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Great Lakes CoastWatch Java GIS


  1. Select Image Type

  2. Select Shapefiles of interest

  3. Press "Load Data" - files will appear in "Loaded ShapeFiles" window

  4. Press "Start"

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Java applet allows the examination of oceanographic satellite imagery with ancillary data sets (overlays). The applet will start two new windows (Panner window and Image window) for viewing the near real-time images and a Control Panel window for toggling on and off the marine observation data and shapefile overlays.

Image Data

Shape Files

Tips and FAQs


Frequently Asked Questions:

  1. How do I turn on marine observation data or other coverages (shapefiles)?
    In the Control Panel window, click on the "Menu" box to display available marine observation and nowcast wind data. Click on "coverages" to display a list of loaded shapefiles. Use the "Wind Vector" box to toggle marine observation data on or off. Use the box next to the shapefile of interest to toggle the overlay on or off.
  2. How do I change colors of the ancillary (overlay) data to make it more visible against the image background?
    Among the buttons in the Control Panel window is a choice box with a color name in it (black to start). Use this choice box to select a color. The colors for the shapefiles (coverages) are available from a separate dialog box when you turn the shapefile's checkbox on.
  3. How do I scroll or pan around the image?
    The Image Panner window contains a small version of the selected image. Inside this window is a black rectangle which starts near the upper left corner. The size and position of the rectangle reflect the view in the Image window. You can drag the rectangle to the area of the image you want to see in the Image window.
  4. How do I change the size of the Panner Image window's rectangle?
    The size of the rectangle changes automatically to reflect what is going on in the Image window. If you enlarge the Image window, the rectangle will get larger. If you zoom-in on the image in the Image window, the rectangle gets smaller.
  5. Is there a way to zoom-in and zoom-out using the mouse instead of the buttons (found under "View" in the Image window)?
    Yes. The buttons will zoom in or out while attempting to maintain the center of the image in the same place. If you use a three button mouse, the second and third buttons are used to zoom in and out and will maintain the point under the mouse at the same point on the screen. For a single button mouse, try using the shift and control keys.
  6. How can I save the image on the screen?
    The browsers security constraints prevent the applet from writing a file, such as a GIF, to your local machine. The only way for the applet to make an image file for you would be to create a GIF or JPEG, send it back to the server and have the server send it to your browser. Not only is this wasteful of bandwidth, it would open a nasty security problem on the server. The best way to save the image is to use a screen capture program such as WinGrab (freeware) or Snaglt (shareware) .