gov.noaa.nmfs.inport:48104 eng UTF8 dataset Office for Coastal Management 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 2026-04-30T00:00:00 ISO 19115-2 Geographic Information - Metadata Part 2 Extensions for imagery and gridded data ISO 19115-2:2009(E) Inundation Mapping Tidal Surface - Mean Higher High Water NOAA_OCM_MHHW_Metadata 2019 publication NOAA/NMFS/EDM 48104 https://www.fisheries.noaa.gov/inport/item/48104 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/htdata/Inundation/TidalSurfaces/NOAA_OCM_MHHWInterpolatedSurface.zip WWW:LINK-1.0-http--link Citation URL Online Resource download https://coast.noaa.gov/digitalcoast/tools/slr WWW:LINK-1.0-http--link Citation URL Online Resource download https://vdatum.noaa.gov/ WWW:LINK-1.0-http--link Citation URL Online Resource download These data are a derived product of the NOAA VDatum tool and they extend the tool's Mean Higher High Water (MHHW) tidal datum conversion inland beyond its original extent. VDatum was designed to vertically transform geospatial data among a variety of tidal, orthometric and ellipsoidal vertical datums - allowing users to convert their data from different horizontal/vertical references into a common system and enabling the fusion of diverse geospatial data in desired reference levels (http://vdatum.noaa.gov/). However, VDatum's conversion extent does not completely cover tidally-influenced areas along the coast. For more information on why VDatum does not provide tidal datums inland, see http://vdatum.noaa.gov/docs/faqs.html. Because of the extent limitation and since most inundation mapping activities use a tidal datum as the reference zero (i.e., 1 meter of sea level rise on top of Mean Higher High Water), the NOAA Office for Coastal Management created this dataset for the purpose of extending the MHHW tidal datum beyond the areas covered by VDatum. The data do not replace VDatum, nor do they supersede the valid datum transformations VDatum provides. However, the data are based on VDatum's underlying transformation data and do provide an approximation of MHHW where VDatum does not provide one. In addition, the data are in a GIS-friendly format and represent MHHW in NAVD88, which is the vertical datum by which most topographic data are referenced. Data are in the UTM NAD83 projection. Horizontal resolution varies by VDatum region, but is either 50m or 100m. Data are vertically referenced to NAVD88 meters. These data were created to support the mapping of tidally-based inundation scenarios on high resolution digital elevation models. The data represent the MHHW tidal datum referenced to NAVD88, which is the official civilian orthometric datum by which most topographic data are referenced. Acknowledgment of the NOAA Office for Coastal Management as a data source would be appreciated in products developed from these data, and such acknowledgment as is standard for citation and legal practices for data source is expected. 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 asNeeded EARTH SCIENCE > LAND SURFACE > GEOMORPHIC LANDFORMS/PROCESSES > COASTAL PROCESSES > FLOODING EARTH SCIENCE > LAND SURFACE > GEOMORPHIC LANDFORMS/PROCESSES > COASTAL PROCESSES > SEA LEVEL CHANGES EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION > DIGITAL ELEVATION/TERRAIN MODEL (DEM) theme Global Change Master Directory (GCMD) Science Keywords 23.3 CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA OCEAN > ATLANTIC OCEAN > NORTH ATLANTIC OCEAN > CARIBBEAN SEA > PUERTO RICO OCEAN > ATLANTIC OCEAN > NORTH ATLANTIC OCEAN > CARIBBEAN SEA > VIRGIN ISLANDS place Global Change Master Directory (GCMD) Location Keywords 23.3 DEM Digital Elevation Model MHHW elevation flooding inundation mean higher high water sea level rise tidal datum topography theme Conterminous US Puerto Rico US Virgin Islands coastal states place DOC/NOAA/NOS/OCM > Office of Coastal Management, National Ocean Service, NOAA, U.S. Department of Commerce dataCentre Global Change Master Directory (GCMD) Data Center Keywords 2017-04-24 publication 8.5 Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA) https://forum.earthdata.nasa.gov/app.php/tag/GCMD%2BKeywords GCMD Keyword Forum Page Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 22. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords information custodian Inundation project InPort otherRestrictions Cite As: Office for Coastal Management, [Date of Access]: Inundation Mapping Tidal Surface - Mean Higher High Water [Data Date Range], https://www.fisheries.noaa.gov/inport/item/48104. 