---|---|
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
Date Effective From: | 2020 |
---|---|
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
Date Effective From: | 2020 |
---|---|
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
W° Bound: | -168.96509 | |
---|---|---|
E° Bound: | -134.637251 | |
N° Bound: | 68.361331 | |
S° Bound: | 56.222919 |
Extent Group 1 / Time Frame 1
Time Frame Type: | Range |
---|---|
Start: | 2019-07-09 |
End: | 2019-07-28 |
Spatial Information
Spatial Representation
Representations Used
Grid: | Yes |
---|
Reference Systems
Reference System 1
Coordinate Reference System |
|||||||||||||||||||||||
|
Reference System 2
Coordinate Reference System |
|||||||||||||||||||||||||||||||||||||||||
|
Access Information
Security Class: | Unclassified |
---|---|
Data Access Procedure: |
Data is available online for bulk and custom downloads. |
Data Access Constraints: |
These data have been developed from the best available sources. Although efforts have been made to ensure that the data are accurate and reliable, errors and variable conditions originating from physical sources used to develop the data may be reflected in the data supplied. Users must be aware of these conditions and bear responsibility for the appropriate use of the information with respect to possible errors, scale, resolution, rectification, positional accuracy, development methodology, time period, environmental and climatic conditions and other circumstances specific to these data. The user is responsible for understanding the accuracy limitations of the data provided herein. The burden for determining fitness for use lies entirely with the user. The user should refer to the accompanying metadata notes for a description of the data and data development procedures. |
Data Use Constraints: |
These data depict the heights at the time of the survey and are only accurate for that time. Acknowledgement of the Joint Airborne Lidar Bathymetry Technical Center of eXpertise (JALBTCX) would be appreciated in any publications or derived products. The data herein, including but not limited to geographic data, tabular data, analytical data, electronic data structures or files, are provided "as is" without warranty of any kind, either expressed or implied, or statutory, including, but not limited to, the implied warranties or merchantability and fitness for a particular purpose. The entire risk as to the quality and performance of the data is assumed by the user. No guarantee of accuracy is granted, nor is any responsibility for reliance thereon assumed. In no event shall the U.S. Army Corps of Engineers, Mobile District Office, Spatial Data Branch be liable for direct, indirect, incidental, consequential or special damages of any kind, including, but not limited to, loss of anticipated profits or benefits arising out of use of or reliance on the data. The Spatial Data Branch does not accept liability for any damages or misrepresentation caused by inaccuracies in the data or as a result of changes to the data caused by system transfers or other transformations or conversions, nor is there responsibility assumed to maintain the data in any manner or form. Users should be aware that temporal changes may have occurred since this dataset was collected and that some parts of these data may no longer represent actual surface conditions. Users should not use these data for critical applications without a full awareness of its limitations. |
Distribution Information
Distribution 1
Download URL: | https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=9055 |
---|---|
Distributor: | NOAA Office for Coastal Management (NOAA/OCM) (2020 - Present) |
File Name: | Customized Download |
Description: |
Create custom data files by choosing data area, product type, map projection, file format, datum, etc. |
File Type (Deprecated): | Zip |
Compression: | Zip |
Distribution 2
Download URL: | https://noaa-nos-coastal-lidar-pds.s3.us-east-1.amazonaws.com/dem/USACE_AK_DEM_2019_9055/index.html |
---|---|
Distributor: | NOAA Office for Coastal Management (NOAA/OCM) (2020 - Present) |
File Name: | Bulk Download |
Description: |
Simple download of data files. |
File Type (Deprecated): | GeoTIFF |
Distribution Format: | GeoTIFF |
URLs
URL 1
URL: | https://coast.noaa.gov/dataviewer |
---|---|
Name: | Data Access Viewer |
URL Type: |
Online Resource
|
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
URL: | https://coast.noaa.gov/dataregistry |
---|---|
Name: | Digital Coast |
URL Type: |
Online Resource
|
URL 3
URL: | https://coast.noaa.gov/ |
---|---|
Name: | NOAA Office for Coastal Management (OCM) |
URL Type: |
Online Resource
|
Description: |
Information on the NOAA Office for Coastal Management (OCM). |
URL 4
URL: | https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid12b/8837/supplemental/ak2019_alaska_m8837.kmz |
---|---|
Name: | Browse Graphic |
URL Type: |
Browse Graphic
|
File Resource Format: | kmz |
Description: |
This graphic shows the lidar coverage for the 2019 topobathy lidar acquisition along the coast of Alaska. |
