Area Inundated by Mean Higher High Water, 2000

Frequently-anticipated questions:

What does this data set describe?

Title: Area Inundated by Mean Higher High Water, 2000
Abstract:
The polygon represents the extent of inundation due to Mean Higher High Water (MHHW) under current conditions (year 2000) based on NOAA tide stations tide elevation data.
Supplemental_Information:
The dataset covers the California coast with the exception of the San Francisco Bay which is covered in the layers created by Noah Knowles of USGS/SCRIPPS. The link for San Francisco Bay inundation is: <http://cascade.wr.usgs.gov>.
Due to data limitations, areas of Santa Barbara, Los Angeles and Orange counties were unable to be mapped. The breakdown of mappable area for those counties is: 49% of Santa Barbara County, 23% of Los Angeles County, and 65% of Orange County.
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, Mean Higher High Water, 2000: 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: -124.540400
    East_Bounding_Coordinate: -116.596022
    North_Bounding_Coordinate: 42.120914
    South_Bounding_Coordinate: 32.464390

  3. What does it look like?

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

    Calendar_Date: 2008
    Currentness_Reference:
    MHHW data represents the mean over a tidal epoch- epoch dates vary depening on the tide 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):

      • G-polygon (1480)

    2. What coordinate system is used to represent geographic features?

      The map projection used is Albers Conical Equal Area.

      Projection parameters:
      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 coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.000000
      Ordinates (y-coordinates) are specified to the nearest 0.000000
      Planar coordinates are specified in meters

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

      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?

    mhhw_2000

    Shape_Leng

    FID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Shape
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    Shape_Area
    Area of feature in internal units squared. (Source: ESRI)

    Positive real numbers that are automatically generated.

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?

The polygon layer was created for estimating the migration potential for wetlands as the area inundated due to MHHW changes along the California coast.

How was the data set created?

  1. From what previous works were the data drawn?

    (source 1 of 2)
    Institute, Pacific, mhhw_2000.

    Online Links:

    Type_of_Source_Media: ESRI shapefile

    (source 2 of 2)
    Institute, Pacific, Digital Elevation Models.

    Online Links:

    • Available upon request

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

    Date: 1901 (process 1 of 6)
    Using the Spatial Analyst extension, the 'Less than or equal to' tool was used in a python script to loop through all DEM datasets. The cells in the DEM that were less than or equal to the value in the mhhw_2000 raster were given a gridcode of '1' (true) all other land was coded '0'.

    Date: 1901 (process 2 of 6)
    Majority filter was run on the raster to clean edges and remove very small (1-2) pixel ponds from the raster.

    Date: 1901 (process 3 of 6)
    Convert raster to vector polygon (no simplification).

    Date: 1901 (process 4 of 6)
    Merge all polygons together into one layer.

    Date: 1901 (process 5 of 6)
    All small ponds less than 500 square meters were merged with surrounding area, therefore if small "island," convert to water, if small "pond," convert to land.

    Date: 1901 (process 6 of 6)
    Created buffer to select all ponds within 50 meters of main water body. Repeat this step, in cascading fashion, until no new polygons are selected. Effectively removes isolated "flooded" polygons from shapefile.

  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?

    Polygons indicate that land beneath the polygon has a lower elevation than the mhhw_2000 raster layer.
    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).

  2. How accurate are the geographic locations?

  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.
    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).

  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 11:55:10 2009