Identification_Information: Citation: Citation_Information: Originator: VeeAnn A. Cross Publication_Date: 2010 Title: POTO_AREA: ESRI Format Binary Grid of the Merged Bathymetry and Elevation Data from the Potomac River/Chesapeake Bay Area For Use With USGS Cruise 06018 Geospatial_Data_Presentation_Form: raster digital data Series_Information: Series_Name: Open-File Report Issue_Identification: 2009-1151 Publication_Information: Publication_Place: Woods Hole Coastal and Marine Science Center, Woods Hole, MA Publisher: U.S. Geological Survey, Coastal and Marine Geology Program Online_Linkage: http://pubs.usgs.gov/of/2009/1151/data/basemap/elevation/poto_area.zip Online_Linkage: http://pubs.usgs.gov/of/2009/1151/html/catalog.html Larger_Work_Citation: Citation_Information: Originator: VeeAnn A. Cross Originator: David S. Foster Originator: John F. Bratton Publication_Date: 2010 Title: Continuous Resistivity Profiling and Seismic-Reflection Data Collected in 2006 from the Potomac River Estuary, Virginia and Maryland Series_Information: Series_Name: Open-File Report Issue_Identification: 2009-1151 Publication_Information: Publication_Place: Woods Hole Coastal and Marine Science Center, Woods Hole, MA Publisher: U.S. Geological Survey, Coastal and Marine Geology Program Online_Linkage: http://pubs.usgs.gov/of/2009/1151/ Description: Abstract: In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on Chesapeake Bay and the Potomac River Estuary in September 2006. Chesapeake Bay resource managers are concerned about nutrients that are entering the estuary via submarine groundwater discharge, which are contributing to eutrophication. The USGS has performed many related studies in recent years to provide managers with information necessary to make informed decisions about this issue. The research carried out as part of the study described here was designed to help refine nutrient budgets for Chesapeake Bay by characterizing submarine groundwater flow and discharge of groundwater beneath part of the mainstem and a major tributary, the Potomac River Estuary. Purpose: The purpose of this dataset is to provide a seamless elevation/bathymetry grid as a basemap layer for the work in the Potomac River area. Time_Period_of_Content: Time_Period_Information: Multiple_Dates/Times: Single_Date/Time: Calendar_Date: 1998 Single_Date/Time: Calendar_Date: 1999 Currentness_Reference: Publication data of the original source datasets Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -77.387222 East_Bounding_Coordinate: -75.604370 North_Bounding_Coordinate: 38.729651 South_Bounding_Coordinate: 37.706801 Keywords: Theme: Theme_Keyword_Thesaurus: General Theme_Keyword: U.S. Geological Survey Theme_Keyword: USGS Theme_Keyword: Coastal and Marine Geology Program Theme_Keyword: CMGP Theme_Keyword: Woods Hole Coastal and Marine Science Center Theme_Keyword: WHCMSC Theme_Keyword: Info Bank ID K-1-06-CH Theme_Keyword: bathymetry Theme_Keyword: NOAA's Ocean Service, Special Projects Theme_Keyword: hydrographic survey Theme_Keyword: estuary Theme_Keyword: estuarine bathymetry Theme_Keyword: elevation Theme_Keyword: digital elevation model Theme_Keyword: DEM Theme_Keyword: raster Theme_Keyword: National Elevation Dataset Theme_Keyword: NED Theme_Keyword: ESRI binary grid Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: inlandWaters Theme_Keyword: oceans Theme_Keyword: oceans and estuaries Theme_Keyword: oceans and coastal Theme_Keyword: imageryBaseMapsEarthCover Theme_Keyword: elevation Place: Place_Keyword_Thesaurus: General Place_Keyword: North America Place_Keyword: North Atlantic Place_Keyword: United States Place_Keyword: Virginia Place_Keyword: Potomac River Estuary Place_Keyword: Chesapeake Bay Place_Keyword: Maryland Access_Constraints: None. Use_Constraints: The public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey and the National Oceanic and Atmospheric Administration (NOAA) National Ocean Service (NOS) as the originators of the individual datasets. These data are not to be used for navigation. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: VeeAnn A. Cross Contact_Organization: U.S. Geological Survey Contact_Position: Marine Geologist Contact_Address: Address_Type: mailing and physical address Address: Woods Hole Coastal and Marine Science Center Address: 384 Woods Hole Rd. City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: (508) 548-8700 x2251 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: vatnipp@usgs.gov Browse_Graphic: Browse_Graphic_File_Name: http://pubs.usgs.gov/of/2009/1151/data/basemap/elevation/poto_area.gif Browse_Graphic_File_Description: Thumbnail image of the color coded relief in the Potomac River Estuary area. Browse_Graphic_File_Type: GIF Native_Data_Set_Environment: Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 9.2.6.1500 Cross_Reference: Citation_Information: Originator: Department of Commerce (DOC), National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), Special Projects (SP) Publication_Date: 