Openstreetmap tile cache expiration?

[alimamo]

Being outside the USA, I am grateful that Openstreetmap tiles have finally made it into TopoFusion. I do have a question, though.

Seeing as Openstreetmap is always a "work-in-progress", the newest version of the tiles would of course be the best to have displayed in TopoFusion. Right now the tiles do cache, but is there a way to dump the OSM tile cache so one can have a newer set of tiles?

Not having the tile cache expire could actually be problematic. For instance, in one session you view the OSM tiles to a certain distance from a center point. On a subsequent session, you extend your viewing further out from the same center point. If the OSM data had been changed in the mean time, roads on the tiles pulled on the second session might not match those from tiles pulled and cached on the first session.

I was just wondering if you have thought about whether or not (and for how long) to cache OSM tiles?

Thanks for the great program.

Jama rek,

Robert

[ScottMorris]

Hi,

Thanks for bringing this up.  I have thought about it some, but couldn't decide on a good solution before releasing v4.  This also applies to the myTopo maps, which do get updates for fixes and such.

I'm not so sure there is an expiration life that makes sense to always apply.  So, I think perhaps the best way is to allow the user to either clear all tiles (of openstreetmap), or maybe just draw a box around an area and have those tiles be reset to be downloaded again.

Some people use TF in offline mode, so having an old map is better than no map, so I don't want to force expiration.

What do you think?

[alimamo]

Hi Scott,

The idea of just reloading tiles within a drawn box sounds like a good one, especially considering some areas rarely get updated very often.

However I still think it would be a good idea to be able to dump (clear all tiles) the entire cache. This would be useful in an area where there may be several people updating the OSM data. Also, after several bounded reloads, you might end up with quite a patch work of tiles, so the dump could be a good way to "level" the map again.

I agree that an expiration date might be problematic. If it could be set by the user, though, for some specific time period (or never) it might be OK.

Whatever you decide, I'm sure things will work out. Until the fix is implemented, though, is there currently a way to dump just a particular mapset?

Thanks again. Jama rek,

Robert

[alimamo]

Just wanted to say thanks for the function to expire all the OpenStreetMap maps.

I was getting quite a melange of tiles there. Now everything is hunky-dory again.

Thanks again and happy lunar new year.

Robert

[ScottMorris]

You are welcome, glad you saw the addition and thanks again for bringing it up.