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Summary
Item Identification
Keywords
Physical Location
Data Set Info
Support Roles
Extents
Spatial Info
Access Info
Distribution Info
URLs
Tech Environment
Data Quality
Lineage
Related Items
Catalog Details

Summary

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Short Citation
OCM Partners, 2024: 2014 FEMA Lidar DEM: Ketchikan, Alaska, https://www.fisheries.noaa.gov/inport/item/52496.
Full Citation Examples

Abstract

Digital Elevation model, derived from a lidar point cloud data, developed to support FEMA flood risk analysis and mapping in Ketchikan, Alaska. Point cloud is classified as ground (class 2) and other (class 1). The data was collected under a FEMA contract to the Strategic Alliance for Risk Reduction (STARR) with an accuracy requirement to support 2-foot contours. Original tasking indicates additional classes would be populated (7, 9, 10, 11), but they are not in the data set.

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 in horizontal meters and feet. Vertical units are meters.

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be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions.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

-131.890301° W, -131.454155° E, 55.517998° N, 55.290125° S

Time Frame 1
2014-11-30

Item Identification

Title: 2014 FEMA Lidar DEM: Ketchikan, Alaska
Short Name: 2014 Ketchikan, Alaska
Status: Completed
Publication Date: 2014-11-30
Abstract:

Digital Elevation model, derived from a lidar point cloud data, developed to support FEMA flood risk analysis and mapping in Ketchikan, Alaska. Point cloud is classified as ground (class 2) and other (class 1). The data was collected under a FEMA contract to the Strategic Alliance for Risk Reduction (STARR) with an accuracy requirement to support 2-foot contours. Original tasking indicates additional classes would be populated (7, 9, 10, 11), but they are not in the data set.

Purpose:

Terrain data are used to represent the topography of a watershed and/or floodplain environment and to extract useful information for hydraulic and hydrologic models. (Source: FEMA Guidelines and Standards for Flood Risk Analysis and Mapping.)

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 > OCEANS > COASTAL PROCESSES > COASTAL ELEVATION
ISO 19115 Topic Category
elevation
UNCONTROLLED
FEMA NFIP Topic Category Bare Earth
FEMA NFIP Topic Category Breaklines
FEMA NFIP Topic Category Contours
FEMA NFIP Topic Category DEM
FEMA NFIP Topic Category Digital Elevation Model
FEMA NFIP Topic Category Elevation Data
FEMA NFIP Topic Category Flow Vectors
FEMA NFIP Topic Category Hydro Enforced DEM
FEMA NFIP Topic Category Land Surface
FEMA NFIP Topic Category LIDAR
FEMA NFIP Topic Category Relief
FEMA NFIP Topic Category Slope
FEMA NFIP Topic Category TIN
FEMA NFIP Topic Category Topography
FEMA NFIP Topic Category Triangulated Irregular Network

Spatial Keywords

Thesaurus Keyword
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

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: Unknown
Data Presentation Form: FEMA-DCS-Terrain
Entity Attribute Detail Citation:

FEMA's Guidelines and Standards for Flood Risk Analysis and Mapping contains a detailed description of the data themes and references to other relevant information.

Distribution Liability:

No warranty expressed or implied is made by FEMA regarding the utility of the data on any other system nor shall the act of distribution constitute any such warranty.

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: Federal Emergency Management Agency

Support Roles

Data Steward

CC ID: 752629
Date Effective From: 2018-05-01
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: 752630
Date Effective From: 2018-05-01
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: 752631
Date Effective From: 2018-05-01
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: 752632
Date Effective From: 2018-05-01
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: 1290941
W° Bound: -131.890301
E° Bound: -131.454155
N° Bound: 55.517998
S° Bound: 55.290125

Extent Group 1 / Time Frame 1

CC ID: 1290940
Time Frame Type: Discrete
Start: 2014-11-30

Spatial Information

Spatial Resolution

Horizontal Distance: 3.0 Foot

Access Information

Security Class: Unclassified
Data Access Procedure:

Data is available online for 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: 752636
Start Date: 2018-05-01
End Date: Present
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=8522
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2018-05-01 - 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.

