[Xastir] Announcing tile support for OSM

[Lee Bengston]

On Tue, Jul 27, 2010 at 12:10 PM, Jerry Dunmire <jerry at dunmire.org> wrote:
> Early this morning Curt committed my patches to add tile support for
> OSM to the CVS tree (thanks Curt).

Thanks Jerry!  Personally I am on a very fast internet connection at
home, so the static version performs just fine.  Still I am looking
forward to trying out the tiles.

> Tiles are small (256x256) map sections that get assembled on-the-fly
> to make an image that fills the xastir window. Since typical xastir
> windows are larger than 256x256, there is a small penalty for the
> extra http requests, but a big gain in re-use. Use of tiles is the key
> to 'slippy map' implementations in browsers and some newer apps (take
> a look at TangoGPS for an example). Tiles also improve the OSM
> experience with xastir, just don't expect 'slippy map' performance.
> Xastir's strengths like in other areas.
>
> There is an new README file describing OSM that gives a lot more
> details on both the static and tiled maps. Please read it carefully.

Nice!

> The default setup provides new OSM*.geo map description files. There
> are a mix of tiled and static maps. You can tell the difference by
> file name. While any of the OSM based styles could be tiled, the tiles
> from CloudMade require an access key. You have to register for at the
> CloudMade site to get a key and then modify the appropriate GEO file.
>
> The biggest weakness in the present tiling implementation is that a
> slow server, or worse one that does not respond, is a real problem
> since for large screens you could have to wait 20 or more tiles to
> time out before the display will refresh. The ski trail version of OSM
> was giving me headaches with timeouts yesterday- take care.
>
> I am working on a way to cancel the tile downloads, but since most
> sites are responsive I don't think you will run into too many problems
> (unless you are a skier - hi hi ).

I think I'll hold off on any new binaries or live CD remasters for now
given there could be some additional tweaks in the near future.

> Tiles are separated from the standard Xastir cache so that they can be
> shared with other OSM applications. I have successfully shared tiles
> between Xastir and TangoGPS. See the README.OSM_maps file for more
> details.

I'm very impressed.  Thanks again.

Lee - K5DAT
Murphy, TX