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3,672 results returned

  1. Title: Future Erosion, San Mateo County Sea Level Rise Vulnerability Assessment Project, 2008

    Contributors:

    Summary: This polygon shapefile represents the projected extent of coastal erosion expected with 4.6 feet of sea level rise. The points depicted represent the highest estimated 100 yr tide elevation for locations surrounding the San Francisco Bay. Source: Pacific Institute. Source Date: 2008. This layer is part of the San Mateo County Sea Level Rise Vulnerability Assessment Project. These data are intended for researchers, students, and policy makers for reference and mapping purposes, and may be used for basic applications such as viewing, querying, and map output production. County of San Mateo Information Services Department and Pacific Institute. (2019). Future Erosion, San Mateo County Sea Level Rise Vulnerability Assessment Project, 2008. County of San Mateo Information Services Department. Available at: http://purl.stanford.edu/qq750jp2957. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

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  2. Title: Map Of An Exploring Expedition To The Rocky Mountains in the Year 1842, Oregon & North California In The Years 1843-44. By Brevet Capt. J. C. Fremont Of The Corps Of Topographical Engineers Under the orders of Col. J.J. Abert, Chief Of The Topographical Bureau. Lith. by E. Weber & Co. Baltimore, Md (Raster Image)

    Contributors:

    Summary: The large map of the west is one of the most interesting and beautiful government maps of the 1840's. It filled in many of the gaps in cartographic knowledge of the west. Charles Preuss was the cartographer. Map is without color. Book is bound with full leather with "Executive Documents 2d Sess. 28th Cong." on the spine in gold. Appears in "Report of The Exploring Expedition to The Rocky Mountains in the Year 1842, and to Oregon and North California in the Years 1843-'44." The historic map layers in the Google Earth Rumsey Map Collection have been selected by David Rumsey from his large collection of historical maps, as well as some from other collections with which he collaborates. All the maps contain rich information about the past and represent a sampling of time periods, scales, and cartographic art, resulting in visual history stories that only old maps can tell. Each map has been georeferenced by Rumsey, thus creating unique digital map images that allow the old maps to appear in their correct places on the modern globe. Some of the maps fit perfectly in their modern spaces, while othersgenerally earlier period mapsreveal interesting geographical misconceptions of their time. Cultural features on the maps can be compared to the modern satellite views using the slider bars to adjust transparency. The result is an exploration of time as well as space, a marriage of historic cartographic masterpieces with innovative contemporary software tools.

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  3. Title: Climatic Map Of California. Published By The Southern Pacific Company. 1888. Compiled by E. McD. Johnstone, S.P. Co. From Map Prepared Under The Direction Of Brig. Gen. H.C. Wright, Chief Of Eng'rs. U.S.A. Lith H.S. Crocker & Co. S.F. Cal. Entered ... 1887, by the Southern Pacific Company ... Washington ... (Raster Image)

    Contributors:

    Summary: Second edition. Shows the different temperature zones of the state by use of color. Also used as a promotional broadside for the Southern Pacific Railroad. Above the map reads "If You Intend To Travel Take The "Sunset Route" Of The Southern Pacific Company." The historic map layers in the Google Earth Rumsey Map Collection have been selected by David Rumsey from his large collection of historical maps, as well as some from other collections with which he collaborates. All the maps contain rich information about the past and represent a sampling of time periods, scales, and cartographic art, resulting in visual history stories that only old maps can tell. Each map has been georeferenced by Rumsey, thus creating unique digital map images that allow the old maps to appear in their correct places on the modern globe. Some of the maps fit perfectly in their modern spaces, while othersgenerally earlier period mapsreveal interesting geographical misconceptions of their time. Cultural features on the maps can be compared to the modern satellite views using the slider bars to adjust transparency. The result is an exploration of time as well as space, a marriage of historic cartographic masterpieces with innovative contemporary software tools.

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  4. Title: San Francisco, California 1915 (Raster Image)

    Contributors:

    Summary: This layer is a georeferenced raster image of the historic paper map entitled: San Francisco and vicinity. It was published by Southern Pacific Company in 1915. Scale [ca. 1:30,800]. The image inside the map neatline is georeferenced to the surface of the earth and fit to the California Zone III State Plane Coordinate System NAD83 (in Feet) (Fipszone 0403). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as roads, railroads, street car routes, drainage, selected public buildings, parks, cemeteries, wharves, and more. Also shows the grounds of Panama-Pacific International Exposition. Relief is shown by hachures. Includes inset: San Francisco and adjacent territory. Also includes indexes to points of interest. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

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  5. Title: San Francisco and vicinity

    Contributors:

    Summary: Extent: 1 map Notes: Includes indexes and inset of "San Francisco and adjacent territory.". Text of "San Francisco, what to see, how to see it," map of "Southern Pacific and connections," and ill. on verso. Scale approximately 1:30,800

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  6. Title: Map of the United States showing the Texas & Pacific Railway and its connections, November, 1875

    Contributors:

    Summary: Relief shown by hachures.; In upper right margin: Map no. 2. 26 x 38 centimeters Scale not given General Map Collection

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  7. Title: Alaska and the routes of the Canadian Pacific Railway Company's British Columbia coast steamers

    Contributors:

    Summary: Relief shown by spot heights.; Annotated.; Rail and steamship lines of the Canadian Pacific Railway shown in red; other railroads and trails shown in black.; "Checked to Dec. 1923, C.P. Ry. Lines."; "A 6044." 43 x 76 centimeters Scale approximately 1:4,500,000 General Map Collection

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  8. Title: Map showing lands belonging to the Northern Pacific Railroad Co. in ... North Dakota

    Contributors:

    Summary: The shaded sections indicate Railroad Lands for sale. Map corrected to June 1st, 1893.; "Compiled and drawn by A.J. Pray." 86 x 67 centimeters No scale given. General Map Collection

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  9. Title: Map to accompany report of Gen. G.M. Dodge, Chief Engineer on the crossing of the Missouri River, 1867

    Contributors:

    Summary: 1 map

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  10. Title: Ocean Depths: California Coast, 2000