URL 5
URL: | https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=8837 |
---|---|
URL Type: |
Online Resource
|
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. |
Technical Environment
Description: |
Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS 10.1.0.3035 |
---|
Data Quality
Accuracy: |
Every effort within operational constraints was made to acquire data that meets specifications as outline in this project's Statement of Work. Per flight block, elevations in areas of swath overlap are internally consistent and meet CZMIL specifications. Annomalous high and/or low elevation values have been removed, and point cloud classificaiton algorithms have been validated via manual review and QC. Temporal differences in elevation exist in areas of active nearshore processes from the dune to the depth of closure. JALBTCX conducts operations in a manner to ameliorate temporal differences, to include the collection of entire flight blocks within single missions. For a given flight block, it's adjacent flight blocks are captured within 3 days as weather and airspace permit. |
---|---|
Horizontal Positional Accuracy: |
CZMIL topographic data - Compiled to meet 1 m horizontal accuracy at 95% confidence level. CZMIL bathymetric data - Compiled to meet 3.5 + 0.05d m horizontal accuracy at 95% confidence level, d is depth. JALBTCX evaluates the horizonal accuracy of the final data coverage against available basemap imagery products. The final lidar point cloud is gridded according to procedures defined in the JALBTCX Standard Operating Guide and Appendices (SOGA). The grid products are then visually compared to basemap imagery products to verify the horizontal positions of large buildings and other urban features with the data coverage. |
Vertical Positional Accuracy: |
CZMIL topographic data - Compiled to meet 19.6 cm vertical accuracy at 95% confidence level. CZMIL bathymetric shallow FOV data - Compiled to meet SQRT((0.25^2) +((0.0075d)^2)) m vertical accuracy at 95% confidence level, d is depth. CZMIL bathymetric deep FOV data - Compiled to meet SQRT((0.30^2) +((0.013d)^2)) m vertical accuracy at 95% confidence level, d is depth. JALBTCX evaluates the vertical accuracy of the final data coverage against traditional ground-truth data. Ground-truth data is acquired and utilized according to specifications outlined in the JALBTCX Standard Operating Guide and Appendices (SOGA) as well as the USGS Lidar BaseSpecification. The final lidar point cloud at every project ground-truth location is compared against ground-truth points in the 'bare_ground' class. Comparisons are performed in the QCoherent LP360 software package, and the final results are output to JALBTCX's Ground Truth Comparison Report. |
Completeness Measure: |
Planned data coverage for this dataset included a 1500-meter swath of the Alaska shoreline. Topographic lidar coverage was obtained from the shoreline onshore 500 meters. Bathymetric lidar coverage extends from the shoreline offshore 1000 meters or to laser exinction, whichever occurs first. The planned data densitiy is 70 centimeters on land and in shallow water. In deeper water the planned data density decreases to 2 meters. Gaps or data holidays may exist in the data coverage. They arise due to a number of operational and environmental conditions, including but not limited to, airspace restrictions, high terrain, active surf, low-reflectivity bottom substrate materials and turbidity in the water column. Please see the Report of Survey for additional details. Every effort within operational constraints was made to achieve the intended data coverage and planned point densities. |
Completeness Report: |
This data set covers the spatial extent of topographic lidar data obtained during this survey. |
Conceptual Consistency: |
No discernable offsets or horizontal shifts were found during visual inspecton of the lidar-derived grid products against basemap imagery products. |
Quality Control Procedures Employed: |
JALBTCX evaluates final data coverage using techniques that are common to the lidar industry. These techniques are performed in a 3D environment for visual review of the final data coverage and verification of data alongside lidar waveforms and imagery collected concurrent with the lidar. Data reviewers perform checks to verify (1) extreme high and/or low elevation values have been invalidated, (2) elevations in areas of swath overlap are internally consistent, (3) binned standard deviation values meet CZMIL specifications, (4) point cloud classifications are valid, and (4) CZMIL processing modes are valid. |
Lineage
Lineage Statement: |
CZMIL data is processed from raw lidar waveforms to point clouds using the CZMIL HydroFusion software package. Point clouds are then classified and edited in industry-standard software packages. Derivative data products are generated through the application of gridding and contouring algorithms in a GIS environment. The data processing workflow, including software packages, algorithms and parameters are provided in detail, herein this metadata as Process Steps. |
