Topography data from northern Monterey Bay, California, March 2015

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Frequently anticipated questions:

What does this data set describe?

Title:
Topography data from northern Monterey Bay, California, March 2015
Abstract:
This part of the data release presents topography data from northern Monterey Bay, California collected in March 2015. Topography data were collected on foot with survey-grade global navigation satellite system (GNSS) receivers mounted on backpacks and with an all-terrain vehicle (ATV) using a GNSS receiver mounted at a measured height above the ground.
Supplemental_Information:
Additional information about the field activities from which these data were derived are available online at:
http://cmgds.marine.usgs.gov/fan_info.php?fan=2015-625-FA
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  1. How might this data set be cited?
    Stevens, Andrew W., Logan, Joshua B., Hoover, Daniel J., and Snyder, Alexander G., 2017, Topography data from northern Monterey Bay, California, March 2015: data release DOI:10.5066/F76H4GCW, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    This is part of the following larger work.

    Stevens, Andrew W., Logan, Joshua B., Snyder, Alexander G., Hoover, Daniel J., Barnard, Patrick L., and Warrick, Jonathan A., 2017, Beach topography and nearshore bathymetry of northern Monterey Bay, California: data release DOI:10.5066/F76H4GCW, U.S. Geological Survey, Santa Cruz, CA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -122.030010
    East_Bounding_Coordinate: -121.788488
    North_Bounding_Coordinate: 36.978615
    South_Bounding_Coordinate: 36.807644
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 16-Mar-2015
    Ending_Date: 20-Mar-2015
    Currentness_Reference:
    ground condition at time data were collected
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: comma-delimited text
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Point (190797)
    2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is North American Datum of 1983, 2011 realization.
      The ellipsoid used is GRS_1980.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257222101.
      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: North American Vertical Datum of 1988
      Altitude_Resolution: 0.001
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    Attribute Table
    Table containing attribute information associated with the dataset (Source: Producer defined)
    Date and Time (yyyy-mm-dd HH:MM:SS.FFF)
    The date and time of data collection in Grenwich Mean Time (GMT). (Source: Producer Defined)
    Range of values
    Minimum:2015-03-16 18:37:13.000
    Maximum:2015-03-20 01:48:54.500
    Units:date and time in mm/dd/yyyy HH:MM:SS.FFF format
    Longitude (deg. E)
    Longitude coordinate of data point relative to the North American Datum of 1983 (2011 realization) (Source: Producer defined)
    Range of values
    Minimum:-122.030010
    Maximum:-121.788488
    Units:Decimal degrees
    Latitude (deg. N)
    Latitude coordinate of data point relative to the North American Datum of 1983 (2011 realization) (Source: Producer defined)
    Range of values
    Minimum:36.807644
    Maximum:36.978615
    Units:Decimal degrees
    Easting (m)
    East coordinate of data point relative to the North American Datum of 1983 (2011 realization), projected in the Universal Transverse Mercator (UTM), Zone 10 North, meters, coordinate system (Source: Producer defined)
    Range of values
    Minimum:586361.648
    Maximum:608033.168
    Units:meters
    Northing (m)
    North coordinate of data point relative to the North American Datum of 1983 (2011 realization), projected in the Universal Transverse Mercator (UTM), Zone 10 North, meters, coordinate system (Source: Producer defined)
    Range of values
    Minimum:4074216.909
    Maximum:4093028.038
    Units:meters
    Ellipsoid Height (m)
    Height in meters of data point with reference to the reference ellipsoid (Source: Producer defined)
    Range of values
    Minimum:-34.450
    Maximum:-18.600
    Units:meters
    Orthometric Height (m)
    Height in meters of data point with reference to the North American Vertical Datum of 1988. (Source: Producer defined)
    Range of values
    Minimum:-0.621
    Maximum:15.177
    Units:meters

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Andrew W. Stevens
    • Joshua B. Logan
    • Daniel J. Hoover
    • Alexander G. Snyder
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Andrew W. Stevens
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    Oceanographer
    2885 Mission St.
    Santa Cruz, CA
    USA

    831-460-7424 (voice)
    astevens@usgs.gov

Why was the data set created?