    Contributors:

    Summary: This point shapefile depicts ocean depths gridded on a 5-minute latitude/longitude interval. This coverage was created from data extracted from the National Oceanic and Atmospheric Administration (NOAA) National Geophysical Data Center (NGDC) "TerrainBase" dataset. The TerrainBase global digital terrain model contains a complete matrix of land elevation and ocean depth values for the entire world. NGDC/World Data Center-A developed the model using the best public domain data available at the time of publication. The intended use of this coverage is as a companion dataset to the Department of Fish and Wildlife "Trawl Logbook Catch Grid," developed by the Pacific Fishery Management Council, the States of Washington, Oregon and California, and the National Marine Fisheries Service (see coverage "caltrawl" in Resource Details Supplemental Information). The coarse resolution of the estimated depths facilitates rapid display on microcomputer and comparative analysis of trawl block data. These data are not suitable for inshore habitat analysis nor for navigation purposes. California Department of Fish and Wildlife. (2000). Ocean Depths: California Coast, 2000. Marine Region GIS Lab. Available at: http://purl.stanford.edu/gc081vs0264. Converted to California Teale Albers NAD83 by the California Department of Fish and Game --BEGIN ORIGINAL METADATA - THIS INFORMATION MAY NOT BE CURRENT-- Identification_Information: Citation: Citation_Information: Originator: National Oceanic and Atmospheric Administration Originator: California Department of Fish and Game Publication_Date: 199707 Title: NOAA 5-minute Gridded Sea Floor Elevations Geospatial_Data_Presentation_Form: vector digital data Online_Linkage: \\Molib01\GIS_Library\Elevation\Water\Points\calbath5 Description: Abstract: Calbath5 is a point dataset of ocean depths gridded on a 5-minute latitude/longitude interval. This dataset was created from data extracted from the NOAA National Geophysical Data Center (NGDC) "TerrainBase" dataset. The TerrainBase global digital terrain model contains a complete matrix of land elevation and ocean depth values for the entire world. Purpose: Assess California coastwide ocean depths. Supplemental_Information: Converted to California Teale Albers NAD83 by the California Department of Fish and Game -- BEGIN ORIGINAL METADATA - THIS INFORMATION MAY NOT BE CURRENT -- DEPARTMENT OF FISH AND GAME -- GIS METADATA NOAA 5-minute Gridded Sea Floor Elevations COVERAGE NAME: calbath5 COVERAGE PATH: dfghost /tsb/dfgbase/gislib METADATA FILE: calbath5.txt METADATA DATE: July 11, 1997 ------------------------- COVERAGE DESCRIPTION: Calbath5 is a point coverage of ocean depths gridded on a 5-minute latitude/longitude interval. This coverage was created from data extracted from the NOAA National Geophysical Data Center (NGDC) "TerrainBase" dataset. The TerrainBase global digital terrain model contains a complete matrix of land elevation and ocean depth values for the entire world. NGDC/WDC-A developed the model using the best public domain data available at the time of publication. The intended use of calbath5 is as a companion dataset to the Department of Fish and Game "Trawl logbook catch grid", developed by the Pacific Fishery Management Council, the States of Washington, Oregon, and California, and the National Marine Fisheries Service (see coverage "caltrawl"). The coarse resolution of the estimated depths facilitates rapid display on microcomputer and comparative analysis of trawl block data. This coverage is not suitable for inshore habitat analysis nor for navigation. PROCESSING STEPS 1. Internet accessed NOAA/NGDC site: http://www.ngdc.noaa.gov/mgg/global/seltopo.html 2. Entered min/max decimal degree lat/long values for coverage caltrawl, plus a 0.1 degree buffer. 3. Selected output options: TerrainBase, ascii,lon/lat/datavalue, comma-delimited, Least Sig.Byte 1st. 4. In ARCVIEW, added comma-delimited table and created a new event theme. 5. Converted event theme to shapefile. 6. Extracted points within extent of coverage "caltrawl", plus manually extended buffer. Re-converted to a new shapefile. 7. Edited attributes, added meters, feet, fathom units. Constants: 1 meter = 3.2808 feet; 1 fathom = 6 feet. 8. Removed grid anomolies where offshore values had non-negative data values, i.e. where ocean points had elevations greater than zero. 9. Ran spatial join, adding item BLOCK10_ID from coverage "caltrawl". 10.In ARC/INFO ran shapearc to convert shapefile to a coverage. 11.Reprojected decimal degree coverage to Teale albers, using default datum. (NOAA/NGDC datum unknown) VITAL STATISTICS: Standard Teale Parameters? [x] YES; [ ] NO Datum: NAD 27 Projection: Albers Units: Meters 1st Std. Parallel: 34 00 00 (34.0 degrees N) 2nd Std. Parallel: 40 30 00 (40.5 degrees N) Longitude of Origin: -120 00 00 (120.0 degrees W) Latitude of Origin: 00 00 00 (0.0 degrees N) False Easting (X shift): 0 False Northing (Y shift): -4,000,000 Source: U.S. DOC NOAA/National Geophysical Data Center URL http://www.ngdc.noaa.gov/mgg/global/seltopo.html Source Media: digital file Source Projection: unprojected, geographic latitude/longitude Source Units: decimal degrees, elevations in meters Source Scale: various Capture Method: event theme created from NOAA data Conversion Software: [ ] PC-ARC/INFO; [x] Workstation ARC/INFO [x] ARCVIEW Version: 7.x (HP-UX 10.x); ARCVIEW 3.0 Data Structure: vector ARC/INFO Coverage Type: point ARC/INFO Precision: single ARC/INFO Tolerances: fuzzy= 112.354m; dangle= 1.0 m Number of Features: points: 3036 File Size: appx. 760K, uncompressed arc export file: calbath5.e00 Data Updated: 1997.07.11 DATA DICTIONARY: Structure for CALBATH5.PAT COL ITEM NAME WIDTH TYPE N.DEC DESCRIPTION 1 AREA 4 