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:

• Full Bay 100m grid - (1950-95 data)
• San Pablo Bay 50m grid - (1983 data)
• Suisun Bay 25m grid - (1990 data)

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:

Example Output Screen:

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.