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San Francisco Bay Bathymetry

Use zTool to examine a bathymetry data set. You can display a cross-section profile, and compute volume above and below the section. Using the polygon tool you can compute the volume of an outlined polygon at various tide levels.

PLEASE NOTE: zTool has been tested using Netscape rev 4.7 for UNIX and Windows, and Netscape 6.2 for MacOS and Windows. Your browser must have JavaScript enabled.

Data Sets:

To compute a cross-section area and plot the profile:

  • Select a data set from the list above
  • Select the tide level in the Bathy data box
  • If necessary use the scroll bars at the bottom and right of the image to locate your area of interest
  • Select the line tool
  • Locate the start of your profile with a single mouse click
  • Move to mouse to the end of your profile and terminate the profile with a second mouse click (use the RESET button to relocate your profile)
  • Click on the SUBMIT button to obtain your results

Example Input Screen:

zTool input screen example

Example Output Screen:

zTool output screen example

To compute volume of a polygon:

  • Select a data set from the list above
  • Select the tide level in the Bathy data box
  • If necessary, use the scroll bars at the bottom and right of the image to locate your area of interest
  • Select polygon tool and outline your polygon using the mouse; click at each vertex of the polygon; use the spacebar to end the outline selection
  • Use the Establish Seed button to set a start point for the volume calculation; after selecting Establish Seed, click anywhere within your polygon
  • Click on the SUBMIT button to obtain your results

Example Output Screen from Polygon Tool:

Using the POLYGON TOOL you can compute the volume of a portion of the Bay. In the example below, Suisun Bay has been outlined in the "Selection Window"; in the "Results Window", an image of the selected area and the volume of that segment is returned.

Polygon tool output screen example

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URL:http://sfbay.wr.usgs.gov/sediment/sfbay/zTool.html
Page Last Modified: Thursday, 13-May-2010 14:38:44 PDT