[Marble-devel] Marble with offline OSM maps

[Torsten Rahn]

Hi Jeremie,

On Dienstag, 15. Mai 2012 14:29:15 Jeremie Scheer wrote:
> > You might want to default to Mercator projection in Marble since that
> > delivers the best speed.
> How can you do that ? Is there a method in the code to default to Mercator
> ?

See part 2 of the Tutorial I referenced in my previous mail:

http://techbase.kde.org/Projects/Marble/MarbleMarbleWidget

As you can see there is a line 

 mapWidget->setProjection( Mercator ); 

which does this exactly. 

> > It's trivially easy to preload the tiled bitmaps
> 
> Where can you find tiled bitmaps from OSM on the Internet ? Or OSM files
> must be transformed to tiled bitmaps with Mapnik first ?

See the user documentation:

http://docs.kde.org/stable/en/kdeedu/marble/download-region.html

You can use the normal Marble client to download bitmap tile data right from 
the OpenStreetMap servers. 

Note that there are OSM server restrictions to the download of a single query 
(Marble's UI will inform you about those).

Make sure that the hard disc cache is big enough so that Marble will not 
automatically start to delete the data you are downloading. By default it 
measures around 300 MB which you might want to increase depending on the 
amount of data you want to keep:

http://docs.kde.org/stable/en/kdeedu/marble/configcacheproxy.html

The data for OSM will end up inside 

~/.local/share/marble/maps/earth/openstreetmap

You can either copy it into the very same place on your target device - or - 
you put it into the system wide place which might be e.g.:

/usr/local/share/marble/data/maps/earth/openstreetmap

(start Marble with "marble --debug-info" on the command line and look for the 
first few lines of output which looks like this:
System Path: "/usr/local/share/apps/marble/data" 
This will tell you the correct place for your system data where 
"maps/earth/openstreetmap" needs to get created inside )

If you keep it in the home directory on the target device then you also need 
to apply the cache limit settings on the MarbleWidget used on the device - 
otherwise Marble will delete excessive data automatically. So putting it into 
the System Path might be the better solution.

Of course the alternative would still be to create bitmap tiles via Mapnik on 
demand on your own server. That would require some additional magic on your 
own server however.

> Now if I have tiled bitmaps, how can I use them in Marble library being
> offline ?

You can use it right away if it's placed in the correct location on your hard 
disc. See above. :-)

Best Regards,

Torsten



> Regards,
> 
> > Am 15.05.2012 12:29, schrieb Torsten Rahn:
> >> As you can see there are still a few things missing (road labels,
> >> etc.) but we gladly accept patches ;) Note that Marble currently only
> >> support import of single files. So there is no "tile management" as
> >> it exists for the OSM bitmap map theme.
> >> 
> >>> Is it possible to do that with Marble ? And if so, could you explain me
> >>> the way it can be done (directly by code and not in Marble menus) ?
> > 
> > It's also useful to know that there's a GSOC project this year by
> > Ander that will further improve our OSM vector rendering towards
> > making it end-user ready.
> > 
> > Regards,
> > Dennis
> > 
> > _______________________________________________
> > Marble-devel mailing list
> > Marble-devel at kde.org
> > https://mail.kde.org/mailman/listinfo/marble-devel
> 
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