F 3 ARC/INFO default 5 PERIMETER 4 F 3 ARC/INFO default 9 CALBATH5# 4 B - ARC/INFO default 13 CALBATH5-ID 4 B - ARC/INFO default 17 LON 4 F 2 Longitude, decimal degrees 21 LAT 4 F 2 Latitude, decimal degrees 25 DATAVALUE 4 B - Original NOAA value, depth in meters 29 METERS 4 B - Absolute value of DATAVALUE 33 FEET 8 F 0 Depth in feet 41 FATHOMS 4 B - Depth in fathoms 45 BLOCK10_ID 6 I - DFG Trawl Block Identifier Description of item (field) values: BLOCK10-ID ---- ID corresponding to the block number appearing in the "Washington-Oregon-California Trawl Logbook". Due to misalignment of grids, instances of BLOCK10-ID in this coverage are only appoximate. DATA QUALITY ASSESSMENT: A term to describe the type of height values represented in the model (such as mean, mode, point, etc.) cannot be assigned to the TerrainBase model since it is comprised of a variety of source data. The type of terrain height represented by these source data sets varies from one model to the next. For example, the FNOC model has modal heights, while the USA model uses point heights, and the Europe model has mean heights. Consequently, it is not possible to assign a single term to represent all of the height values given in the TerrainBase model. To satisfy interested users, however, a term that can be used which is common to all of the source data is best estimate of height. That is, the data represent the best estimate of height for each 5-minute cell. Although such a term has minimal scientific value, it does emphasize the fact that the data only represent reasonable estimates of the height of the terrain (NOAA/NGDC 1997). METADATA CONTACT: =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Paul Veisze, Spatial Data Coordinator California Department of Fish and Game Technical Services Branch -- GIS Unit 1730 I Street, Sacramento, CA 95814 Phone: 916-323-1667 \ Fax: 916-323-1431 ^---\-> Email: pveisze@dfg.ca.gov \ http://www.dfg.ca.gov =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= RESPONSIBILITY FOR DATA ACCURACY AND UPDATES: Topography/TerrainBase Technical data contact: Paula Dunbar, pdunbar@ngdc.noaa.gov. NOAA/NGDC Mail Code E/GC3, 325 Broadway Boulder, CO USA 80303. phone 303-497-3930, fax 303-497-6513 -- end of file calbath5.txt -- -- END ORIGINAL METADATA -- Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 199707 Currentness_Reference: publication date Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -126.008643 East_Bounding_Coordinate: -116.667519 North_Bounding_Coordinate: 42.292535 South_Bounding_Coordinate: 32.047396 Keywords: Theme: Theme_Keyword_Thesaurus: none Theme_Keyword: elevation Theme_Keyword: oceans Theme_Keyword: bathymetry Place: Place_Keyword_Thesaurus: none Place_Keyword: California Access_Constraints: none Use_Constraints: none Native_Data_Set_Environment: Microsoft Windows 2000 Version 5.0 (Build 2195) Service Pack 3; ESRI ArcCatalog 8.3.0.800 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Vector Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Entity point Point_and_Vector_Object_Count: 3036 SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Point Point_and_Vector_Object_Count: 4 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Map_Projection: Map_Projection_Name: Albers Conical Equal Area Albers_Conical_Equal_Area: Standard_Parallel: 34.000000 Standard_Parallel: 40.500000 Longitude_of_Central_Meridian: -120.000000 Latitude_of_Projection_Origin: 0.000000 False_Easting: 0.000000 False_Northing: -4000000.000000 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: 0.002048 Ordinate_Resolution: 0.002048 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 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: calbath5.pat Attribute: Attribute_Label: FID Attribute_Definition: Internal feature number. Attribute_Definition_Source: ESRI Attribute_Domain_Values: Unrepresentable_Domain: Sequential unique whole numbers that are automatically generated. Attribute: Attribute_Label: Shape Attribute_Definition: Feature geometry. Attribute_Definition_Source: ESRI Attribute_Domain_Values: Unrepresentable_Domain: Coordinates defining the features. Attribute: Attribute_Label: AREA Attribute_Definition: Area of feature in internal units squared. Attribute_Definition_Source: ESRI Attribute_Domain_Values: Unrepresentable_Domain: Area is always zero for point coverages. Values are automatically generated. Attribute: Attribute_Label: PERIMETER Attribute_Definition: Perimeter of feature in internal units. Attribute_Definition_Source: ESRI Attribute_Domain_Values: Unrepresentable_Domain: Perimeter is always zero for point coverages. Values are automatically generated. Attribute: Attribute_Label: CALBATH5# Attribute_Definition: Internal feature number. Attribute_Definition_Source: ESRI Attribute_Domain_Values: Unrepresentable_Domain: Sequential unique whole numbers that are automatically generated. Attribute: Attribute_Label: CALBATH5-ID Attribute_Definition: User-defined feature number. Attribute_Definition_Source: ESRI Attribute: Attribute_Label: LON Attribute: Attribute_Label: LAT Attribute: Attribute_Label: DATAVALUE Attribute: Attribute_Label: METERS Attribute: Attribute_Label: FEET Attribute: Attribute_Label: FATHOMS Attribute: Attribute_Label: BLOCK10_ID Distribution_Information: Resource_Description: Downloadable Data Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Transfer_Size: 0.396 Metadata_Reference_Information: Metadata_Date: 20030929 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: California Department of Fish and Game Contact_Person: GIS Service Center Contact_Address: Contact_Electronic_Mail_Address: geodata@dfg.ca.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 --END ORIGINAL METADATA-- This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

