Hi Community,
I want to implement logic whereby my client-rendered layers don't display if there is no Bing basemap imagery for that particular extent/zoom level. As you know, with Bing as the basemap, you can zoom in very close, but at some point you get closer than Bing actually has imagery for.
The trouble I'm having is that the level at which Bing runs out of imagery is different, depending on where on the globe you are. In the U.S., for example, you can zoom into level 19 or so and still get imagery, whereas in Uzbekistan, you might only get 16 levels.
I thought I might test the returned jpeg name to see if it points to a generic NoImage.jpg image. Unfortunately, Bing doesn't do it this way. They always return a named tile image (a combination of the zoom level, row and column of the tile you are looking for), whether or not the tile has any real data, or if it's just the NoImage tile (they must have a lot of copies of the same "camera with a slash through it" image taking up space on their servers).
So now I'm stuck: how can do I know if Bing has imagery for a particlar extent at a particular zoom level or not? They don't seem to set a property, or raise an event.
Maybe there's a document somewhere detailing the max zoom level for different parts of the world?
Thanks in advance for your ideas.
Aaron
