San Francisco High Tide Elevations

Frequently-anticipated questions:

• What does this data set describe?
  1. How should this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  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?
  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?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

1. How should this data set be cited?

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

   Online Links:

   • <http://www.pacinst.org/reports/sea_level_rise>

   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:

   • <http://www.pacinst.org/reports/sea_level_rise>

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -122.506290

   East_Bounding_Coordinate: -121.943464

   North_Bounding_Coordinate: 38.154828

   South_Bounding_Coordinate: 37.429534

3. What does it look like?

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

   Calendar_Date: 1984

   Currentness_Reference: Study has not been updated

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 (52)

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

      Grid_Coordinate_System_Name: Universal Transverse Mercator

      Universal_Transverse_Mercator:

      UTM_Zone_Number: 10

      Transverse_Mercator:

      Scale_Factor_at_Central_Meridian: 0.999600

      Longitude_of_Central_Meridian: -123.000000

      Latitude_of_Projection_Origin: 0.000000

      False_Easting: 500000.000000

      False_Northing: 0.000000

      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?

   sf_high_tide_elev

   FID

   Internal feature number. (Source: ESRI)

   Sequential unique whole numbers that are automatically generated.

   Shape

   Feature geometry. (Source: ESRI)

   Coordinates defining the features.

   INDEX_NO

   index filed created for each tide station where data was collected

   FT_NGVD29

   Original values supplied by USACE study in vertical datum of NGVD29, feet.

   M_NAVD88

   Elevation value after converting feet to meters and NGVD29 to NAVD88 using the Vertcon tool.

Who produced the data set?

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

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?

Depict the estimated 100-year highest tide elevations for the San Francisco Bay.

How was the data set created?

1. From what previous works were the data drawn?

   (source 1 of 1)

   United States Army Corps of Engineers, 1984, San Francisco Bay Tidal Stage vs. Frequency Study.:, San Francisco, Ca.

   Type_of_Source_Media: ESRI shapefile

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

   Date: 1906 (process 1 of 4)

   Locations of tide stations and associated data were digitized from paper maps to shapefiles using heads-up-digitizing. Original data was provided on USGS 1:24,000 paper topo maps and created in a shapefile over DRG topo maps at the same extent

   Date: 1906 (process 2 of 4)

   Point ID and NGVD 29 elevations were input into an excel spreadsheet. Elevation values were converted to meters.

   (process 3 of 4)

   The shapefile and Excel spreadsheet were joined based on point ID and exported to a new shapefile.

   Date: 1906 (process 4 of 4)

   Elevation values were then converted from NGVD 29 to NAVD 88 using the Vertcon program.

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?

   Elevations for 100-yr flood are based on results from 1984 USACE report. See report for accuracy of elevations. Data was converted from NGVD29 feet to NGVD29 meters, then to NAVD88 meters using the Vertcon tool.

2. How accurate are the geographic locations?

   Locations of points are approximate. Locations were digitized based on paper versions of USGS 1:24,000 7.5 minute topo maps and located on DRG versions of the USGS topo maps at the same resolution.

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?
   • Availability in digital form:

     Data format:	ESRI data format, dependent upon request Files are zipped using the 7zip software. Size: 0.001

   • Cost to order the data: None

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: 26-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:

• <http://www.esri.com/metadata/esriprof80.html>