Example 2a: Keeping legends on the screen when the image is
zoomed and roamed
By adding the parameters:
image_preserve= 0,0,45,45, 3,340,48,740, 227,4, 800,23
those regions of the (base) images will be preserved when the
image(s) are zoomed and roamed. To keep portions of
overlay images on display, use the
overlay_preserve parameter (along with the
The "hide_" parameters prevent roaming into the legends on the
top and left.
In this example, click the zoom control, click a few times
in the images to zoom, and then "drag" to roam around. Note that
the 3 legends (date-time at the top, logo in the uuper left, and
colorbar on the left) stay in view.