Identification_Information: Citation: Citation_Information: Originator: U.S. Geological Survey (USGS), Pacific Coastal and Marine Science Center (PCMSC), Santa Cruz, CA. Publication_Date: 2014 Title: Polygon shapefile outlining the region where we experienced Inertial Measurement Unit (IMU) problems during the October 2011 survey. Geospatial_Data_Presentation_Form: vector Larger_Work_Citation: Citation_Information: Originator: U.S. Geological Survey (USGS), Pacific Coastal and Marine Science Center (PCMSC), Santa Cruz, CA. Publication_Date: 2014 Title: Bathymetry and Digital Elevation Models of Coyote Creek and Alviso Slough, South San Francisco Bay, California (Version 2, Revised March 2014) Edition: Version 2.0 Series_Information: Series_Name: U.S. Geological Survey Open-File Report Issue_Identification: OF2011-1315 Online_Linkage: http://pubs.usgs.gov/of/2011/1315, http://dx.doi.org/10.3133/ofr20111315 Description: Abstract: A GIS polygon shapefile outlining the region where we experienced IMU problems during the October 2011 survey. It was determined during the October 2011 survey that the configuration offset between the IMU and the primary GPS antenna was accidentally inverted during the first four days of surveying. As a result, the IMU was unable to properly calibrate its position. Fortunately, eight tie lines were collected throughout the western and eastern tidal flats during the last three days of this survey when the IMU was functioning properly. The extensive coverage of the tie lines enabled us to evaluate offsets due to the IMU problems and shoal the survey lines by the appropriate amount (varying from 8 to 33 cm) to minimize offsets. After performing these corrections the mean difference between tie line intersections dropped to 2 cm (SD = 3). Although our best effort was made to correct these data, the accuracy of elevations within these polygons is less reliable than for the remainder of these datasets. Purpose: To delineate regions within the survey with less reliable elevation values. Supplemental_Information: USGS Field Activity S-10-11-SF Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20111024 Ending_Date: 20111030 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -122.060187436 East_Bounding_Coordinate: -121.974560855 North_Bounding_Coordinate: 37.4706742088 South_Bounding_Coordinate: 37.4231662547 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: elevation Theme_Keyword: geoscientificInformation Theme_Keyword: inlandWaters Theme_Keyword: oceans Theme: Theme_Keyword_Thesaurus: GCMD SCIENCE PARAMETERS Theme_Keyword: OCEANS > BATHYMETRY > SEAFLOOR TOPOGRAPHY > BATHYMETRY Theme: Theme_Keyword_Thesaurus: GCMD INSTRUMENT PARAMETERS Theme_Keyword: SIDE-SCAN SONAR Theme_Keyword: GPS > Global Positioning System Theme_Keyword: LIDAR > Light Detection and Ranging Place: Place_Keyword_Thesaurus: Geographic Names Information System (GNIS) Place_Keyword: State of California Place_Keyword: San Francisco Bay Place_Keyword: Alameda County Place_Keyword: Santa Clara County Place_Keyword: Alviso Place_Keyword: Coyote Creek Place_Keyword: Alviso Slough Place_Keyword: Guadalupe Slough Access_Constraints: If physical samples or materials are available, constraints on their on-site access are described in "WR CMG Sample Distribution Policy" at URL: http://walrus.wr.usgs.gov/infobank/programs/html/main/sample-dist-policy.html Use_Constraints: This information is not intended for navigational purposes. Read and fully comprehend the metadata prior to data use. Uses of these data should not violate the spatial resolution of the data. Where these data are used in combination with other data of different resolution, the resolution of the combined output will be limited by the lowest resolution of all the data. Acknowledge the U.S. Geological Survey in products derived from these data. Share data products developed using these data with the U.S. Geological Survey. This database has been approved for release and publication by the Director of the USGS. Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use. Although this Federal Geographic Data Committee-compliant metadata file is intended to document these data in nonproprietary form, as well as in ArcInfo format, this metadata file may include some ArcInfo-specific terminology. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: USGS Pacific Coastal and Marine Science Center Contact_Person: David P Finlayson Contact_Position: Operational Geologist Contact_Address: Address_Type: physical address Address: 400 Natural Bridges Drive City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Country: USA Contact_Voice_Telephone: (831) 460-7557 Contact_Facsimile_Telephone: (831) 427-4748 Contact_Electronic_Mail_Address: dfinlayson@usgs.gov Browse_Graphic: Browse_Graphic_File_Name: Browse_Graphic_File_Description: Image showing S-10-11-SF survey tracklines. Browse_Graphic_File_Type: JPEG Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: This bathymetric data has not been independently verified for accuracy. Logical_Consistency_Report: All bathymetric values are derived from the same instruments and processing workflow. Completeness_Report: The raw bathymetry data was filtered in SEA Swath Processor and imported into CARIS HIPS and SIPS for post-processing. Within CARIS a swath angle BASE (Bathymetric with Associated Statistical Error) surface was created at 1 m resolution and the subset editor used to manually eliminate any remaining outliers or artifacts. The average depth within each 1 by 1 m cell was exported as an ASCII text file and imported into Surfer for interpolation using a linear kriging algorithm with a 1-simga nugget of 0.05 m and a 2 by 2 m search radius. The resultant grid was exported to ESRI ArcMap software for display. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Uncertainty in the horizontal position of each sounding is a function of the total uncertainty propagated through each of the following component instruments: 1) base station GPS, 2) vessel GPS, 3) intertial motion unit (IMU), 4) water sound velocity model, and 5) beam spreading in the water column. Assuming no systematic errors in the measurement instruments themselves, beam spreading is the dominate source of positional uncertainty. The 1-degree sonar beam of the SWATHplus-M results in horizontal uncertainty ranging from 0.10 m at 10 m slant range, to about 0.45 m at 50 m slant range. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: After filtering the data to remove obvious outliers, the standard deviation of the remaining sounding elevations was calculated for each 1 m by 1 m cell (each containing 19 soundings on average) in CARIS. The mean of the standard deviation for all cells in the survey is 0.05 m and 97% of the cells in the data set have a standard deviation of less than 0.15 m. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey, Coastal and Marine Geology Program Publication_Date: 2011 Title: USGS CMG Field Activity S-10-11-SF Geospatial_Data_Presentation_Form: raster digital data Online_Linkage: Type_of_Source_Media: online Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20111024 Ending_Date: 20111030 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: S-10-11-SF Source_Contribution: This 2011 field activity collected bathymetric data in San Francisco Bay. Process_Step: Process_Description: Sonar Data Collection The bathymetric surveys were conducted using a 234.5 kHz SEA (Systems Engineering & Assessment Ltd) SWATHplus-M phase-differencing sidescan sonar. The sonar was pole-mounted on the 34-foot USGS mapping vessel R/V Parke Snavely, and affixed to a hull brace. Real-time kinematic (RTK) GPS position data were passed through a CodaOctopus F180 intertial measurement unit (IMU) to the sonar hardware and data collection software. Sonar heads, GPS antennae, and the IMU were surveyed in place to a common reference frame with a Geodimeter 640 Total Station. The R/V Snavely was outfitted with three networked workstations and a navigation computer for use by the captain and survey crew for data collection and initial processing. Process_Date: 2011 Process_Step: Process_Description: Geodetic Control Geodetic control for the survey was established using a shore based Global Positioning System (GPS) base station broadcasting Real Time Kinematic (RTK) corrections to the survey vessel via UHF radio link. The base station was located at Moffett Naval Air Station, on a pre-existing benchmark identified as ARC 34. The NGS lists this monument as PID DG6881 (See Appendix A in report for NGS Datasheet). GPS base station coordinates: Reference Frame: NAD83 (NSRS2007) Epoch Date: 2007.00 Latitude: N 37 degrees 25' 34.57880" Longitude: W 122 degrees 02' 05.53373" Orthometric Height: 1.280 m (NAVD88 height modernization project elevation) Process_Date: 2011 Process_Step: Process_Description: Vessel Position and Attitude The R/V Snavely was equipped with a CodaOctopus F180 attitude and positioning system for the duration of the survey. The F180 is running F190 firmware, and receives real-time kinematic (RTK) corrections directly. The RTK GPS data (2 cm error ellipse) are combined with the inertial motion measurements directly within the F190 hardware so that high-precision position and attitude corrections are fed in real-time to the sonar acquisition equipment. The NAD83 (NSRS2007) Epoch 20007.00 3-dimensional reference frame was used for all data acquisition. Process_Date: 2011 Process_Step: Process_Description: Sound Velocity Measurements Sound velocity measurements were collected continuously with an Applied Micro Systems Micro SV deployed on the transducer frame for real-time sound velocity adjustments at the transducer-water interface. The Micro SV is accurate to +/- 0.03 m/s. In addition, sound velocity profiles (SVP) were collected with an Applied Micro Systems, SvPlus 3472. This instrument provides time-of-flight sound-velocity measurements by using invar rods with a sound-velocity accuracy of +/- 0.06 m/s, pressure measured by a semiconductor bridge strain gauge to an accuracy of 0.15 percent (Full Scale) and temperature measured by thermistor to an accuracy