what approach to use for this map requirement?

I would appreciate some points regarding the best approach to utilize for this requirements re OSM.

  • used in a mobile device, with ability for offline usage
  • what to show basic maps (e.g. like google’s standard road, terrain, satellite)
  • download map tiles for the given location/resolution, enough to let you cover the screen, then download more when required as the position changes
  • ability for user to selection a region (not too big) to download some maps for offline usage
  • ability within the mobile app to layer other graphics on top, so need a way to map the co-ordinates of a given position on a given tile to a lat/long I guess, and vice-a-versa

For example for the above do I just need to use the HTTP method like “http://a.tile.openstreetmap.org/7/63/42.png” to download the tiles. Reading the doco now but trying to find the reference API/doco so to speak that describes how to generate the URL you need for the map tile you want (i.e. a map tile for say, location X,Y, with resolution Z, and a terrain map say)

I am sure that many information you are looking for is cintained in the OSM wiki … see http://wiki.openstreetmap.org

Also see many available opensource software and frameworks dealing with OSM data …

How to address a specific tile via URL? see http://wiki.openstreetmap.org/wiki/Slippy_map_tilenames