1998 Title: Chesapeake Bay, VA/MD (M130) Bathymetric Digital Elevation Model (30 meter resolution) Derived From Source Hydrographic Survey Soundings Collected by NOAA Geospatial_Data_Presentation_Form: raster digital data Publication_Information: Publication_Place: Silver Spring, MD Publisher: NOAA's Ocean Service, Special Projects (SP) Online_Linkage: http://estuarinebathymetry.noaa.gov/ Cross_Reference: Citation_Information: Originator: U.S. Geological Survey (USGS), EROS Data Center Publication_Date: 1999 Title: National Elevation Dataset Geospatial_Data_Presentation_Form: raster digital data Publication_Information: Publication_Place: Sioux Falls, SD Publisher: U.S. Geological Survey Online_Linkage: http://ned.usgs.gov/ Online_Linkage: http://seamless.usgs.gov/ Data_Quality_Information: Completeness_Report: This dataset represent complete elevation information for the area of interest. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: This grid is a combination of two dataset that provide the best-available data for the land elevations and the bathymetry of Chesapeake Bay. The 7.5-minute elevation data for the conterminous United States are the primary initial source data for the land elevation and were acquired from the National Elevation Dataset (NED). The bathymetry dataset was acquired from the NOAA estuarine bathymetry website. This dataset was derived from two hundred ninety-seven surveys dating from 1850 to 1993. The NED website does not specify any value for horizontal accuracy. According to the metadata accompanying the bathymetry dataset, the horizontal accuracy is expressed as an estimated root mean square error (RMSE). The estimate of the RMSE is based upon horizontal accuracy tests of the source soundings used to generate the DEM. As a first approximation the locational accuracy of the source soundings are 0.0015 m at source "Smooth Sheet" scale (120 m @ 1:80,000 to 15 m @ 1:10,000). Smooth Sheets are maps generated as a principle product of each (historic) hydrographic survey with fully corrected soundings plotted on them. In both cases the user needs to refer to the original datasets to establish the details of the data and their estimates of accuracy. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: The metadata accompanying the NED dataset does not specify a vertical accuracy. However, the website indicates the vertical accuracy of the National Elevation Dataset (NED) varies spatially because of the variable quality of the source digital elevation models (DEMs). As such, the NED inherits the accuracy of the source DEMs. The most recently published figure of overall absolute vertical accuracy expressed as the root mean square error (RMSE) is 2.44 meters. The estuarine bathymetry metadata indicates the vertical RMSE statistic is used to describe the vertical accuracy of a DEM. It encompasses both random and systematic errors introduced during production of the data. The RMSE is encoded in element number 5 of record C of the DEM. This accuracy estimate includes components related to quantization of the source soundings (1.3 to 0.15 m), the systematic editing of the source data (1percentor 0.10m), un-sampled bathymetric features (estimated at less than 5percentof depth), time related changes (erosion, deposition, and seismic shifts), and dredging operations (cut and fill). It is estimated that the accuracy of the Bathymetric DEMs is 2 percent of depth or 1 meter for depths grater than 20 meters and 2 percentof depth or 0.20 meters for depths shallower than 20 meters. THESE DEMs SHOULD NOT BE USED FOR NAVIGATION. The two datasets used to create this merged product are referenced to different vertical datums. The NED data use a vertical datum of NAVD88 while the estuarine data simply specifies the vertical datum as referenced to the local tidal datum at the time of the hydrographic survey. No adjustment was made to the individual datasets to attempt to eliminate this discrepancy. The user needs to refer to the original datasets to establish the details of the data and their estimates of accuracy. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey (USGS), EROS Data Center Publication_Date: 1999 Title: National Elevation Dataset Geospatial_Data_Presentation_Form: raster digital data Publication_Information: Publication_Place: Sioux Falls, SD Publisher: U.S. Geological Survey Online_Linkage: http://ned.usgs.gov/ Online_Linkage: http://seamless.usgs.gov/ Type_of_Source_Media: online Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1999 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: NED Source_Contribution: Land elevation values. Source_Information: Source_Citation: Citation_Information: Originator: Department of Commerce (DOC), National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), Special Projects (SP) Publication_Date: 1998 Title: Chesapeake Bay, VA/MD (M130) Bathymetric Digital Elevation Model (30 meter resolution) Derived From Source Hydrographic Survey Soundings