Data were obtained to document changes in shoreline position and coastal morphology as they relate to episodic (storms), seasonal, interannual, and longer (e.g. El Niño) processes. These data are intended for science researchers, students, policy makers, and the general public. These data can be used with geographic information systems or other software to identify topographic and shallow-water bathymetric features.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: 20-Mar-2015 (process 1 of 4)
    Topographic surveys of northern Monterey Bay, California were performed between March 16 and March 20, 2015. Topographic profiles were collected on foot with GNSS receivers mounted on backpacks. Prior to data collection, vertical distances between the GNSS antennas and the ground were measured using a tape measure. Hand-held data collectors were used to log raw data and display navigational information allowing surveyors to navigate survey lines spaced at 50- to 250-m intervals along the beach. Profiles were surveyed from the landward edge of the study area (either the base of a bluff, engineering structure, or just landward of the primary dune) over the beach foreshore, to wading depth on the same series of transects as nearshore bathymetric surveys that were conducted during the same time period. Additional topographic data were collected between survey lines with an all-terrain vehicle (ATV) to constrain the elevations and alongshore extent of major morphological features. Raw GNSS data were logged internally at 2-Hz intervals using a GNSS receiver mounted at a measured height above the ground.
    Date: 10-Sep-2015 (process 2 of 4)
    Positioning data from the survey platforms were post-processed to apply differential corrections from a GNSS base station with known horizontal and vertical coordinates relative to the North American Datum of 1983 (2011 realization). Post-processing of raw GNSS data was performed with Trimble Business Center and Waypoint Grafnav, for the backpack- and ATV- platforms, respectively. Orthometric elevations relative to the NAVD88 vertical datum were computed using National Geodetic Survey Geoid12a offsets. The final point data from the topographic surveyors are projected in cartesian coordinates using the Universal Transverse Mercator (UTM), Zone 10 North, meters coordinate system.
    Date: 13-Oct-2017 (process 3 of 4)
    All available topography data from the survey were compiled into a comma-delimited text file for distribution
    Date: 19-Oct-2020 (process 4 of 4)
    Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
  3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    Repeatability tests were conducted across different survey platforms, but no comparisons to "true" values were conducted.
  2. How accurate are the geographic locations?
    Survey-grade positions of the survey platforms were achieved with global navigation satellite system (GNSS) receivers and a single GNSS base station. The position of the GNSS base station was derived from two static GNSS occupations on January 14 and January 16, 2014, with durations of 6 and 3 hours, respectively. The static observations were processed using the National Geodetic Survey Online Positioning User Service (OPUS) and averaged to derive the final base station coordinates relative to the North American Datum of 1983 (2011 realization). Post-processing of raw GNSS data was performed with Trimble Business Center and Waypoint Grafnav, for the backpack- and ATV- platforms, respectively. Manufacturer reported accuracy for the differentially corrected horizontal positions for the GNSS rover trajectories is 0.8 cm + 0.5 ppm. Baselines from the GNSS base station varied between 1.5 km and 29 km with a mean of 13 km, suggesting an average horizontal accuracy of about 1.5 cm. Uncertainty in the horizontal positions associated with sinking into the substrate or variable posture during data collection of the surveyors is unknown.
  3. How accurate are the heights or depths?
    Manufacturer reported accuracy for the differentially corrected vertical positions for the GNSS rover trajectories is 1.5 cm + 1 ppm. Baselines from the GNSS base station varied between 1.5 km and 29 km with a mean of 13 km, suggesting the average vertical accuracy of topographic measurements to be about 3 cm. Uncertainty in the vertical positions associated with sinking into the substrate or variable posture during data collection of the surveyors is unknown.
  4. Where are the gaps in the data? What is missing?
    Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details.
  5. How consistent are the relationships among the observations, including topology?
    All data falls within expected ranges.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: none
Use_Constraints:
USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey as the originator(s) of the dataset and in products derived from these data. This information is not intended for navigational purposes.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - Science Base
    U.S. Geological Survey
    Denver Federal Center, Building 810, Mail Stop 302
    Denver, CO
    USA

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? Topography data are available as a comma-delimited text file (mb15_mar_topo.csv), along with associated FGDC-compliant metadata.
  3. What legal disclaimers am I supposed to read?
    Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 19-Oct-2020
Metadata author:
Andrew W. Stevens
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Oceanographer
2885 Mission St.
Santa Cruz, CA
USA

831-460-7424 (voice)
astevens@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/pcmsc/DataReleases/ScienceBase/DR_F76H4GCW/mb15_mar_topo_metadata.faq.html>
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