The web mapping site 192.com has a very nice map zoom control which dynamically displays a representative image of the map at the prospective zoom level.
This nicely addresses a problem which has occurred in a few applications I've been involved with recently - how to communicate to the user what a given zoom level actually looks like.
At first I thought the control might be truly dynamic - i.e. pulling a live tile from the centre point of the current map view. But it's actually just a set of tile snippets at a fixed point. Still, it provides a very nice effect. (The dynamic version would be simple to implement, but perhaps would be too slow in actual use, with unpredicatable latency).
Are you listening, OpenLayers?
Cover design for the Refactoring 2nd Ed
1 week ago