First off, I apologize if this is a novice question and/or if it has been asked already. I'm new to KML and so far, searching for 'GroundOverlay' and 'zoom' hasn't helped me.
I have created a KMZ file from an ESRI ArcGIS Layer. The KMZ includes a GroundOverlay (which is a PNG image). The KMZ opens and works fine in Google Earth, but now I would like to limit its visibility. My data is for the continental 48 US States and is meant to be viewed as such. So, zooming in to a 500-mile eye alt in Google Earth doesn't do the user any good. Is there a setting for GroundOverlay that turns its visibility off when the user is zoomed in to a specific level in Google Earth?
Thanks!
Making features visible in Google Earth when you're zoomed in/out can be controlled by adding a Region to your GroundOverlay. Same concept works for any KML Feature (i.e., Document, Folder, Placemark, GroundOverlay, NetworkLink, etc.)
You can simply add a Region to your GroundOverlay with maxLodPixels value to make it disappear when you're zoomed in. A more advanced setup could have smaller region-sized image overlays rather than a singe continent-sized overlay where each GroundOverlay has a Region for when when that overlay is visible. The visibility of the Region is defined when the bounds of the region (via LatLonAltBox) with respect to a minimum or maximum pixel size.
Note, however, that Google Earth won't let you create or edit a Region on a GroundOverlay directly so you'll need to add that to your KML outside of Google Earth. This and other limitations in Google Earth are listed here.
To get a feel for pixel sizes on the screen and create appropriate minimum pixel size (minLodPixels) and maximum size (maxLodPixels) you can measure the "screen" pixels dimensions with the KML screen ruler. Click "Raw" link to view raw KML then save locally and launch in Google Earth.