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: The dataset is provided as is, without warranty to its performance, merchantable state, or fitness for any particular purpose. The entire risk associated with the results and performance of this dataset is assumed by the user. This dataset should be used strictly as a planning reference and not for navigation, permitting, or other legal purposes. otherRestrictions Distribution Liability: Any conclusions drawn from the analysis of this information are not the responsibility of the Office for Coastal Management or its partners. unclassified grid eng; US elevation -124.851 -64.51 17.619 49.005 | Currentness: Publication Date 2007-10-01 2019-10-24 These data do not replace valid VDatum transformations. They do not incorporate VDatum's bounding polygons (or valid transformation areas) - the data extend beyond these areas. 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/htdata/Inundation/TidalSurfaces/NOAA_OCM_MHHWInterpolatedSurface.zip WWW:LINK-1.0-http--link https://coast.noaa.gov/htdata/Inundation/TidalSurfaces/NOAA_OCM_MHHWInterpolatedSurface.zip Online Resource download https://coast.noaa.gov/digitalcoast/tools/slr WWW:LINK-1.0-http--link https://coast.noaa.gov/digitalcoast/tools/slr Online Resource download https://vdatum.noaa.gov/ WWW:LINK-1.0-http--link https://vdatum.noaa.gov/ Online Resource download dataset Completeness Report Data are complete and cover all areas defined by the source data. Conceptual Consistency Standard mapping methods were used to develop the data, which are described in the Process Steps section. Outputs were inspected for errors and inconsistencies, which were addressed and remedied. Buffered Census Counties offshore by 6km. Source VDatum .gtx files were shifted from positive east longitude values to negative west values. The tss grid was subtracted from the MHHW tidal grid. This step resulted in the MHHW tidal datum referenced to an orthometric datum, specifically NAVD88. Each region's orthometric-referenced tidal grid was converted to a point file, where each cell's centroid is a point containing the value of the cell. The point data were then clipped to county boundaries that extend ~6 km offshore to limit the number of points in the interpolation below. 10 and 12-digit hydrologic unit code (HUC) watershed boundaries that intersect the point data were selected. Where VDatum regions overlapped for an area, the VDatum bounding polygons were used to remove points outside of these areas. Where there was still overlap, points from either the higher resolution region or regions covering bays and estuaries were used. Using the Inverse Distance Weighted interpolation method, the point data were used to interpolate the NAVD88-based tidal surface inland, using the selected HUC boundaries as barriers to interpolation. This approach uses only points within the watershed and limits the interpolation to areas only within the watershed. This process was done for both 10 and 12-digit HUC watersheds. The resulting interpolated surfaces were then nested or mosaicked, where the HUC 12 interpolated surface was the primary raster and the HUC 10 surface the secondary. A Euclidean Allocation approach was then used to extend the conversion further inland to areas where the HUC 10 watersheds did not cover the study area. County boundaries were used as the inland limit instead of watersheds since most topographic data are collected and/or available on a county basis. 2016-01-01T00:00:00 Source Contribution: Census County Boundaries, https://www.census.gov/geo/maps-data/data/cbf/cbf_counties.html | Type of Source Media: online Census County Boundaries 2014-01-01 publication Census Bureau 2014 Source Contribution: NOAA VDatum transformation grids for each VDatum region, https://vdatum.noaa.gov/docs/gtx_info.html. | Type of Source Media: online NOAA VDatum Version 4.0.1 2019-10-24 publication NOAA https://vdatum.noaa.gov/ WWW:LINK-1.0-http--link Source Citation URL Source Citation URL information originator 2007-10-01 2019-10-24 Source Contribution: USGS 10 and 12-digit hydrologic unit code (HUC) watershed boundaries from the Watershed Boundary Dataset, http://nhd.usgs.gov/wbd.html | Type of Source Media: online USGS 10 and 12-digit hydrologic unit code (HUC) watershed boundaries 2016-01-06 publication USGS originator 2019-09-04