Portland, Maine 1/3 arc-second MHW Coastal Digital Elevation Model

browse graphicThumbnail of DEM
NOAA's National Geophysical Data Center (NGDC) is building high-resolution digital elevation models (DEMs) for select U.S. coastal regions. These integrated bathymetric-topographic DEMs are used to support tsunami forecasting and modeling efforts at the NOAA Center for Tsunami Research, Pacific Marine Environmental Laboratory (PMEL). The DEMs are part of the tsunami forecast system SIFT (Short-term Inundation Forecasting for Tsunamis) currently being developed by PMEL for the NOAA Tsunami Warning Centers, and are used in the MOST (Method of Splitting Tsunami) model developed by PMEL to simulate tsunami generation, propagation, and inundation. Bathymetric, topographic, and shoreline data used in DEM compilation are obtained from various sources, including NGDC, the U.S. National Ocean Service (NOS), the U.S. Geological Survey (USGS), the U.S. Army Corps of Engineers (USACE), the Federal Emergency Management Agency (FEMA), and other federal, state, and local government agencies, academic institutions, and private companies. DEMs are referenced to the vertical tidal datum of Mean High Water (MHW) and horizontal datum of World Geodetic System 1984 (WGS84). Grid spacings for the DEMs range from 1/3 arc-second (~10 meters) to 3 arc-seconds (~90 meters).
  • Cite as: NOAA National Geophysical Data Center. 2008: Portland, Maine 1/3 arc-second MHW Coastal Digital Elevation Model. NOAA National Centers for Environmental Information. Accessed [date].
  • NCEI Metadata ID: gov.noaa.ngdc.mgg.dem:606
gov.noaa.ngdc.mgg.dem:606
Search Data
  • DEM text search (search)
    Text search for locating completed and planned DEMs.
  • Bathymetric Data Viewer (search)
    The Bathymetric Data Viewer is an interactive map providing discovery, descriptions, and download capability for bathymetric survey data and digital elevation models archived at NOAA's National Centers for Environmental Information (NCEI).
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Distribution Formats
  • netCDF (Version:4 Classic)
Ordering Instructions Contact NCEI for other distribution options and instructions.
Distributor NOAA National Centers for Environmental Information
ncei.info@noaa.gov
Dataset Point of Contact NOAA National Centers for Environmental Information
ncei.info@noaa.gov
Dataset Point of Contact DEM Information
NOAA National Centers for Environmental Information
dem.info@noaa.gov
Time Period 1861-01-01 to 2007-01-01
Spatial Reference System urn:ogc:def:crs:EPSG::4326urn:ogc:def:datum:EPSG::5868
Spatial Bounding Box Coordinates
West:-70.74
East:-69.63
South:43.00
North:43.99
Spatial Coverage Map
General Documentation
Associated Resources
  • Data Stewardship Maturity Report for Portland, Maine 1/3 arc-second Mean High Water (MHW) Coastal Digital Elevation Model
  • NOAA Tsunami Inundation Gridding Project
    • Bathymetric Data Viewer (search)
      The Bathymetric Data Viewer is an interactive map providing discovery, descriptions, and download capability for bathymetric survey data and digital elevation models archived at NOAA's National Centers for Environmental Information (NCEI).
    • DEM text search (search)
      Text search for locating completed and planned DEMs.
  • Digital Elevation Model of Portland, Maine: Procedures, Data Sources and Analysis
Publication Dates
  • publication: 2008-12-31
Edition First
Data Presentation Form mapDigital
Dataset Progress Status Complete - production of the data has been completed
Historical archive - data has been stored in an offline storage facility
Data Update Frequency As needed
Purpose Developed for the Pacific Marine Environmental Laboratory (PMEL), NOAA Center for Tsunami Research program in support of NOAA's tsunami forecasting and warning efforts.
Use Limitations
  • Not to be used for navigation. Although these data are of high quality and useful for planning and modeling purposes, they are not suitable for navigation. For navigation, please refer to the NOS nautical chart series.
  • Produced by the NOAA National Centers for Environmental Information. Not subject to copyright protection within the United States.
Dataset Citation
  • Cite as: NOAA National Geophysical Data Center. 2008: Portland, Maine 1/3 arc-second MHW Coastal Digital Elevation Model. NOAA National Centers for Environmental Information. Accessed [date].
