Problem zooming beyond level 15 using USGS Topo (and others)

[Mozzer]

When using combined zoom and zooming in from level 15 the map will switch to level 16 and sits there with the recycle icons on the screen. Sometimes it will say level 16 on the panel, but is clearly displaying level 15 (which is great - digital zoom). Sometimes the screen just shows the recycle icons. Whether the zoom works or not "appears" to be completely random.



Sometimes the digital zoom will occur (the map layer now says 16). If you let the screen turn off and then turn it back on, the screen just displays the recycle icons.



Sometimes I can be fine at level 17 (now digital zoom) and zoom back to 16 and the recycle icons reappear.



From my (the user's perspective) it appears that the software detects there is level 16 data available (which there might be) and clears the screen ready to receive it, but it never does receive it. Perhaps the API to the source is not functioning at their end (more on this below). I certainly can't tell. Perhaps a solution might be to not clear the screen, but perform a digital zoom until the tile has been correctly loaded.



If I use map creator to download some of the map, it tells me that level 16 data is available. The data quantity increases a lot when I choose this layer. However, if I zoom to an area (a few miles across) and repeat, it finds no data at level 16 and fails to download the tiles (but I have told it to ignore missing tiles so I get a map - see below).



If I now use this map, the digital zoom works OK (however, the map appears to shift position when I zoom - like the "Goto Map center" option is turned on - but it is not turned on). If I turn the "Goto map center" option on, the auto zoom now fails as it does with the online maps.



Unfortunately, where I am (West of Boulder, CO) the USGS Topo gives the "best" topo detail of any of the maps. Any ideas on this problem would be very much appreciated.



Thanks.

[Mozzer]

OK so I found a solution. Probably known to most of you already.



It seems, from using http://mobac.sourceforge.net/">MOBAC that the USGS Topo only has layers up to 15 zoom. So I edited the provided onlinemapsources.xml and changed the maxzoom value to 15 for USGS Topo.



That seemed to solve the problem.