California Tide Stations

Frequently-anticipated questions:


What does this data set describe?

Title: California Tide Stations
Abstract:
This is a small subset of 12 long-term tide stations on the California Coast. The elevations of Mean Lower Low Water (MLLW), Mean Low Water (MLW), Mean Sea Level (MSL), Mean High Water (MHW), and Mean Higher High Water (MHHW) are given fore each station. Each station has at least 30 years of records, sufficient for some trend analysis and for performing a frequency analysis on the tide elevations.
Supplemental_Information:
The station locations and tide data for all NOAA operated tide stations is available from NOAA in non-spatial format from the website: <http://tidesandcurrents.noaa.gov/station_retrieve.shtml?type=Tide+Data>
  1. How should this data set be cited?

    Heberger, Matthew, and Herrera, Pablo, 2009, California Tide Stations: The Impacts of Sea-Level Rise on the California Coast, Pacific Institute, Oakland CA.

    Online Links:

    This is part of the following larger work.

    Heberger, Matthew, Cooley, Heather, Gleick, Peter, and Herrera, Pablo, 2009, The Impacts of Sea-Level Rise on the California Coast: Pacific Institute, Oakland CA.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -124.216667
    East_Bounding_Coordinate: -117.173333
    North_Bounding_Coordinate: 41.745000
    South_Bounding_Coordinate: 32.713333

  3. What does it look like?

  4. Does the data set describe conditions during a particular time period?

    Calendar_Date: 2008
    Currentness_Reference: Time span of tidal measurements varies by station

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: vector digital data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Vector data set. It contains the following vector data types (SDTS terminology):

      • Entity point (12)

    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 0.000000. Longitudes are given to the nearest 0.000000. Latitude and longitude values are specified in Decimal degrees.

      The horizontal datum used is D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257224.

      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: North American Vertical Datum of 1988
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method: Attribute values

  7. How does the data set describe geographic features?

    CA_Tide_Stations

    FID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Shape
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    ID

    Station
    Station number

    Begin_Yr
    Year that tidal measuments began at the station

    End_Yr
    Year that tidal measuments ended at the station

    Duration
    Span, in years, that station has collected data

    Name
    Name of tide station

    Lat_Dec
    Latitude of station in decimal degrees

    Long_Dec
    Longitude of station in decimal degrees

    Web_Link
    Website where station data can be viewed

    State
    State in which station is located

    MLLW
    Mean Lower Low Water ( NAVD 88 meters)

    MLW
    Mean Low Water ( NAVD 88 meters)

    MSL
    Mean Sea Level ( NAVD 88 meters)

    MHW
    Mean High Water ( NAVD 88 meters)

    MHHW
    Mean Higher High Water ( NAVD 88 meters)


Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

  3. To whom should users address questions about the data?

    Pacific Institute
    c/o Matthew Heberger
    Research Associate/GIS Manager
    654 13th Street
    Oakland, CA 94612
    USA

    (510) 251-1600 (voice)
    (510) 251-2203 (FAX)
    mheberger@pacinst.org

    Hours_of_Service: 9:00 AM to 5:00 PM


Why was the data set created?

To derive elevations in a consistent datum (NAVD88) for tidal variation and elevations along the California Coastline.


How was the data set created?

  1. From what previous works were the data drawn?

    (source 1 of 1)
    NOAA, NOAA Tide Stations.

    Online Links:

    Type_of_Source_Media: ESRI shapefile

  2. How were the data generated, processed, and modified?

    Date: 2008 (process 1 of 1)
    Data from NOAA website was copied and placed in a Microsoft Excel spreadsheet, then imported to a shapefile in ArcGIS

  3. What similar or related data should the user be aware of?

    .

    This is part of the following larger work.

    ,.


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

  1. How well have the observations been checked?

    The data is derived directly from the NOAA tide information available online at: <http://tidesandcurrents.noaa.gov/station_retrieve.shtml?type=Tide+Data>. For attribute accuracy refer to the website.

  2. How accurate are the geographic locations?

    Locations of tide stations are provided in Decimal Degrees, which we projected into WGS 1984 using ArcGIS.

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?

    Data set has been visually inspected.

  5. How consistent are the relationships among the observations, including topology?

    The dataset is topologically correct.


How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints:
None. Data are freely downloadable and available for use in GIS and mapping subject the use constraints below.
Use_Constraints:
The data are freely redistributable with proper metadata and source attribution. Please reference the Pacific Institute as the originator of the dataset in any future products or research derived from these data. This information is being made available for informational purposes only. Users of this information agree by their use to hold blameless the State of California, and its respective officers, employees, agents, contractors, and subcontractors for any liability associated with its use in any form. This work shall not be used to assess actual coastal hazards, insurance requirements, or property values and specifically shall not be used in lieu of Flood Insurance Studies and Flood Insurance Rate Maps issued by the Federal Emergency Management Agency (FEMA).

  1. Who distributes the data set? (Distributor 1 of 1)

    Pacific Institute
    c/o Matthew Heberger
    Research Associate/GIS Manager
    654 13th Street,
    Preservation Park
    Oakland, CA 94612
    USA

    (510) 251-1600 (voice)
    (510) 251-2203 (FAX)
    mheberger@pacinst.org

    Hours_of_Service: 9:00 AM to 5:00 PM
  2. What's the catalog number I need to order this data set?

    Downloadable Data

  3. What legal disclaimers am I supposed to read?

    The data are freely redistributable with proper metadata and source attribution. Please reference the Pacific Institute as the originator of the dataset in any future products or research derived from these data.

  4. How can I download or order the data?

  5. What hardware or software do I need in order to use the data set?

    These data are available in Environmental Systems Research Institute (ESRI) shapefile format. The user must have ArcGIS or ArcView 3.0 or greater software to read and process the data file. In lieu of ArcView or ArcGIS, the user may utilize another GIS application package capable of importing the data. A free data viewer, ArcExplorer, capable of displaying the data is available from ESRI at www.esri.com.


Who wrote the metadata?

Dates:
Last modified: 24-Feb-2009
Metadata author:
Pacific Institute
c/o Matthew Heberger
Research Associate/GIS Manager
654 13th Street,
Preservation Park
Oakland, CA 94612
USA

(510) 251-1600 (voice)
(510) 251-2203 (FAX)
mheberger@pacinst.org

Hours_of_Service: 9:00 AM to 5:00 PM
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:


Generated by mp version 2.9.6 on Thu Feb 26 11:55:09 2009