5.3 Toggle Buttons

When a user has a number of different data files to view and compare, the image area can become an indecipherable clutter if they are all visible simultaneously. For this reason, each viewable entity (swaths, overlays, and the map) has a toggle button accessible to the right of the image area. Each one is labelled with the file name of the item it affects (and the map button is labeled Map). When the item is graphically displayed, the toggle button label turns red. Otherwise the label is the normal color. Note that only one swath's toggle button can be on at a time. This doesn't preclude us from simultaneously looking at several satellite images in the same image area, but that discussion is reserved for the Properties section (Section 7).

Note that the toggle buttons for satellite swaths are menu buttons. Menu buttons are distinguished by having an inverted triangle (down arrow) after the button label. The arrow means that a pop-up menu will appear if the right mouse button is depressed when the cursor is over the button. In this case, the menu has several entries, each of which performs some operation on the swath.

Toggle Visibility:Toggles the visibility of the swath canvas.

Histogram:Computes a histogram of the image file.

Recompute Swath:Redraws the swath using current settings.

Destroy Swath:Removes the swath, and frees its resources.

The Recompute Swath function is useful if, for instance, you plot a satellite image, alter the current resolution, and want to view the satellite swath with the new resolution.

Each swath `remembers' its map projection and colormap. Thus, when you toggle a swath on, the current map projection reverts to the one under which the image was rendered, and the colormap will also change back (if it has been altered). If you wish to view a swath under a new projection, you may select Recompute Swath from its menu after setting the desired map projection. The colormap may be changed via the Miscellaneous panel in the Properties window (see Section 7.5).