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  11. Title: Map of California illustrating its climatology, comparative area, rail lines, topography, etc., compiled from official and authentic sources

    Contributors:

    Summary: Relief shown by shading.; Shows rail lines, average temperatures, area in square miles.; Inset maps of Area and Average temperatures.; Index and text on verso. 64 x 52 centimeters Scale not given. General Map Collection

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  12. Title: Seafloor Character: Offshore of Refugio Beach, California, 2015

    Contributors:

    Summary: This layer is a georeferenced raster image containing seafloor character data for the offshore area of Refugio Beach, California. A map that show these data are published in Scientific Investigations Map 3319, "California State Waters Map Series--Offshore of Refugio Beach, California." This layer is part of USGS Data Series 781. In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP) to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats and geology within the 3-nautical-mile limit of California's State Waters. CSMP has divided coastal California into 110 map blocks, each to be published individually as United States Geological Survey Open-File Reports (OFRs) or Scientific Investigations Maps (SIMs) at a scale of 1:24,000. Maps display seafloor morphology and character, identify potential marine benthic habitats and illustrate both the seafloor geology and shallow (to about 100 m) subsurface geology. Data layers for bathymetry, bathymetric contours, acoustic backscatter, seafloor character, potential benthic habitat and offshore geology were created for each map block, as well as regional-scale data layers for sediment thickness, depth to transition, transgressive contours, isopachs, predicted distributions of benthic macro-invertebrates and visual observations of benthic habitat from video cruises over the entire state. These data are intended for science researchers, students, policy makers, and the general public. This information is not intended for navigational purposes.The data can be used with geographic information systems (GIS) software to display geologic and oceanographic information. Additionally, this coverage can provide a geologic map for the public and geoscience community to aid in assessments and mitigation of geologic hazards in the coastal region and sufficient geologic information for land-use and land-management decisions both onshore and offshore. This information is not intended for navigational purposes. Phillips, E.L., Erdey, M.D., Cochrane, G.R. (2015). Seafloor Character: Offshore of Refugio Beach, California, 2015. California State Waters Map Series Data Catalog: U.S. Geological Survey Data Series 781. Available at: http://purl.stanford.edu/tt733rj5282. Information for USGS Coastal and Marine Geology related activities are online at http://walrus.wr.usgs.gov/infobank/z/z206sc/html/z-2-06-sc.meta.html and http://walrus.wr.usgs.gov/infobank/z/z107sc/html/z-1-07-sc.meta.html This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

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  13. Title: Backscatter: Offshore of Refugio Beach, California, 2015

    Contributors:

    Summary: This layer is a georeferenced raster image containing acoustic-backscatter data for the offshore area of Refugio Beach, California. The acoustic-backscatter map of the area was generated from data collected by the U.S. Geological Survey (USGS). The USGS mapped this region in the summer 2008 using a 234.5 kHz SEA (AP) Ltd. SWATHplus-M phase-differencing sidescan sonar. These data were later re-processed in 2012. Within the acoustic-backscatter imagery, brighter tones indicate higher backscatter intensity, and darker tones indicate lower backscatter intensity. The intensity represents a complex interaction between the acoustic pulse and the seafloor, as well as characteristics within the shallow subsurface, providing a general indication of seafloor texture and sediment type. Backscatter intensity depends on the acoustic source level; the frequency used to image the seafloor; the grazing angle; the composition and character of the seafloor, including grain size, water content, bulk density, and seafloor roughness; and some biological cover. Harder and rougher bottom types such as rocky outcrops or coarse sediment typically return stronger intensities (high backscatter, lighter tones), whereas softer bottom types such as fine sediment return weaker intensities (low backscatter, darker tones). A map that show these data are published in Scientific Investigations Map 3319, "California State Waters Map Series--Offshore of Refugio Beach, California." This layer is part of USGS Data Series 781. In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP) to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats and geology within the 3-nautical-mile limit of California's State Waters. CSMP has divided coastal California into 110 map blocks, each to be published individually as United States Geological Survey Open-File Reports (OFRs) or Scientific Investigations Maps (SIMs) at a scale of 1:24,000. Maps display seafloor morphology and character, identify potential marine benthic habitats and illustrate both the seafloor geology and shallow (to about 100 m) subsurface geology. Data layers for bathymetry, bathymetric contours, acoustic backscatter, seafloor character, potential benthic habitat and offshore geology were created for each map block, as well as regional-scale data layers for sediment thickness, depth to transition, transgressive contours, isopachs, predicted distributions of benthic macro-invertebrates and visual observations of benthic habitat from video cruises over the entire state. This coverage can be used to to aid in assessments and mitigation of geologic hazards in the coastal region and to provide sufficient geologic information for land-use and land-management decisions both onshore and offshore. These data are intended for science researchers, students, policy makers, and the general public. This information is not intended for navigational purposes.The data can be used with geographic information systems (GIS) software to display geologic and oceanographic information. Dartnell, P., Phillips, E.L., Finlayson, D.P. (2015). Backscatter: Offshore of Refugio Beach, California, 2015. California State Waters Map Series Data Catalog: U.S. Geological Survey Data Series 781. Available at: http://purl.stanford.edu/pb804hy8483. Information for the related USGS Pacific Coastal and Marine Science Center data collection field activities, S-8-08-SC online at http://walrus.wr.usgs.gov/infobank/s/s808sc/html/s-8-08-sc.meta.html. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

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  14. Title: Backscatter A (8101): Drakes Bay and Vicinity, California, 2010

    Contributors:

