48104 NOAA_OCM_MHHW_Metadata Data Set Published / External 37230 Inundation Project Completed 2019 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. 10961 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. Theme Global Change Master Directory (GCMD) Science Keywords EARTH SCIENCE > LAND SURFACE > GEOMORPHIC LANDFORMS/PROCESSES > COASTAL PROCESSES > FLOODING Theme Global Change Master Directory (GCMD) Science Keywords EARTH SCIENCE > LAND SURFACE > GEOMORPHIC LANDFORMS/PROCESSES > COASTAL PROCESSES > SEA LEVEL CHANGES Theme Global Change Master Directory (GCMD) Science Keywords EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION > DIGITAL ELEVATION/TERRAIN MODEL (DEM) Theme ISO 19115 Topic Category elevation Spatial Global Change Master Directory (GCMD) Location Keywords CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA Spatial Global Change Master Directory (GCMD) Location Keywords OCEAN > ATLANTIC OCEAN > NORTH ATLANTIC OCEAN > CARIBBEAN SEA > PUERTO RICO Spatial Global Change Master Directory (GCMD) Location Keywords OCEAN > ATLANTIC OCEAN > NORTH ATLANTIC OCEAN > CARIBBEAN SEA > VIRGIN ISLANDS Theme DEM Theme Digital Elevation Model Theme MHHW Theme elevation Theme flooding Theme inundation Theme mean higher high water Theme sea level rise Theme tidal datum Theme topography Spatial Conterminous US Spatial Puerto Rico Spatial US Virgin Islands Spatial coastal states Office for Coastal Management Charleston SC Data Set As Needed Any conclusions drawn from the analysis of this information are not the responsibility of the Office for Coastal Management or its partners. 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. Data Steward 2019 Organization NOAA Office for Coastal Management NOAA/OCM coastal.info@noaa.gov 2234 South Hobson Ave Charleston SC 29405-2413 (843) 740-1202 https://coast.noaa.gov NOAA Office for Coastal Management Home Page Online Resource Distributor 2019 Organization NOAA Office for Coastal Management NOAA/OCM coastal.info@noaa.gov 2234 South Hobson Ave Charleston SC 29405-2413 (843) 740-1202 https://coast.noaa.gov NOAA Office for Coastal Management Home Page Online Resource Metadata Contact 2019 Organization NOAA Office for Coastal Management NOAA/OCM coastal.info@noaa.gov 2234 South Hobson Ave Charleston SC 29405-2413 (843) 740-1202 https://coast.noaa.gov NOAA Office for Coastal Management Home Page Online Resource Point of Contact 2019 Organization NOAA Office for Coastal Management NOAA/OCM coastal.info@noaa.gov 2234 South Hobson Ave Charleston SC 29405-2413 (843) 740-1202 https://coast.noaa.gov NOAA Office for Coastal Management Home Page Online Resource Publication Date -124.851 -64.51 49.005 17.619 Range 2007-10-01 2019-10-24 Yes Unclassified None 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. https://coast.noaa.gov/digitalcoast/tools/slr Online Resource https://coast.noaa.gov/htdata/Inundation/TidalSurfaces/NOAA_OCM_MHHWInterpolatedSurface.zip Online Resource https://vdatum.noaa.gov/ Online Resource 2017-10-31 Date that the source FGDC record was last modified. 2017-11-14 Converted from FGDC Content Standards for Digital Geospatial Metadata (version FGDC-STD-001-1998) using 'fgdc_to_inport_xml.pl' script. Contact Tyler Christensen (NOS) for details. Data are complete and cover all areas defined by the source data. 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. Census County Boundaries Census Bureau 2014-01-01 Discrete 2014 Census County Boundaries, https://www.census.gov/geo/maps-data/data/cbf/cbf_counties.html | Type of Source Media: online NOAA VDatum Version 4.0.1 Organization NOAA Originator 2019-10-24 Range 2007-10-01 2019-10-24 https://vdatum.noaa.gov/ NOAA VDatum transformation grids for each VDatum region, https://vdatum.noaa.gov/docs/gtx_info.html. | Type of Source Media: online USGS 10 and 12-digit hydrologic unit code (HUC) watershed boundaries Organization USGS Originator 2016-01-06 Discrete 2019-09-04 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 1 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 gov.noaa.nmfs.inport:48104 Anne Ball 2017-11-14T14:15:21 SysAdmin InPortAdmin 2025-05-15T19:16:04 2017-11-16 Office for Coastal Management OCM 1002 Public No No 2017-11-16 1 Year 2018-11-16