---|
Sources
Originator of data
Contact Role Type: | Originator |
---|---|
Contact Type: | Organization |
Contact Name: | USACE JALBTCX |
Process Steps
Process Step 1
Description: |
These data were collected using the CZMIL system. It is owned and operated by the U.S. Army Corps of Engineers (USACE). The system collects topobathy lidar data at 10 kHz and RGB imagery at 2 Hz. A CASI-1500 hyperspectral line scanner is integrated with the system as well. Aircraft position, velocity and acceleration information are collected through a combination of Novatel and POS A/V 610 equipment. All raw data streams are transferred to the office for downloading and processing in CZMIL’s HydroFusion software. Aircraft position data are processed using POSPac software and the results are combined with the lidar data to produce 3-D positions for each lidar shot. Upon inspection and QA/QC in the software packages Fledermaus and PFM_ABE, anomalous data are flagged as invalid and have the withheld bit set. |
---|---|
Process Date/Time: | 2019-07-09 00:00:00 |
Process Step 2
Description: |
LAS files are imported into TerraScan V13 module within Microstation V8i, classifies valid topobathy data as ground points (2) and unclassified points (1), and valid bathymetric points (29). Upon completion the macro, the classification results undergo quality control and any misclassified points are manually edited. In areas of dense vegetation the bare earth ground points might be incorrectly classified due to the inability of the laser to penetrate the canopy and reach the bare ground. In these areas, JALBTCX defaults to the algorithm’s “ground” surface instead of manually reclassifying those points. They are partitioned into a series of 1-km delivery boxes, one Classified LAS file per box. The format of the file is LAS version 1.2. Data are classified as 1 (valid non-ground topographic data), 2 (valid ground topographic data), and 29 (valid bathymetric data). The National Geodetic Survey's (NGS) GEOID12B model is used to transform the horizontal positions from UTM to Geographic coordinates referenced to the North American Datum of 1983 National Adjustment of 2011 (NAD83 NA11). Vertical positions are also transformed from ellipsoid to orthometric heights referenced to the North American Vertical Datum of 1988 (NAVD88). The files are then compressed with the open-source LASzip utility, which is part of the LAStools package (LAStools, "Efficient LiDAR Processing Software" (version 170923, unlicenced)), obtained from http://rapidlasso.com/LAStools |
---|---|
Process Date/Time: | 2019-11-03 00:00:00 |
Process Step 3
Description: |
Data classified as ground points (2), and bathymetric points (29) in the las files are converted to a grid by generating a triangulated irregular network (TIN) and then extracting the grid node elevations from the TIN surface. The origin point of the grid is located at a horizontal position whose value is evenly divisible by the 1m grid resolution such that rasters from subsequent surveys have common cell boundaries. JALBTCX uses Quick Terrain Modeler V8 to perform this operation utilizing the following parameters; “Legacy Triangulation”, "Max Sample Excursion - 30000”, “Max Triangle Side – 30000”, and “Tiling Settings Snap to Grid (Expand)." The grid is exported from Quick Terrain Modeler as an ESRI ASCII Z grid file. Utilizing an in-house python script within ESRI ArcMap V10.2, the ASCII Z grid file is converted to a tif-format raster file whose projection is defined as “The North American Datum of 1983 (2011).” The raster is then multiplied against a corresponding 1m Grid mask raster, a mask image produced from JALBTCX’s 1m Grid, in ESRI’s Raster Calculator to remove interpolated areas where data does not exist |
---|---|
Process Date/Time: | 2019-12-11 00:00:00 |
Process Step 4
Description: |
The NOAA Office for Coastal Management (OCM) received files for the project area in tif format from JALBTCX. The bare earth raster files were at a 1 m grid spacing. The data were in geographic coordinates and NAVD88 (Geoid12B) elevations in meters. OCM assigned the horizontal EPSG code of 6318 and the vertical EPSG code of 5703 and copied the raster files to https for Digital Coast storage and provisioning purposes. |
---|---|
Process Date/Time: | 2020-04-27 00:00:00 |
Process Contact: | Office for Coastal Management (OCM) |
Related Items
Item Type | Relationship Type | Title |
---|---|---|
Data Set (DS) | Cross Reference |
2019 USACE NCMP Topobathy Lidar: Alaska |
Catalog Details
Catalog Item ID: | 59419 |
---|---|
GUID: | gov.noaa.nmfs.inport:59419 |
Metadata Record Created By: | Rebecca Mataosky |
Metadata Record Created: | 2020-04-27 13:52+0000 |
Metadata Record Last Modified By: | Kirk Waters |
Metadata Record Last Modified: | 2024-01-10 19:12+0000 |
Metadata Record Published: | 2024-01-10 |
Owner Org: | OCMP |
Metadata Publication Status: | Published Externally |
Do Not Publish?: | N |
Metadata Last Review Date: | 2022-03-16 |
Metadata Review Frequency: | 1 Year |
Metadata Next Review Date: | 2023-03-16 |