    Summary: This layer is a georeferenced raster image containing acoustic-backscatter data for Drakes Bay and the surrounding vicinity in California. The map of the area was generated from data collected by California State University, Monterey Bay (CSUMB), and by Fugro Pelagos. Mapping was completed between 2007 and 2010, using a combination of 200-kHz and 400-kHz Reson 7125, and 244-kHz Reson 8101 multibeam echosounders, as well as 468-kHz SEA SWATHPlus interferometric system. These mapping missions combined to collect backscatter data (sheet 3) from about the 10-m isobath to beyond the 3-nautical-mile limit of Californiaís State Waters. Backscatter is a remote sensing activity by which electromagnetic energy is reflected back towards its source by terrain or particles. Within the acoustic-backscatter imagery, brighter tones indicate higher backscatter intensity, and darker tones indicate lower backscatter intensity. The intensity represents a complex interaction between the acoustic pulse and the seafloor, as well as characteristics within the shallow subsurface, providing a general indication of seafloor texture and composition. Backscatter intensity depends on the acoustic source level; the frequency used to image the seafloor; the grazing angle; the composition and character of the seafloor, including grain size, water content, bulk density, and seafloor roughness; and some biological cover. Harder and rougher bottom types such as rocky outcrops or coarse sediment typically return stronger intensities (high backscatter, lighter tones), whereas softer bottom types such as fine sediment return weaker intensities (low backscatter, darker tones). This layer is part of USGS Data Series 781. In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP) to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats and geology within the 3-nautical-mile limit of California's State Waters. CSMP has divided coastal California into 110 map blocks, each to be published individually as United States Geological Survey Open-File Reports (OFRs) or Scientific Investigations Maps (SIMs) at a scale of 1:24,000. Maps display seafloor morphology and character, identify potential marine benthic habitats and illustrate both the seafloor geology and shallow (to about 100 m) subsurface geology. Data layers for bathymetry, bathymetric contours, acoustic backscatter, seafloor character, potential benthic habitat and offshore geology were created for each map block, as well as regional-scale data layers for sediment thickness, depth to transition, transgressive contours, isopachs, predicted distributions of benthic macro-invertebrates and visual observations of benthic habitat from video cruises over the entire state. These data are intended for science researchers, students, policy makers, and the general public. This information is not intended for navigational purposes.The data can be used with geographic information systems (GIS) software to display geologic and oceanographic information. Dartnell, P. and Kvitek, R.G. (2014). Backscatter A (8101): Drakes Bay and Vicinity, California, 2010. California State Waters Map Series Data Catalog: U.S. Geological Survey Data Series 781. Available at: http://purl.stanford.edu/bh565zz1424. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

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  15. Title: Backscatter C (Swath): Offshore of Tomales Point, California, 2010

    Contributors:

    Summary: This layer is a georeferenced raster image containing acoustic-backscatter data for the offshore area of Tomales Point, California. The acoustic-backscatter map of the area was generated from data collected by California State University, Monterey Bay (CSUMB), Fugro Pelagos and by the U.S. Geological Survey (USGS). Mapping was completed between 2004 and 2010, using a combination of 200-kHz and 400-kHz Reson 7125, and 244-kHz Reson 8101 multibeam echosounders, as well as 234-kHz and 468-kHz SEA SWATHPlus phase-differencing sidescan sonars. These mapping missions combined to collect backscatter data from about the 10-m isobath to beyond the 3-nautical-mile limit of California's State Waters. Within the acoustic-backscatter imagery, brighter tones indicate higher backscatter intensity, and darker tones indicate lower backscatter intensity. The intensity represents a complex interaction between the acoustic pulse and the seafloor, as well as characteristics within the shallow subsurface, providing a general indication of seafloor texture and composition. Backscatter intensity depends on the acoustic source level; the frequency used to image the seafloor; the grazing angle; the composition and character of the seafloor, including grain size, water content, bulk density, and seafloor roughness; and some biological cover. Harder and rougher bottom types such as rocky outcrops or coarse sediment typically return stronger intensities (high backscatter, lighter tones), whereas softer bottom types such as fine sediment return weaker intensities (low backscatter, darker tones). A map that shows these data is published in Open-File Report 2015-1088, "California State Waters Map Series--Offshore of Tomales Point, California." This layer is part of USGS Data Series 781. In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP) to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats and geology within the 3-nautical-mile limit of California's State Waters. CSMP has divided coastal California into 110 map blocks, each to be published individually as United States Geological Survey Open-File Reports (OFRs) or Scientific Investigations Maps (SIMs) at a scale of 1:24,000. Maps display seafloor morphology and character, identify potential marine benthic habitats and illustrate both the seafloor geology and shallow (to about 100 m) subsurface geology. Data layers for bathymetry, bathymetric contours, acoustic backscatter, seafloor character, potential benthic habitat and offshore geology were created for each map block, as well as regional-scale data layers for sediment thickness, depth to transition, transgressive contours, isopachs, predicted distributions of benthic macro-invertebrates and visual observations of benthic habitat from video cruises over the entire state. This coverage can be used to to aid in assessments and mitigation of geologic hazards in the coastal region and to provide sufficient geologic information for land-use and land-management decisions both onshore and offshore. These data are intended for science researchers, students, policy makers, and the general public. This information is not intended for navigational purposes.The data can be used with geographic information systems (GIS) software to display geologic and oceanographic information. Dartnell, P., Erdey, M.D., Kvitek, R.G., and Bretz, C.K. (2014). Backscatter C (Swath): Offshore of Tomales Point, California, 2010. California State Waters Map Series Data Catalog: U.S. Geological Survey Data Series 781. Available at: http://purl.stanford.edu/sn970qh2871. None This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

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  16. Title: Faults: Offshore of Refugio Beach, California, 2012

    Contributors:

