Identification_Information: Citation: Citation_Information: Originator: Roberto J. Anima Originator: John L. Chin Originator: David P. Finlayson Originator: Mary L. McGann Originator: Florence L. Wong Publication_Date: 2007 Title: 4-m resolution bathymetric grid of Tomales Bay, California (TOMALESG) Edition: Version 1.0, September 19, 2007 Geospatial_Data_Presentation_Form: map Series_Information: Series_Name: USGS Open-File Report Issue_Identification: USGS OFR 2007-xxxx Publication_Information: Publication_Place: Menlo Park, California Publisher: U.S. Geological Survey Online_Linkage: Description: Abstract: The Tomales Bay bathymetry Digital Elevation Model (DEM) is composed of data from three bathymetric surveys collected between November 2004 and August 2006 (USGS activities F-1-04-TB, F-2-05-TB, B-1-06-TB). During the 2004 and 2005 surveys, the northern and central bay bathymetry was collected using an interferometric sidescan system. In 2006, the shoal tidelands in the southern portion of the bay were surveyed using a single-beam echo sounder. The final data set described in this report is a composite of these three surveys. This metadata record describes the Tomales Bay grid exported as 1. ESRI ASCII grid format (includes nodata -9999 values) > ncols 3172 > nrows 3959 > xllcorner 501413.013329 > yllcorner 4216501.279255 > cellsize 4 > NODATA_value -9999 > -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 > -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 > -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 > -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 > -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 > -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 > -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 > -9999 -9999 -5.298165 -4.233628 -9999 -9999 -9999 > -9999 -9999 -9999 -9999 -9999 - 2. x-y (decimal degrees) and z (elevations in meters) data (nodata excluded). > -122.98086,38.23902,-5.298 > -122.98082,38.23902,-4.234 > -122.98090,38.23898,-5.162 > -122.98086,38.23898,-5.997 Purpose: These data are intended for science researchers, students, policy makers, and the general public. The data can be used with geographic information systems (GIS) software to display geologic and oceanographic information. Supplemental_Information: Additional information about the field activities from which this data set was derived are available online at >http://walrus.wr.usgs.gov/infobank/f/f104tb/html/f-1-04-tb.meta.html >http://walrus.wr.usgs.gov/infobank/f/f205tb/html/f-2-05-tb.meta.html >http://walrus.wr.usgs.gov/infobank/b/b106tb/html/b-1-06-tb.meta.html Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as in ArcInfo format, this metadata file may include some ArcInfo-specific terminology. Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2006 Currentness_Reference: Ground Condition Status: Progress: Complete Maintenance_and_Update_Frequency: None Planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -122.98388487 East_Bounding_Coordinate: -122.83886718 North_Bounding_Coordinate: 38.23903649 South_Bounding_Coordinate: 38.09620335 Keywords: Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: coastal geology Theme_Keyword: bathymetry Theme_Keyword: sidescan Theme_Keyword: interferometric sidescan Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: environment Theme_Keyword: geoscientificInformation Theme_Keyword: oceans Place: Place_Keyword_Thesaurus: Geographic Names Information System Place_Keyword: Tomales Bay, California Place_Keyword: Inverness Ridge, California Place_Keyword: San Andreas Fault, California Place_Keyword: Avalis Beach, California Place_Keyword: Lawsens Landing, California Place_Keyword: Pelican Point, California Place_Keyword: Blakes Landing, California Place_Keyword: Marconi, California Place_Keyword: Hearts Desire Beach, California Place_Keyword: Millerton Point, California Place_Keyword: Inverness, California Place_Keyword: Lagunitas Creek, California Place_Keyword: Toms Point, California Place_Keyword: White Gulch, California Place_Keyword: Tomales Beach, California Place_Keyword: Marshall Beach, California Place_Keyword: Lairds Landing, California Place_Keyword: Cypress Grove, California Place_Keyword: Reynolds, California Place_Keyword: California Place_Keyword: USA Place: Place_Keyword_Thesaurus: GEOnet Names Server Place_Keyword: north Pacific Ocean Access_Constraints: None Use_Constraints: These data are not to be used for navigation. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Florence L. Wong Contact_Organization: United States Geological Survey (USGS) Coastal and Marine Geology (CMG) Contact_Position: Geologist, GIS Coordinator Contact_Address: Address_Type: mailing and physical address Address: USGS, MailStop 999, 345 Middlefield Road City: Menlo Park State_or_Province: CA Postal_Code: 94025-3561 Country: USA Contact_Voice_Telephone: (650) 329-5327 Contact_Facsimile_Telephone: (650) 329-5190 Contact_Electronic_Mail_Address: fwong@usgs.gov Native_Data_Set_Environment: SunOS, 5.8, sun4u UNIX ArcInfo version 9.1 Browse_Graphic: Browse_Graphic_File_Name: http://pubs.usgs.gov/of/2008/1237/images/tomalesg.jpg Browse_Graphic_File_Description: preview image of report Browse_Graphic_File_Type: gif or jpg Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: The advertised accuracy of the SWATHplus system in shallow waters is better than IHO S44 Special Order, but a total propagation error model has not been developed for the USGS system used in these surveys so the true error in both position and elevation is unknown. Furthermore, no operational tide measurements were available for the survey so there is likely to be a spatially and temporally variable vertical error due to differences between the predicted tides and the water levels actually experienced during the survey. Finally, a comparison of grid elevations having overlapping coverage between the 2004 and 2005 surveys revealed a 1.44 m vertical offset (median of all overlapping cells). This error may be due to a mis-configuration of the F180 unit, but the exact cause of the error is unknown. In the final DEM, a static offset of +1.44 m was added to the 2004 data to minimize the vertical offset between the 2004 and 2005 data. No additional vertical error analysis has been performed on these data. Logical_Consistency_Report: Not applicable for raster data. Completeness_Report: See Attribute_Accuracy_Report. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: See Attribute_Accuracy_Report. Lineage: Process_Step: Process_Description: Swath bathymetry. Swath bathymetry for the northern and central portions of Tamales Bay (cruise F-1-04-TB and F-2-05-TB) were collected using a pole-mounted, SEA Inc., 234 kHz, SWATHplus interferometric sidescan sonar system. Attitude compensation and vessel positioning were provided by a CodaOctopus F180 attitude and positioning system. Sound velocity profile measurements were collected with an Applied Micro Systems, SvPlus 3472. The horizontal datum of the surveys was established by differential GPS using the WGS84 ellipsoid. The vertical datum of the surveys was based on Mean Lower Low Water (MLLW) predictions for Marshall, Tomales Bay, using the software Tides and Currents by Nobeltec. Raw bathymetry and amplitude data were collected using the Swath Processor software provided with the sonar system and gridded at 1 m resolution using the accompanying Grid Processor software package. These raster data were then exported to Fledermaus, edited and smoothed in that package and finally exported to ESRI ASCII Grid format using USGS in-house software. Process_Date: 2006 Process_Step: Process_Description: Single-Beam Bathymetry. Single-beam echo sounder data were collected over the shallow tidelands of southern Tomales Bay during August 2006 (cruise B-1-06-TB). A pole-mounted ESE50 Echo sounder with a co-located Real-time kinematic (RTK) GPS receiver system provided real-time vertical and horizontal positioning of the sonar transducer during operations. These data were reduced to positional soundings on the sea floor using HYPACK (version 6.2) with a 30-second averaging period (to remove heave), gridded into a 10-m resolution DEM using Surfer version 8.0, and exported to ESRI ASCII Grid format using USGS in-house software. The horizontal and vertical datum of the survey was established by the RTK GPS system as WGS84 and NAVD88, respectively. The error ellipse on the location of the GPS receivers is typically < 5 cm and this propagates through to the sea floor with RMS errors on sea bed elevation of < 10 cm. Process_Date: 2006 Process_Step: Process_Description: 4 m composite bathymetry. Each of the three surveys was resampled to a 4 m cell spacing using the Spline Smooth tool of Surfer 8. The swath bathymetry was converted from MLLW to NAVD88 vertical datum using VDatum (NOAA Office of the Coast Survey and National Geodetic Survey), and then the three surveys were blended together in ArcGIS using the MOSAIC TO NEW RASTER tool with the blend option. The final data set was trimmed to the convex hull of the survey data area. Process_Date: 2006 Process_Step: Process_Description: First draft of metadata created by florence using FGDCMETA.AML ver. 1.35 08/02/2000 on ArcInfo data set /we6/florence/cordell/tomales/covs/tomalesg Process_Date: 20070919 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Grid Cell Row_Count: 3959 Column_Count: 3172 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Grid_Coordinate_System: Grid_Coordinate_System_Name: Universal Transverse Mercator Universal_Transverse_Mercator: UTM_Zone_Number: 10 Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.9996 Longitude_of_Central_Meridian: -123.0 Latitude_of_Projection_Origin: 0.0 False_Easting: 500000 False_Northing: 0 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: 4.0 Ordinate_Resolution: 4.0 Planar_Distance_Units: Meters Geodetic_Model: Horizontal_Datum_Name: WGS84 Ellipsoid_Name: WGS84 Semi-major_Axis: 6378206.4 Denominator_of_Flattening_Ratio: 294.98 Entity_and_Attribute_Information: Overview_Description: Entity_and_Attribute_Overview: > >TOMALESG.STA: > >COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME > 1 MIN 8 15 F 3 > 9 MAX 8 15 F 3 > 17 MEAN 8 15 F 3 > 25 STDV 8 15 F 3 > > MIN MAX MEAN STDV > -19.150 0.668 -4.379 2.452 > Entity_and_Attribute_Detail_Citation: none Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: United States Geological Survey (USGS) Coastal and Marine Geology (CMG) Contact_Person: Florence L. Wong Contact_Position: Geologist, GIS Coordinator Contact_Address: Address_Type: mailing and physical address Address: USGS, MailStop 999, 345 Middlefield Road City: Menlo Park State_or_Province: CA Postal_Code: 94025-3561 Country: USA Contact_Voice_Telephone: (650) 329-5327 Contact_Facsimile_Telephone: (650) 329-5190 Contact_Electronic_Mail_Address: fwong@usgs.gov Resource_Description: USGS OFR 2007-xxx Distribution_Liability: Please recognize the U.S. Geological Survey (USGS) as the source of this information. Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: Compressed file including Arcinfo grid and metadata. Format_Version_Number: 9.2 Format_Specification: Arcinfo ASCII grid File_Decompression_Technique: windows winzip or unix gunzip Transfer_Size: 5 MB Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://pubs.usgs.gov/of/2008/1237/ Fees: none Metadata_Reference_Information: Metadata_Date: 20070919 Metadata_Review_Date: 200710 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: United States Geological Survey (USGS) Coastal and Marine Geology (CMG) Contact_Person: Florence L. Wong Contact_Position: Geologist, GIS Coordinator Contact_Address: Address_Type: mailing and physical address Address: USGS, MailStop 999, 345 Middlefield Road City: Menlo Park State_or_Province: CA Postal_Code: 94025-3561 Country: USA Contact_Voice_Telephone: (650) 329-5327 Contact_Facsimile_Telephone: (650) 329-5190 Contact_Electronic_Mail_Address: fwong@usgs.gov Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata ("CSDGM version 2") Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Access_Constraints: none Metadata_Use_Constraints: none