Cited Authors
  • NOAA National Geophysical Data Center
Publishers
  • NOAA National Centers for Environmental Information
Theme keywords Global Change Master Directory (GCMD) Science Keywords
  • Earth Science > Oceans > Bathymetry/Seafloor Topography > Seafloor Topography
  • Earth Science > Oceans > Bathymetry/Seafloor Topography > Bathymetry
  • Earth Science > Oceans > Bathymetry/Seafloor Topography > Water Depth
  • Earth Science > Land Surface > Topography > Terrain Elevation > Topographical Relief Maps
  • Earth Science > Oceans > Coastal Processes > Coastal Elevation
Uncontrolled
  • Coastal Relief
  • Gridded elevations
  • Integrated bathymetry and topography
Global Change Master Directory (GCMD) Service Keywords
  • DATA ANALYSIS AND VISUALIZATION > GEOGRAPHIC INFORMATION SYSTEMS > WEB-BASED GEOGRAPHIC INFORMATION SYSTEMS
  • DATA MANAGEMENT/DATA HANDLING > DATA SEARCH AND RETRIEVAL
  • DATA ANALYSIS AND VISUALIZATION > VISUALIZATION/IMAGE PROCESSING
Global Change Master Directory (GCMD) Service Keywords
  • DATA ANALYSIS AND VISUALIZATION > GEOGRAPHIC INFORMATION SYSTEMS > WEB-BASED GEOGRAPHIC INFORMATION SYSTEMS
  • DATA MANAGEMENT/DATA HANDLING > DATA SEARCH AND RETRIEVAL
  • DATA ANALYSIS AND VISUALIZATION > VISUALIZATION/IMAGE PROCESSING
Global Change Master Directory (GCMD) Service Keywords
  • DATA ANALYSIS AND VISUALIZATION > GEOGRAPHIC INFORMATION SYSTEMS > WEB-BASED GEOGRAPHIC INFORMATION SYSTEMS
  • DATA MANAGEMENT/DATA HANDLING > DATA SEARCH AND RETRIEVAL
  • DATA ANALYSIS AND VISUALIZATION > VISUALIZATION/IMAGE PROCESSING
Data Center keywords Global Change Master Directory (GCMD) Data Center Keywords
  • DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
  • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
Platform keywords Global Change Master Directory (GCMD) Platform Keywords
  • Models/Analyses > DEM > Digital Elevation Model
Place keywords Global Change Master Directory (GCMD) Location Keywords
  • Continent > North America > United States of America > Maine
  • Ocean > Atlantic Ocean > North Atlantic Ocean
  • Vertical Location > Land Surface
  • Vertical Location > Sea Floor
Uncontrolled
  • Portland
  • Bath
  • Cape Elizabeth
  • Portsmouth
Project keywords Global Change Master Directory (GCMD) Project Keywords
  • ICSU-WDS > International Council for Science - World Data System
  • NOAA OneStop Project
Data Resolution keywords Global Change Master Directory (GCMD) Horizontal Data Resolution Keywords
  • 1 meter - < 30 meters
Global Change Master Directory (GCMD) Vertical Data Resolution Keywords
  • < 1 meter
Use Constraints
  • Use liability: NOAA and NCEI cannot provide any warranty as to the accuracy, reliability, or completeness of furnished data. Users assume responsibility to determine the usability of these data. The user is responsible for the results of any application of this data for other than its intended purpose.
Access Constraints
  • Distribution liability: NOAA and NCEI make no warranty, expressed or implied, regarding these data, nor does the fact of distribution constitute such a warranty. NOAA and NCEI cannot assume liability for any damages caused by any errors or omissions in these data. If appropriate, NCEI can only certify that the data it distributes are an authentic copy of the records that were accepted for inclusion in the NCEI archives.
Other Constraints Cite as: NOAA National Geophysical Data Center. 2008: Portland, Maine 1/3 arc-second MHW Coastal Digital Elevation Model. NOAA National Centers for Environmental Information. Accessed [date].
Fees
  • In most cases, electronic downloads of the data are free. However, fees may apply for custom orders, data certifications, copies of analog materials, and data distribution on physical media.
Lineage information for:dataset
Processor
  • NOAA National Centers for Environmental Information
Processing Steps
  • 2008-10-16T00:00:00 -All datasets obtained by NGDC were converted to common horizontal and vertical datums of WGS84 geographic and Mean High Water, respectively, using FME. They were also converted to common file format, ESRI point shapefiles, for visualization and inspection.
  • 2008-10-31T00:00:00 -Datasets were visually inspected with ArcGIS for identification and editing of data anomalies. Datasets were then compared with overlapping datasets to ensure data consistency.
  • 2008-11-15T00:00:00 -In an effort to overcome this mixing of vertical datums in the NED, NGDC converted the NED dataset from NGVD29/MSL to MHW using ArcGIS. Elevations in the converted data that were greater than or equal to 0.5 meters were extracted directly from the grids. Elevations that were less than 0.5 meters were set to an assigned value of 0.5 meters above MHW to prevent inappropriate coastal flooding, though fortunately, there is significant coastal LiDAR data in the Portland region. The resulting NED data were clipped to the LiDAR coverage areas to limit the effects of this approximate NED vertical datum conversion.