    Summary: This line shapefile contains fault lines within the offshore area of Refugio Beach, California. This map area lies within the Western Transverse Ranges province, north of the southern California Borderland (Fisher and others, 2009). This province has undergone significant north-south compression since the Miocene, and recent global positioning system (GPS) data suggest north-south shortening of about 6 mm/yr (Larson and Webb, 1992). The active west-trending Pitas Point Fault (broad zone including back faults), Red Mountain Fault, and Rincon Creek Fault are some of the structures on which this shortening occurs (e.g., Jackson and Yeats, 1982; Sorlien and others, 2000; Fisher and others, 2009). This fault system, in aggregate, extends for about 100 km through the Ventura and Santa Barbara basins and represents an important earthquake hazard (e.g., Fisher and others, 2009). A map that show these data are published in Scientific Investigations Map 3319, "California State Waters Map Series--Offshore of Refugio Beach, California." This layer is part of USGS Data Series 781. In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP) to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats and geology within the 3-nautical-mile limit of California's State Waters. CSMP has divided coastal California into 110 map blocks, each to be published individually as United States Geological Survey Open-File Reports (OFRs) or Scientific Investigations Maps (SIMs) at a scale of 1:24,000. Maps display seafloor morphology and character, identify potential marine benthic habitats and illustrate both the seafloor geology and shallow (to about 100 m) subsurface geology. Data layers for bathymetry, bathymetric contours, acoustic backscatter, seafloor character, potential benthic habitat and offshore geology were created for each map block, as well as regional-scale data layers for sediment thickness, depth to transition, transgressive contours, isopachs, predicted distributions of benthic macro-invertebrates and visual observations of benthic habitat from video cruises over the entire state. This coverage can be used to to aid in assessments and mitigation of geologic hazards in the coastal region and to provide sufficient geologic information for land-use and land-management decisions both onshore and offshore. These data are intended for science researchers, students, policy makers, and the general public. This information is not intended for navigational purposes.The data can be used with geographic information systems (GIS) software to display geologic and oceanographic information. Conrad, J.E., Ritchie, A.C., Johnson, S.Y. (2015). Faults: Offshore of Refugio Beach, California, 2012. California State Waters Map Series Data Catalog: U.S. Geological Survey Data Series 781. Available at: http://purl.stanford.edu/yg931nr6687. Map political location: Santa Barbara County, California Compilation scale: 1:24,000 Base maps used are hillshades generated from IfSAR, LiDAR, and multibeam mapping both onshore and offshore (see sheet 2, SIM 3319, for more information). References Cited: Fisher, M.A., Sorlien, C.C., and Sliter, R.W., 2009, Potential earthquake faults offshore southern California from the eastern Santa Barbara channel to Dana Point, in Lee, H.J., and Normark, W.R., eds., 2009, Earth science in the urban ocean: The Southern California Continental Borderland: Geological Society of America Special Paper 454, p. 271-290. Jackson, P.A., and Yeats, R.S., 1982, Sructural evolution of Carpinteria basin, western Tranverse Ranges, California: American Association of Petroleum Geologists Bulletin, v. 66, p. 805-829. Larson, K.M., and Webb, F.H., 1992, Deformation in the Santa Barbara Channel from GPS measurements 1987-1991: Geophysical News Letters, v. 19, p. 1491-1494. Sorlien, C.C., Gratier, J.P., Luyendyk, B.P., Hornafius, J.S., and Hopps, T.E., 2000, Map restoration of folded and faulted late Cenozoic strata across the Oak Ridge fault, onshore and offshore Ventura basin, California: Geological Society of America Bulletin, v. 112, p. 1080-1090. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

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  17. Title: Geology: Offshore of Refugio Beach, California, 2012

    Contributors:

