ubuntu-phone team mailing list archive

[Simos Xenitellis <simos.lists@xxxxxxxxxxxxxx>]

On Tue, Jun 2, 2015 at 10:18 PM, Frans Schreuder <fransschreuder@xxxxxxxxx>
wrote:

> Dear Ubuntu-phone mailing list,
>
> I have spent a few weeks developing an offline routing / navigation
> application (LGPL) based on openstreetmaps / libosmscout.
> I want to publish the app in the Ubuntu App Store, but I am facing a
> problem: I need read access on a location on the SD card. I will explain
> why.
>
> 1.) The maps take quite some space on the device (Netherlands is 1.3GB,
> Germany is 4+ GB). At least on the BQ Aquaris this space is not
> available in the home directory, at least not if you also want to remain
> with some space available.
>
> 2.) The maps have to be converted to a binary format with a tool on the
> PC. Until I got some server space and time to host some readily
> converted maps, the user will have to transfer maps manually to the
> phone. If this would be the app data space, that location is not by
> default readable if you browse the phone on the PC.
>
> 3.) Converting the maps on the phone is not really an option, as the
> process uses several GB as temp space, and on an i7 pc it can take over
> 1 hour for a map of a small country.
>
>
Could you use the OBF format, and possibly reuse (for now) the
pre-generated files
from http://download.osmand.net/rawindexes/ ?

The uncompressed OBF files are a bit less than 2x the corresponding ZIP
file.
For detailed countries (so huge OBF), the OSMAND project has split those
countries in regions.

In addition, I remember a very recent discussion about privacy concerns if
the maps are shared among applications.
That is, a third-party app could check what tiles are cached, thus figure
out where the user has been.
I could not find the exact discussion and Google search in my e-mails did
not help.
I would say that this is not a huge concern for the vector maps, because
they cover a whole country.
Thus, the privacy would be for an app that was forbidden to find the
location (no access to GPS, neither the MCC/MNC SIM details).
But still, the app can easily deduce the country anyway simply from GEOIP.

I think that having a way to support shared OBF files, so apps can reuse
them, would be a big win.
If an app needs OpenStreetMap maps for a non-cached region, then the
service that deals with the OBF files
would ask the user "Hey, you are trying to view the maps for Poland, shall
we download these?".

Simos