  • 2008-11-20T00:00:00 -xyz files of the bathymetric data were surfaced using GMT's 'surface' tool onto a 1 arc-second grid that interpolated to fill empty cells. Points extracted every 10 meters along the coastline were also included to ensure that the bathymetric grid reached zero at the coast. The resulting Arc ASCII grid was imported into ArcGIS and clipped to the coastline to remove values over land.
  • 2008-12-09T00:00:00 -xyz files for each input dataset were gridded using MB-System's 'mbgrid' tool, which utilizes a high-tension spline interpolation method to fill grid cells with no input elevation values. Preferential weighting was given to more recent, higher-accuracy datasets. Gridding was performed in quadrants, each with a 5% data buffer. The grids were imported in ArcGIS and seamlessly merged to create the final DEM.
  • 2008-12-20T00:00:00 -The DEM was quantitatively evaluated by comparing with source datasets and with elevation values extracted from NGS geodetic monuments. It was visually evaluated by converting to UTM-zone coordinates (units of meters horizontally and vertically) and then creating a slope grid to identify gridding artifacts in the DEM.
Processing Environment Native Dataset Environment: Microsoft Windows 2000 Version 5.2 (Build 3790) Service Pack 2; ESRI ArcCatalog 9.2.4.1420
Source Datasets
  • NOS Hydrographic Surveys
    • NOS Hydrographic Survey Database (download)
      Digital database of NOS hydrographic surveys that date back to the late 19th century.
    • Description of Source: Source Contribution: downloaded from web site. ; Source Type: online
    • Temporal extent used: 1861-01-01 to 2003-01-01
  • Digital Bathymetry for the Gulf of Maine
    • Digital Bathymetry for the Gulf of Maine
      Results and bathymetric grids derived from seafloor surveys in the Gulf of Maine
    • Description of Source: Source Contribution: downloaded from web site. ; Source Type: online
    • Temporal extent used: 1998-01-01 to 1998-01-01
  • Electronic Navigational Charts
    • OCS Electronic Navigational Charts (download)
      Digital database of NOAA nautical chart information.
    • Description of Source: Source Contribution: downloaded from web site. ; Source Type: online
    • Temporal extent used: 2001-01-01 to 2007-01-01
  • NOAA Coastal Services Center Coastal Topographic LiDAR
    • Topographic Change Mapping (download)
      CSC coastal topographic LiDAR
    • Description of Source: Source Contribution: downloaded from web site. ; Source Type: online
    • Temporal extent used: 2000-01-01 to 2004-01-01
  • USGS NED topography
    • USGS National Elevation Dataset (download)
      Digital database of U.S. topography, in raster form (DEM)
    • Description of Source: Source Contribution: downloaded from web site. ; Source Type: online
    • Time Instant: 2008-01-01
  • UNH Multibeam
    • UNH Multibeam (download)
      5m. resolution multibeam survey of the Gulf of Maine
    • Description of Source: Source Contribution: acquired through UNH ftp site ; Source Type: online
    • Time Instant: 2007-01-01
  • Bare Earth DEM
    • JALCTBX Bathy/Topo Bare Earth DEM (offlineAccess)
      Bare Earth, bathymetric and topographic DEM
    • Description of Source: Source Contribution: received by mail.(CD) ; Source Type: digital
    • Temporal extent used: 2007-01-01 to 2007-01-01
  • USACE Hydrographic Surveys
    • USACE Maine District Hydrographic Surveys (download)
      Digital database of hydrographic surveys in Maine
    • Description of Source: Source Contribution: Hydrographic surveys downloaded from web site. ; Source Type: online
    • Time Instant: 2003-01-01
Lineage information for:repository
Processing Steps
  • 2015-04-22T00:00:00 -NOAA created the National Centers for Environmental Information (NCEI) by merging NOAA's National Climatic Data Center (NCDC), National Geophysical Data Center (NGDC), and National Oceanographic Data Center (NODC), including the National Coastal Data Development Center (NCDDC), per the Consolidated and Further Continuing Appropriations Act, 2015, Public Law 113-235. NCEI launched publicly on April 22, 2015.
Acquisition Information (collection)
Instrument
    Platform
    • Digital Elevation Model
    Operation
    • Tsunami Inundation Gridding Project
    Last Modified: 2022-03-25
    For questions about the information on this page, please email:ncei.info@noaa.gov