Collected by NOAA Geospatial_Data_Presentation_Form: raster digital data Publication_Information: Publication_Place: Silver Spring, MD Publisher: NOAA's Ocean Service, Special Projects (SP) Online_Linkage: http://estuarinebathymetry.noaa.gov/ Type_of_Source_Media: online Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1998 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: EstuaryBathy Source_Contribution: Bathymetry values. Process_Step: Process_Description: In generating a grid for the area of interest, this required four files to be downloaded from the National Elevation Dataset (NED) site (http://ned.usgs.gov/ or http://seamless.usgs.gov/). The downloaded files were each accompanied by metadata that indicates the publication date of the data as 1999. These original grids are in a geographic coordinate system, NAD83, with a vertical datum of NAVD88. The cell size of these grids is 0.000278 decimal degrees. These files cover the land portion of the area of interest. The cell values where water occurs is usually set to 0 - not true elevation (bathymetry) values. This process step, as well as all subsequent process steps were performed by the same individual - VeeAnn A. Cross. Process_Date: 2006 Source_Produced_Citation_Abbreviation: ned_47818044 Source_Produced_Citation_Abbreviation: ned_52341366 Source_Produced_Citation_Abbreviation: ned_77859792 Source_Produced_Citation_Abbreviation: ned_84386099 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: VeeAnn A. Cross Contact_Organization: U.S. Geological Survey Contact_Position: Marine Geologist Contact_Address: Address_Type: mailing and physical address Address: Woods Hole Coastal and Marine Science Center Address: 384 Woods Hole Rd. City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: (508) 548-8700 x2251 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: vatnipp@usgs.gov Process_Step: Process_Description: Using ArcMap 9.0, Spatial Analyst - Spatial Analyst Toolbar - Raster Calculator I merged all four of these grids together. The raster calculator command was: merge([ned_47818044], [ned_52341366], [ned_77859792], [ned_84386099]). This adds a temporary grid to the ArcMap table of contents. Right mouse click on the layer - Data - Make Permanent to convert the temporary grid to a permanent grid - merge4. Source_Used_Citation_Abbreviation: ned_47818044 Source_Used_Citation_Abbreviation: ned_52341366 Source_Used_Citation_Abbreviation: ned_77859792 Source_Used_Citation_Abbreviation: ned_84386099 Process_Date: 2006 Source_Produced_Citation_Abbreviation: merge4 Process_Step: Process_Description: ArcMap 9.0 - ArcToolbox - Data Management Tools - Projections and Transformations - Raster - Project Raster to project the original geographic grid to UTM, Zone 18, NAD83 using the bilinear interpolation. Because both the input and output grids are NAD83, no datum transformation was necessary. All other parameters were left to their default. Source_Used_Citation_Abbreviation: merge4 Process_Date: 2006 Source_Produced_Citation_Abbreviation: merge4_utm Process_Step: Process_Description: For the bathymetry portion of the area of interest, the Estuarine Bathymetry project of NOAA provided the data - http://estuarinebathymetry.noaa.gov/. To cover the whole Chesapeake Bay area, three data files were downloaded: M130_37076C5_BIG1.dem, M130_38076D4_BIG2.dem, and M130_39076C2_BIG3.dem. These files were accompanied by metadata indicating the publication date for these data as 1998. In addition, a complete explanation of their processing history is included. The original projection of the data is UTM, zone 18, NAD27 with a cell size of 30 meters. The vertical datum for the bathymetry is referenced to local tidal datum at the time of the hydrographic surveys that make up the dataset. The vertical unit is meters. Process_Date: 2006 Source_Produced_Citation_Abbreviation: M130_37076C5_BIG1.dem Source_Produced_Citation_Abbreviation: M130_38076D4_BIG2.dem Source_Produced_Citation_Abbreviation: M130_39076C2_BIG3.dem Process_Step: Process_Description: The Digital Elevation Model (DEM) estuarine files needed to be converted from the USGS DEM format to ESRI grid format. To do that, ArcMap 9.0 - ArcToolbox - Conversion Tools - To Raster - DEM to Raster. The output data type is float, with the Z-factor left to the default value of 1. Source_Used_Citation_Abbreviation: M130_37076C5_BIG1.dem Source_Used_Citation_Abbreviation: M130_38076D4_BIG2.dem Source_Used_Citation_Abbreviation: M130_39076C2_BIG3.dem Process_Date: 2006 Source_Produced_Citation_Abbreviation: big1 Source_Produced_Citation_Abbreviation: big2 Source_Produced_Citation_Abbreviation: big3 Process_Step: Process_Description: These grids then needed to be projected to UTM, Zone 18, NAD83 - basically just a datum transformation. To do this, ArcMap 9.0 - Data Management Tools - Projections and Transformations - Raster - Project Raster. The geographic transformation used was NAD_1927_to NAD_1980_NADCON. The resampling method was