    Summary: This polygon shapefile contains geological features for the offshore area of Refugio Beach, California. The offshore Refugio Beach map area largely consists of a gently offshore-dipping (<1 degree) shelf (10 to ~ 90 m) underlain by sediments derived primarily from relatively small coastal watersheds draining the Santa Ynez Mountains. Nearshore and shelf deposits are primarily sand (Qms) at depths less than about 45 m and more fine-grained sediment - very fine sand, silt and clay (Qmsf), at depths greater than about 45 m. The boundary between Qms and Qmsf is based on observations and extrapolation from sediment sampling (for example, Reid and others, 2006) and camera groundtruthing. The Qms-Qmsf boundary is transitional and approximate, expected to shift based on seasonal to annual to decadal scale cycles in wave climate, sediment supply, and sediment transport. Fine-grained deposits similar to Qmsf also occur below the shelfbreak on the upper slope at water depths greater than 90 m, where they are broken out as a separate unit (Qmsl) based on their location and geomorphology. More coarse-grained deposits recognized on the basis of high backscatter and in some cases moderate seafloor relief have two modes of occurrence. In the relative nearshore (10 to 30 m water depth), coarse-grained strata (Qmsc) underlie laterally coalescing and discontinuous bars at the mouths of steep coastal watersheds. Coarser-grained sediments also form several distinct lobes (Qmscl) in water depths of 25 to 70 m, about 600 to 3,000 m offshore. The lobes range in size from ~100,000 m2 to ~1.5 km2 and are mapped on the basis of high backscatter and subtle positive seafloor relief. These coarse-grained strata were clearly derived from fluvial point sources in the adjacent, steep Santa Ynez Mountains. Bedrock exposures in the nearshore west of El Capitan are assigned to the Miocene Monterey Formation based on proximity to coastal outcrops mapped by Dibblee (1981a, b). Much of the outer shelf (water depths greater than 70 m) is also underlain by undifferentiated Tertiary bedrock (Tbu). Based on the regional cross sections constrained by deep seismic-reflection data and borehole logs (Heck, 1998; Tennyson and Kropp, 1998; Forman and Redin, 2005; Redin, 2005) and high-resolution seismic-reflection data coupled with proprietary oil industry dartcore data (Ashley, 1977), these outer-shelf outcrops consist of the Miocene Sisquoc Formation and the Pliocene Repetto and Pico Formations. These rocks have been uplifted in a large, warped, regional south-dipping homocline that formed above the blind, north-dipping North Channel fault. The fault tip is inferred at about 1.5 sec TWT (~2 km) about 6 to 7 km offshore, beneath the slope and just outside California's State Waters. Bedrock that underlies some parts of the shelf is overlain by a thin (< 1 m?) sediment veneer, recognized based on high backscatter, flat relief, continuity with moderate to high relief bedrock outcrops, and (in some cases) high-resolution, seismic-reflection data (Qms/Qtbu. Qms/Tbu, Qms/Tm). These sediment layers are likely ephemeral - they may or may not be present based on storms, seasonal/annual patterns of sediment movement, or longer-term climate cycles. This area has a long history of petroleum production (Barnum, 1998), and grouped to solitary pockmarks (Qmp) caused by gas seeps are common features in the offshore Refugio map area. Shell discovered the Molino gas field in 1962, 4 km offshore in the southwest part of the map area. Production, by onshore directional drilling of an anticlinal trap, has been underway since the 1960's (Galloway, 1998). A map that show these data are published in Scientific Investigations Map 3319, "California State Waters Map Series--Offshore of Refugio Beach, California." This layer is part of USGS Data Series 781. In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP) to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats and geology within the 3-nautical-mile limit of California's State Waters. CSMP has divided coastal California into 110 map blocks, each to be published individually as United States Geological Survey Open-File Reports (OFRs) or Scientific Investigations Maps (SIMs) at a scale of 1:24,000. Maps display seafloor morphology and character, identify potential marine benthic habitats and illustrate both the seafloor geology and shallow (to about 100 m) subsurface geology. Data layers for bathymetry, bathymetric contours, acoustic backscatter, seafloor character, potential benthic habitat and offshore geology were created for each map block, as well as regional-scale data layers for sediment thickness, depth to transition, transgressive contours, isopachs, predicted distributions of benthic macro-invertebrates and visual observations of benthic habitat from video cruises over the entire state. This coverage can be used to to aid in assessments and mitigation of geologic hazards in the coastal region and to provide sufficient geologic information for land-use and land-management decisions both onshore and offshore. These data are intended for science researchers, students, policy makers, and the general public. This information is not intended for navigational purposes.The data can be used with geographic information systems (GIS) software to display geologic and oceanographic information. Conrad, J.E., Ritchie, A.C., Johnson, S.Y. (2015). Geology: Offshore of Refugio Beach, California, 2012. California State Waters Map Series Data Catalog: U.S. Geological Survey Data Series 781. Available at: http://purl.stanford.edu/pp901rg4093. Map political location: Santa Barbara County, California Compilation scale: 1:24,000 Base maps used are hillshades generated from IfSAR, LiDAR, and multibeam mapping both onshore and offshore (see sheet 2, SIM 3319 for more information). ). References cited: Ashley, R.J., Berry, R.W., and Fischer, P.J., 1977, Offshore geology and sediment distribution of the El Capitan-Gaviota continental shelf, northern Santa Barbara Channel, California: Journal of Sedimentary Petrology, v. 47, no, 1, p. 199-208. Barnum, H.P., 1998, Redevelopment of the western portion of the Rincon offshore oil field, Ventura, California, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, p. 201â215. Dibblee, T.W., Jr., 1981a, Geologic map of the Tajiquas Quadrangle, California: U.S. Geological Survey Open-File Report 81-371, 1:24,000. Dibblee, T.W., Jr., 1981b, Geologic map of the Gaviota Quadrangle, California: U.S. Geological Survey Open-File Report 81-374, 1:24,000. Dibblee, T.W., Jr., 1981c, Geologic map of the Santa Ynez Quadrangle, California: U.S. Geological Survey Open-File Report 81-371, 1:24,000. Dibblee, T.W., Jr., 1981d, Geologic map of the Solvang Quadrangle, California: U.S. Geological Survey Open-File Report 81-372, 1:24,000. Forman, J., and Redin, T., 2005, Santa Barbara Channel structure and correlation sections, Correlation Section no 37, Arroyo Hondo, Gaviota Quadrangle, Santa Ynez Mts. To North West Santa Rosa Island: American Association of Petroleum Geologists, Pacific Section, Publication CS 37, 1 sheet. Galloway, J.M., 1998, Chronology of petroleum exploration and development in the Santa Barbara channel area, offshore southern California, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section and Coast Geological Society, Miscellaneous Publication 46, p. 1â12, 1 sheet. Heck, R.G., 1998, Santa Barbara Channel Regional Formline Map, Top Monterey Formation, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., 1998, Structure and Petroleum Geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section, Miscellaneous Publication 46, Plate 1. Minor, S.A., Kellogg, K.S., Stanley, R.G., Gurrola, L.D., Keller, E.A., and Brandt, T.R., 2009, Geologic map of the Santa Barbara coastal plain area, Santa Barbara County, California: U.S. Geological Survey Scientific Investigations Map 3001, scale 1:25,000. Redin, T., 2005, Santa Barbara Channel structure and correlation sections, Correlation Section no 36, N-S structure and correlation section, western Santa Ynez Mountains across the Santa Barbara channel to Santa Rosa Island: American Association of Petroleum Geologists, Pacific Section, Publication CS 35, 1 sheet. Reid, J.A., Reid, J.M., Jenkins, C.J., Zimmerman, M., Williams, S.J., and Field, M.E., 2006,usSEABED:Pacific Coast (California Oregon, Washington) offshore surficial-sediment data release: U.S. Geological Survey Data Series 182, http://pubs.usgs.gov/ds/2006/182/. Tennyson, M.E., and Kropp, A.P., 1998, Regional cross section across Santa Barbara channel from northwestern Santa Rosa Island to Canada de Molina, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., in Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section and Coast Geological Society, Miscellaneous Publication 46, 1 plate. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

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  18. Title: Contours: Offshore of Refugio Beach, California, 2015

    Contributors:

    Summary: This line shapefile contains bathymetric contours at 10 and 50 meter intervals for the offshore area of Refugio Beach, California. A map that show these data are published in Scientific Investigations Map 3319, "California State Waters Map Series--Offshore of Refugio Beach, California." This layer is part of USGS Data Series 781. In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP) to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats and geology within the 3-nautical-mile limit of California's State Waters. CSMP has divided coastal California into 110 map blocks, each to be published individually as United States Geological Survey Open-File Reports (OFRs) or Scientific Investigations Maps (SIMs) at a scale of 1:24,000. Maps display seafloor morphology and character, identify potential marine benthic habitats and illustrate both the seafloor geology and shallow (to about 100 m) subsurface geology. Data layers for bathymetry, bathymetric contours, acoustic backscatter, seafloor character, potential benthic habitat and offshore geology were created for each map block, as well as regional-scale data layers for sediment thickness, depth to transition, transgressive contours, isopachs, predicted distributions of benthic macro-invertebrates and visual observations of benthic habitat from video cruises over the entire state. This coverage can be used to to aid in assessments and mitigation of geologic hazards in the coastal region and to provide sufficient geologic information for land-use and land-management decisions both onshore and offshore. These data are intended for science researchers, students, policy makers, and the general public. This information is not intended for navigational purposes.The data can be used with geographic information systems (GIS) software to display geologic and oceanographic information. Ritchie, A.C., Dartnell, P., Kvitek, R.G., Johnson, S.Y. (2015). Contours: Offshore of Refugio Beach, California, 2015. California State Waters Map Series Data Catalog: U.S. Geological Survey Data Series 781. Available at: http://purl.stanford.edu/cj457gj7638. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