Compression: Zip

Distribution 2

CC ID: 752637
Start Date: 2018-05-01
End Date: Present
Download URL: https://noaa-nos-coastal-lidar-pds.s3.us-east-1.amazonaws.com/dem/AK_Ketchikan_FEMA_DEM_2014_8522/index.html
Distributor: NOAA Office for Coastal Management (NOAA/OCM) (2018-05-01 - Present)
File Name: Bulk Download
Description:

Bulk download of data files in the original coordinate system in horizontal meters and feet. Vertical units are meters.

File Type (Deprecated): GeoTIFF
Distribution Format: GeoTIFF

URLs

URL 1

CC ID: 752624
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: 752625
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: 752626
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid12b/8521/supplemental/ketchikan_extent_2014_m8521.kmz
Name: Browse graphic
URL Type:
Browse Graphic
File Resource Format: KML
Description:

This graphic displays the footprint for this lidar data set.

URL 4

CC ID: 752627
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid12b/8521/supplemental/02130C_Elevation_Data_QA_Report_for_Ketchikan_Alaska.pdf
Name: Dataset report
URL Type:
Online Resource
File Resource Format: PDF
Description:

Link to data set QA report.

URL 5

CC ID: 752672
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid12b/8521/supplemental/02130C_Ketchikan_FEMA_M-11_Certificate_of_Compliance.pdf
Name: Certificate of compliance
URL Type:
Online Resource
File Resource Format: pdf
Description:

FEMA certificate of compliance

Technical Environment

Description:

Original data development environment may vary. Finishing of the data is done using Esri’s ArcGIS software. The submitted file geodatabase was created using ArcGIS version 10.0.

Data Quality

Horizontal Positional Accuracy:

The LiDAR data horizontal accuracy is in compliance with the National Standard for Spatial Data Accuracy (NSSDA) RMSE estimation of elevation data in support of 2ft. contour mapping products as it is referenced in the FEMA Guidelines and Standards for Flood Risk Analysis and Mapping.

Vertical Positional Accuracy:

Deliverables were tested by for both vertical and horizontal accuracy. The vertical unit of the data file is in meters with 2-decimal point precision. ASPRS, USGS, and FEMA vertical accuracy requirements were used to test lidar dataset.

Fundamental Vertical Accuracy (FVA) tested against survey data points measured 0.0513 meters at 95% confidence and and RMSE of 0.0496 RMSE. The errors were not normally distributed. See the QA report for more details.

Completeness Report:

The bare earth surface data is an estimation of the bare earth surface and does not include vegetative and built features. Likewise, it contains estimates of water edges at the time of data collection, and may not reflect current conditions. The bare earth surface will contain voids where insufficient energy was reflected from the surface to generate a valid return from the terrain. Voids in the bare earth surface tend to occur in heavily vegetated areas, water bodies, and beneath buildings, motor vehicles, bridges etc. Fresh or wet asphalt, wet sand and certain types of vegetation can also cause voids or anomalous elevations. The data may have been further processed to remove points found to be within delineated water bodies. Low confidence areas are delineated and provided in a separate dataset.

Conceptual Consistency:

Checks were performed to ensure the data files can be opened, are georeferenced properly, and cover the geographic area completely. Additionally, field survey checkpoints are obtained to evaluate the accuracy of LiDAR products. A minimum of 100 checkpoints are tested in a project area. At least 20 for 5 different land vegetation categories (forest, built-up, scrub, weeds/crop, and bare-earth/low grass) are tested with forested areas requiring a minimum of 40 checkpoints. A statistical analysis between the difference in elevations of the field survey checkpoints and LiDAR-derived, bare earth elevations at the same locations provides a quality assessment of the LiDAR data.

Lineage

Sources

Ketchikan 2ft Contours

CC ID: 1290926
Publish Date: 2014-12-31
Extent Type: Discrete
Extent Start Date/Time: 2014-12-31
Source Contribution:

KETCHIKAN, AK 2ft Contours.