bilinear. Source_Used_Citation_Abbreviation: big1 Source_Used_Citation_Abbreviation: big2 Source_Used_Citation_Abbreviation: big3 Process_Date: 2006 Source_Produced_Citation_Abbreviation: big1_nad83 Source_Produced_Citation_Abbreviation: big2_nad83 Source_Produced_Citation_Abbreviation: big3_nad83 Process_Step: Process_Description: To combine the land and the bathymetry used ArcMap 9.0 - Spatial Analyst Toolbar - Raster Calculator. Using the Merge command within raster calculator: merge(big1_nad83, big2_nad83, big3_nad83, merge4_utm). The order of the file inputs is important, as the last raster listed has the lowest priority. In this case, the land grid (merge4_utm) needed to be last so that the true bathymetry values overwrote the zero values of the water areas in the land grid. The result of this merge command generated a temporary grid in the ArcMap table of contents. Source_Used_Citation_Abbreviation: big1_nad83 Source_Used_Citation_Abbreviation: big2_nad83 Source_Used_Citation_Abbreviation: big3_nad83 Source_Used_Citation_Abbreviation: merge4_utm Process_Date: 2006 Source_Produced_Citation_Abbreviation: temporary grid Process_Step: Process_Description: A graphic polygon was drawn indicating the area of interest. VACExtras 1.95 (a Woods Hole extension to ArcMap) was then used to clip the temporary merged grid with the polygon graphic using Clip Grid with Graphic. This in turn created a temporary grid that was then converted to a permanent file by right-clicking on the layer in the table of contents - Data - Make Permanent. Source_Used_Citation_Abbreviation: temporary grid Process_Date: 2006 Source_Produced_Citation_Abbreviation: poto_area Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Grid Cell Row_Count: 3702 Column_Count: 5144 Vertical_Count: 1 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Grid_Coordinate_System: Grid_Coordinate_System_Name: Universal Transverse Mercator Universal_Transverse_Mercator: UTM_Zone_Number: 18 Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.999600 Longitude_of_Central_Meridian: -75.000000 Latitude_of_Projection_Origin: 0.000000 False_Easting: 500000.000000 False_Northing: 0.000000 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: row and column Coordinate_Representation: Abscissa_Resolution: 30.000000 Ordinate_Resolution: 30.000000 Planar_Distance_Units: meters Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1983 Ellipsoid_Name: Geodetic Reference System 80 Semi-major_Axis: 6378137.000000 Denominator_of_Flattening_Ratio: 298.257222 Vertical_Coordinate_System_Definition: Altitude_System_Definition: Altitude_Datum_Name: North American Vertical Datum of 1988 Altitude_Resolution: 1 Altitude_Distance_Units: meters Altitude_Encoding_Method: Explicit elevation coordinate included with horizontal coordinates Depth_System_Definition: Depth_Datum_Name: referenced to local tidal datum at the time of the hydrographic survey Depth_Resolution: 1 Depth_Distance_Units: meters Depth_Encoding_Method: Explicit depth coordinate included with horizontal coordinates Distribution_Information: Distributor: Contact_Information: Contact_Person_Primary: Contact_Person: VeeAnn A. Cross Contact_Organization: U.S. Geological Survey Contact_Position: Marine Geologist Contact_Address: Address_Type: mailing and physical address Address: Woods Hole Coastal and Marine Science Center Address: 384 Woods Hole Rd. City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: (508) 548-8700 x2251 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: vatnipp@usgs.gov Resource_Description: Downloadable Data Distribution_Liability: Neither the U.S. government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: WinZip Format_Version_Number: 9.0 Format_Information_Content: This WinZip file contains the ESRI binary grid and an ESRI lyr file that can be used to display the data in ArcMap. In addition, the WinZip file has the associated metadata files. Transfer_Size: 60.7 MB Digital_Transfer_Option: Offline_Option: Offline_Media: DVD Recording_Capacity: Recording_Density: 4.75 Recording_Density_Units: GBytes Recording_Format: UDF Fees: None. Technical_Prerequisites: This WinZip file contains data available in ESRI binary grid format. The user must have software capable of uncompressing the WinZip file and reading/displaying the raster data. Metadata_Reference_Information: Metadata_Date: 20100325 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: VeeAnn A. Cross Contact_Organization: U.S. Geological Survey Contact_Position: Marine Geologist Contact_Address: Address_Type: mailing and physical address Address: Woods Hole Coastal and Marine Science Center Address: 384 Woods Hole Rd. City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: (508) 548-8700 x2251 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: vatnipp@usgs.gov Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Time_Convention: local time Metadata_Extensions: Online_Linkage: http://www.esri.com/metadata/esriprof80.html Profile_Name: ESRI Metadata Profile