of 0.05 degrees Celsius (Applied Microsystems Ltd., 2005). Process_Date: 2011 Process_Step: Process_Description: Sonar Sounding Processing GPS data and measurements of vessel motion are combined in the F180 hardware to produce a high-precision vessel attitude packet. This packet is transmitted to the Swath Processor acquisition software in real-time and combined with instantaneous sound velocity measurements at the transducer head before each ping. Up to 20 pings per second are transmitted with each ping consisting of 2048 samples per side (port and starboard). The returned samples are projected to the seafloor using a ray-tracing algorithm working with the previously measured sound velocity profiles in SEA Swath Processor (version 3.05.18.04). A series of statistical filters are applied to the raw samples that isolate the seafloor returns from other uninteresting targets in the water column. Finally, the processed data is stored line-by-line in both raw (.sxr) and processed (.sxp) trackline files. Processed (.sxp) files were further processed with sxpegn (build 151) by Amy Foxgrover (USGS) to remove erroneous data from the files and make valid gain-normalized amplitude data for processing backscatter data. Process_Date: 2011 Process_Step: Process_Description: Digital Elevation Model Production The raw bathymetry data was filtered in SEA Swath Processor and imported into CARIS HIPS and SIPS for post-processing. Within CARIS a swath angle BASE (Bathymetric with Associated Statistical Error) surface was created at 1 m resolution and the subset editor used to manually eliminate any remaining outliers or artifacts. The average depth within each 1 by 1 m cell was exported as an ASCII text file and imported into Surfer for interpolation using a linear kriging algorithm with a 1-simga nugget of 0.05 m and a 2 by 2 m search radius. The resultant grid was exported to ESRI ArcMap software for display and further analyses. The entire survey was deepened by 6 cm to account for a bias resulting from changes in the boat instrumentation configuration that occured since the initial survey was collected in 2010. Process_Date: 2011 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Vector Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: G-polygon Point_and_Vector_Object_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: 10 Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.9996 Longitude_of_Central_Meridian: -123 Latitude_of_Projection_Origin: 0.0 False_Easting: 500000 False_Northing: 0.0 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: row and column Coordinate_Representation: Abscissa_Resolution: 1.0 Ordinate_Resolution: 1.0 Planar_Distance_Units: meters Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1983 (NSRS2007) Ellipsoid_Name: Geodetic Reference System 80 Semi-major_Axis: 6378137 Denominator_of_Flattening_Ratio: 298.257 Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey, Pacific Coastal and Marine Science Center (PCMSC) Contact_Person: David P Finlayson Contact_Address: Address_Type: mailing and physical address Address: 400 Natural Bridges Drive City: Santa Cruz State_or_Province: CA Postal_Code: 95060-5792 Country: US Contact_Voice_Telephone: 831-460-7557 Contact_Facsimile_Telephone: 831-427-4748 Contact_Electronic_Mail_Address: dfinlayson@usgs.gov Resource_Description: Downloadable Data Distribution_Liability: This information is not intended for navigational purposes. This database has been approved for release and publication by the Director of the USGS. Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: ESRI ASCII Grid Format_Version_Number: 1.0 Format_Information_Content: The ASCII file consists of header information containing a set of keywords, followed by cell values in row-major order. The file format is: > > > > > > >{NODATA_VALUE xxx} >row 1 >row 2 >. >. >. >row n > where xxx is a number, and the keyword nodata_value is optional and defaults to -9999. Row 1 of the data is at the top of the grid, row 2 is just under row 1 and so on. The nodata_value is the value in the ASCII file to be assigned to those cells whose true value is unknown. In the grid they will be assigned the keyword NODATA. Cell values are be delimited by spaces. No carriage returns are necessary at the end of each row in the grid (although they are included in this case). The number of columns in the header is used to determine when a new row begins. The number of cell values is equal to the number of rows times the number of columns. Transfer_Size: 30 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://pubs.usgs.gov/of/2011/1315/, http://dx.doi.org/10.3133/ofr20111315 Fees: No cost Metadata_Reference_Information: Metadata_Date: 2015 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Amy Foxgrover Contact_Address: Address_Type: mailing address Address: 400 Natural Bridges Drive City: Santa Cruz State_or_Province: California Postal_Code: 95060 Country: USA Contact_Voice_Telephone: (831) 460-7561 Contact_Electronic_Mail_Address: afoxgrover@usgs.gov Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998