Ketchikan 3ft Digital Elevation Models

CC ID: 1290927
Publish Date: 2014-12-31
Extent Type: Discrete
Extent Start Date/Time: 2014-12-31
Source Contribution:

KETCHIKAN, AK 3ft Bare Earth Digital Elevation Models.

Ketchikan Collection Area, Flight Lines, LiDAR Swath Index and LiDAR Tile Index

CC ID: 1290928
Publish Date: 2014-12-31
Extent Type: Discrete
Extent Start Date/Time: 2014-12-31
Source Contribution:

KETCHIKAN, AK LiDAR Acquisition vector data.

Ketchikan Ground Control Survey

CC ID: 1290929
Publish Date: 2014-12-31
Extent Type: Discrete
Extent Start Date/Time: 2014-12-31
Source Contribution:

KETCHIKAN, AK LiDAR Acquisition ground control survey.

Ketchikan Ketchikan Classified Tiled Point Cloud

CC ID: 1290930
Publish Date: 2014-12-31
Extent Type: Discrete
Extent Start Date/Time: 2014-12-31
Source Contribution:

KETCHIKAN, AK LiDAR Acquisition Classified LAS Bare Earth point cloud data.

Ketchikan Ketchikan Unclassified Swath Point Cloud

CC ID: 1290931
Publish Date: 2014-12-31
Extent Type: Discrete
Extent Start Date/Time: 2014-12-31
Source Contribution:

KETCHIKAN, AK LiDAR Acquisition Unclassified LAS raw point cloud data.

Ketchikan LiDAR Quality Assurance Report

CC ID: 1290932
Publish Date: 2014-12-31
Extent Type: Discrete
Extent Start Date/Time: 2014-12-31
Source Contribution:

Quality Assurace Report for LiDAR and derivative products part of the Technical Support Data Notebook that contains complete narrative on the acquisition and processing of the LiDAR dataset, including area diagram, reports, metadata and other supporting documentation.

Ketchikan Pre-Flight Planning Report and Post Flight Report

CC ID: 1290933
Publish Date: 2014-12-31
Extent Type: Discrete
Extent Start Date/Time: 2014-12-31
Source Contribution:

KETCHIKAN, AK LiDAR Acquisition Documentation.

Process Steps

Process Step 1

CC ID: 1290934
Description:

Terrain data used for flood risk analysis go through LiDAR preliminary processing and the unclassified point cloud data are tested as specified in the USGS National Geospatial Program Base LiDAR Specification Version 1.0. Where the Mapping Activity Statement (MAS) requires bare earth post-processing of the floodplain area of interest (AOI), the elevation data are tested and comply with both the Fundamental Vertical Accuracy (FVA) and Consolidated Vertical Accuracy (CVA) requirements. Where no bare earth post-processing is specified, only the FVA requirements apply for LiDAR preliminary processing.

Process Date/Time: 2014-09-30 00:00:00

Process Step 2

CC ID: 1290935
Description:

Ground Survey:

RTK GPS based surveys were utilized to support both processing and testing of LiDAR data within FEMA designated Areas of Interest (AOIs). Geographically distinct ground points were surveyed using GPS technology throughout the AOIs to provide support for three distinct tasks.

Task 1: Ground control monuments utilized for the STARR Ketchikan LiDAR dataset. Ground control monuments are used to provide redundant control within 13 nautical miles of mission areas for LiDAR flights, as well as the collection of ground control points using real-time kinematic (RTK) survey techniques. The horizontal datum for this dataset is NAD83 (2011), the vertical datum is NAVD88, Geoid 12A, and the data is projected in Alaska State Plane Zone 1. Units are in US Survey Feet.

Task 2: RTK (real time kinematic) ground control points collected for the STARR Ketchikan LiDAR dataset. RTK ground control points are used to correct and verify the vertical accuracy of the LiDAR data. The horizontal datum for this dataset is NAD83 (2011), the vertical datum is NAVD88, Geoid 12A, and the data is projected in Alaska State Plane Zone 1. Units are in US Survey Feet.

Task 3: Land cover class ground check points collected for the STARR Ketchikan LiDAR dataset. Land class ground check points are used to assess the vertical accuracy of the LiDAR data and are collected using real time kinematic (RTK) survey techniques. The horizontal datum for this dataset is NAD83 (2011), the vertical datum is NAVD88, Geoid 12A, and the data is projected in Alaska State Plane Zone 1. Units are in US Survey Feet.

