On Tue, Jun 2, 2015 at 10:18 PM, Frans Schreuder <[email protected]> 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
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