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  19. Title: Backscatter B (7125): Offshore of Tomales Point, California, 2010

    Contributors:

    Summary: This layer is a georeferenced raster image containing acoustic-backscatter data for the offshore area of Tomales Point, California. The acoustic-backscatter map of the area was generated from data collected by California State University, Monterey Bay (CSUMB), Fugro Pelagos and by the U.S. Geological Survey (USGS). Mapping was completed between 2004 and 2010, using a combination of 200-kHz and 400-kHz Reson 7125, and 244-kHz Reson 8101 multibeam echosounders, as well as 234-kHz and 468-kHz SEA SWATHPlus phase-differencing sidescan sonars. These mapping missions combined to collect backscatter data from about the 10-m isobath to beyond the 3-nautical-mile limit of California's State Waters. Within the acoustic-backscatter imagery, brighter tones indicate higher backscatter intensity, and darker tones indicate lower backscatter intensity. The intensity represents a complex interaction between the acoustic pulse and the seafloor, as well as characteristics within the shallow subsurface, providing a general indication of seafloor texture and composition. Backscatter intensity depends on the acoustic source level; the frequency used to image the seafloor; the grazing angle; the composition and character of the seafloor, including grain size, water content, bulk density, and seafloor roughness; and some biological cover. Harder and rougher bottom types such as rocky outcrops or coarse sediment typically return stronger intensities (high backscatter, lighter tones), whereas softer bottom types such as fine sediment return weaker intensities (low backscatter, darker tones). A map that shows these data is published in Open-File Report 2015-1088, "California State Waters Map Series--Offshore of Tomales Point, California." This layer is part of USGS Data Series 781. In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP) to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats and geology within the 3-nautical-mile limit of California's State Waters. CSMP has divided coastal California into 110 map blocks, each to be published individually as United States Geological Survey Open-File Reports (OFRs) or Scientific Investigations Maps (SIMs) at a scale of 1:24,000. Maps display seafloor morphology and character, identify potential marine benthic habitats and illustrate both the seafloor geology and shallow (to about 100 m) subsurface geology. Data layers for bathymetry, bathymetric contours, acoustic backscatter, seafloor character, potential benthic habitat and offshore geology were created for each map block, as well as regional-scale data layers for sediment thickness, depth to transition, transgressive contours, isopachs, predicted distributions of benthic macro-invertebrates and visual observations of benthic habitat from video cruises over the entire state. This coverage can be used to to aid in assessments and mitigation of geologic hazards in the coastal region and to provide sufficient geologic information for land-use and land-management decisions both onshore and offshore. These data are intended for science researchers, students, policy makers, and the general public. This information is not intended for navigational purposes.The data can be used with geographic information systems (GIS) software to display geologic and oceanographic information. Dartnell, P., Erdey, M.D., Kvitek, R.G., and Bretz, C.K. (2014). Backscatter B (7125): Offshore of Tomales Point, California, 2010. California State Waters Map Series Data Catalog: U.S. Geological Survey Data Series 781. Available at: http://purl.stanford.edu/sb976wc2810. None This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

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  20. Title: Backscatter A (8101): Offshore of Tomales Point, California, 2010

    Contributors:

    Summary: This layer is a georeferenced raster image containing acoustic-backscatter data for the offshore area of Tomales Point, California. The acoustic-backscatter map of the area was generated from data collected by California State University, Monterey Bay (CSUMB), Fugro Pelagos and by the U.S. Geological Survey (USGS). Mapping was completed between 2004 and 2010, using a combination of 200-kHz and 400-kHz Reson 7125, and 244-kHz Reson 8101 multibeam echosounders, as well as 234-kHz and 468-kHz SEA SWATHPlus phase-differencing sidescan sonars. These mapping missions combined to collect backscatter data from about the 10-m isobath to beyond the 3-nautical-mile limit of California's State Waters. Within the acoustic-backscatter imagery, brighter tones indicate higher backscatter intensity, and darker tones indicate lower backscatter intensity. The intensity represents a complex interaction between the acoustic pulse and the seafloor, as well as characteristics within the shallow subsurface, providing a general indication of seafloor texture and composition. Backscatter intensity depends on the acoustic source level; the frequency used to image the seafloor; the grazing angle; the composition and character of the seafloor, including grain size, water content, bulk density, and seafloor roughness; and some biological cover. Harder and rougher bottom types such as rocky outcrops or coarse sediment typically return stronger intensities (high backscatter, lighter tones), whereas softer bottom types such as fine sediment return weaker intensities (low backscatter, darker tones). A map that shows these data is published in Open-File Report 2015-1088, "California State Waters Map Series--Offshore of Tomales Point, California." This layer is part of USGS Data Series 781. In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP) to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats and geology within the 3-nautical-mile limit of California's State Waters. CSMP has divided coastal California into 110 map blocks, each to be published individually as United States Geological Survey Open-File Reports (OFRs) or Scientific Investigations Maps (SIMs) at a scale of 1:24,000. Maps display seafloor morphology and character, identify potential marine benthic habitats and illustrate both the seafloor geology and shallow (to about 100 m) subsurface geology. Data layers for bathymetry, bathymetric contours, acoustic backscatter, seafloor character, potential benthic habitat and offshore geology were created for each map block, as well as regional-scale data layers for sediment thickness, depth to transition, transgressive contours, isopachs, predicted distributions of benthic macro-invertebrates and visual observations of benthic habitat from video cruises over the entire state. This coverage can be used to to aid in assessments and mitigation of geologic hazards in the coastal region and to provide sufficient geologic information for land-use and land-management decisions both onshore and offshore. These data are intended for science researchers, students, policy makers, and the general public. This information is not intended for navigational purposes.The data can be used with geographic information systems (GIS) software to display geologic and oceanographic information. Dartnell, P., Erdey, M.D., Kvitek, R.G., and Bretz, C.K. (2014). Backscatter A (8101): Offshore of Tomales Point, California, 2010. California State Waters Map Series Data Catalog: U.S. Geological Survey Data Series 781. Available at: http://purl.stanford.edu/tb879rs4686. None This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

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