[mkgmap-dev] Satnav for non-proprietary maps?

Sun Feb 14 20:43:13 GMT 2016

On Sun, Feb 14, 2016 at 02:47:40PM -0500, Mark Bradley wrote:
>The other day I got to thinking-is there no such thing as a GPS/satnav 
>that can display maps created in an open-source format, such as .pbf?

First of all, navigation requires several features:

* Map display
* Routing graph information
* Address index

The first part is in my experience best done by maintaining a cache of 
map tiles in bitmap format on a MicroSD card. If you are moving in a 
"new" area for which your device is displaying map tiles for the first 
time, then it will take some time to fetch the vector data and render it 
into a bitmap. Typically, the device would quickly fetch and display 
already rendered tiles from the cache. The Mapsforge library works in 
this way.

To my knowledge, Mapsforge supports neither routing nor address search.  
For those you would need a different type of index.

I am not aware of any really good open source offline navigation 
application for Android. There is OsmAnd, but it consumes a lot of 
memory, because it does not maintain a cache of map tiles. It is not 
good at calculating routes, especially for bicycling. It can be 
interfaced with an external offline router http://brouter.de/ which uses 
its own file format.

Brouter can also be interfaced with the closed-source applications Locus 
Map and OruxMaps. Both of them are using MapsForge for displaying the 
maps. As far as I understand, OruxMaps does not support offline address 
search. I have not tried Locus Map, but OruxMaps seems useable on a 
low-end device, hardly ever crashing due to running out of memory. It 
stores tracks and sensor data in SQLite tables on the MicroSD card.

>Perhaps an analogy would be an unlocked cellphone-you pay extra for it 
>(or hack it), in exchange for additional flexibility.  I wonder if 
>there would be a market for such a thing.

http://linuxg.net/osmscout-is-an-offline-navigation-app-for-ubuntu-touch/

For me, Ubuntu Phone is interesting, but not enough to warrant a 
purchase. I hope that there will some day be devices that are based on a 
system-on-chip that is supported by the mainline Linux kernel. With both 
Android and Ubuntu, my understanding is that upgrading the kernel is 
practically impossible, because some drivers are tied to a specific 
kernel version.

	Marko