As a result of some suggestions from Steve, I've checked in some changes to the splitter (r87) that mean tiles are now trimmed of any extraneous empty space around their borders. Empty tiles are now thrown away completely. Also, no tiles extend past about +/-85 degrees latitude to prevent some erratic behaviour outside this range (so if you intend on heading to the north or south poles then this update is not for you!). Here's an example of the planet (date 090902) when split using the updated splitter: http://maps.google.co.uk/maps?q=http:%2F%2Fredyeti.net%2Fosm%2Fplanet-trim.k... As you can see the tiles are now quite a bit more compact, especially around densely mapped coastlines, and unmapped ocean areas are often not tiled at all. The only unusual thing I can see is tile 63240007 off the west coast of Mexico which contains just a single node. The node is part of this way: http://www.openstreetmap.org/browse/way/31775837 Looks like bad osm data that needs cleaning up/deleting? Chris