License issue: Using OMS data in a commercial app

Hi all,

It appears there are already some iPhone apps which use OMS:

http://wiki.openstreetmap.org/wiki/Iphone

So if I make an app for a mobile device that uses an offline version of an OMS map (either a “copy” like a .png or a .pdf file or cached data), what kind of licensing issues arise (other than crediting OMS as the source of the map data)?

In this answer they say that you have to give credit to OMS which is understandable:

http://help.openstreetmap.org/questions/700/publishing-an-openstreetmap

Is there anything else that needs to be considered, e.g. if you offer an app with map data from a public source and the data gives bad directions to the user – who is liable?

(I think Apple has something in their EULA essentially stating “If you use our phone’s GPS and walk into an open manhole or fall into a cliff we are not liable”)

what kind of licensing issues arise

Crediting OSM is important, as you note. It doesn’t need to be on every screen (because of the tiny displays), but can be grouped with the Information or settings screen.

Regarding the display - if you use cached image tiles; generally you will not be able to scrape tiles from the OSM servers because of limits, your app will eventually be blocked. Possible tile sources are Cloudmade, Open Mapquest, or set up your own Mapnik server. Also consider displaying as vector data - newer phones are capable of vector displays with acceptable speed.

Is there anything else that needs to be considered, e.g. if you offer an app with map data from a public source and the data gives bad directions to the user – who is liable?

I am not a lawyer, so I have no idea who is liable. But clearly, it will be good to prominently display warnings and disclaimers.

Some like this one:
http://wiki.openstreetmap.org/wiki/OpenStreetMap:General_disclaimer