Process Date/Time: 2014-07-01 00:00:00

Process Step 3

CC ID: 1290936
Description:

LiDAR Acquisition:

General: LiDAR collection was collected using a Leica ALS70 system mounted in a Piper Navajo airplane. Yielded an average pulse density of >= 4 pulses/square meter over the Ketchikan Project Area.

Swath Acquisition: This swath dataset represents the STARR Ketchikan LiDAR study area. This data is delineated in 4800x4800 ft tiles. Tile naming is derived from the 4 four digits of the easting and first four digits of the northing coordinates of the lower left corner. Data is unclassified (class 0). The horizontal datum for this dataset is NAD83 (2011), the vertical datum is NAVD88, Geoid 12A, and it is projected in Alaska State Plane Zone 1. Units are in US Survey Feet. Quantum Spatial collected the STARR Ketchikan LiDAR data for STARR on 07/12/2014 and 07/13/2014 further information is available in the Ketchikan Post-Flight Aerial Acquisition Report.

All areas were surveyed with an opposing flight line side-lap of >=50% (=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).

All swath data were classified as Class 0 or Unclassified.

Leica ALS70 Instrument Parameters:

Beam diameter: 37 cm cm,

Pulse rate: 175 kHz,

Maximum returns: 4,

Speed: 150 knots,

Overlap: 60 %,

Laser power: 93.6 %,

Field of view (FOV): 30 degrees,

Beam wavelength: 1064 nm,

Frequency of GPS sampling: 2 Hz,

Frequency of IMU sampling: 200 Hz,

Swath width: 857 m,

AGL: 5207 - 5315 MSL m,

Average pulse density: 4

Process Date/Time: 2014-07-13 00:00:00

Process Step 4

CC ID: 1290937
Description:

Bare Earth Processing:

QSI processing staff initiated a suite of automated and manual techniques to process the data into ASPRS Class 2 Bare Earth. The calibrated and filt ered LiDAR point cloud was hand checked for accuracy. Generate bare earth models as triangulated surfaces. The calibrated and filtered LiDAR point cloud was hand checked for accuracy. All points were placed in one of the following categories: 1 Unclassified, 2 Ground, 7 Noise, and 12 Overlap Points. Model Key points were then generated from the Ground points and placed in Category 8. Requested elevation values were evaluated for the Consolidated Vertical Accuracy (CVA) testing.

Ketchikan Classified LiDAR ASPRS Classifications

1 Unclassified

2 Ground

Process Date/Time: 2014-09-30 00:00:00

Process Step 5

CC ID: 1290938
Description:

Digital Elevation Model tiles were received in ESRI Arc coverage proprietary format from FEMA. Tiles were in Alaska state plane zone 01 US survey feet with vertical units of US survey feet. The vertical datum was NAVD88 using the NGS Geoid12a geoid model. Data were converted to tif format and changed to horizontal and vertical meters for ingest in the Digital Coast Data Access Viewer.

The change of horizontal units was done because the system was not processing the files in US survey feet correctly. This projection does not have an EPSG code. EPSG code 6394 was used for Alaska State Plane Zone 1 NAD83(2011) in meters. Tests showed this data was correctly interpreted in some software, but not all software. The data in both feet and meters is available on the bulk download data access link.

Process Date/Time: 2018-05-01 00:00:00
Process Contact: Office for Coastal Management (OCM)
Source: Ketchikan 3ft Digital Elevation Models

Related Items

Item Type Relationship Type Title
Data Set (DS) Cross Reference 2014 FEMA Lidar: Ketchikan, Alaska

Lidar point cloud source for this DEM

Catalog Details

Catalog Item ID: 52496
GUID: gov.noaa.nmfs.inport:52496
Metadata Record Created By: Kirk Waters
Metadata Record Created: 2018-05-01 08:22+0000
Metadata Record Last Modified By: Kirk Waters
Metadata Record Last Modified: 2024-01-10 19:01+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