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I am developing a mobile app for which an offline map is required. Is it possible to have such map within few 10s of MBs? The requirement is to have:

  1. Map with smaller zoom size; e.g. In this URL of Google Maps, the z denotes the zoom size (following longitude, latitude): https://www.google.co.in/maps/@12.9677753,77.6490654,15z; Hence 15 Google Map equivalent zoom size is manageable, I am ok with 14 as well if it reduces the size considerably
  2. The map can be a big image file with names of the street etc. printed
  3. The map should cover at least a country as big as US/Canada (if not the whole world)

Google maps doesn't seem to help. I also tried OpenStreetMap and its various links but what I found was the map size of 30-40 GB. I referred following question as well, but unable to get answer:
Offline Map Service with Mapnik and Leaflet

From where can I download such small size map or what is the minimal size of map which has bare minimal street view (not sure if this link can help)?

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There is no way you can get the map that small and still be readable like at that zoomlevel.

Just consider this:

  • the scalebar on gmaps (bottom right corner) is roughly 1", so even at z14: 1 km = 1 inch
  • an imaginary country with 1000km*1000km, so a map of that country would take 1000"x1000" (1000000)
  • you want it colored, so at least 8bit, i.e. *8
  • you want to identify objects within that 1km (=1"), so you can't use 1dpi .. let's take 50dpi, so *50

now we are at 1000000 * 8 * 50 =~ 50MB

what do we get for our 50MB?

  • 256 colors (might be enough for a street-map)
  • 50dpi, which isn't close to readable
  • a 1000*1000km country (as comparison: canada is ~5500km*4500km)
  • +1 thanks. Is it possible at least to download all the co-ordinates against the addresses in the world or a given country in simple text format. Using Google API, it takes too much of time. e.g., if we run Google API then 1 big city is covered in 3 hours, with .001 precision. (i.e. AB.XYZ, AB.XYZ format); This is too slow and I believe all these data should be stored somewhere ready made for quick download. – iammilind Mar 6 '15 at 10:41
  • Both, detailed Map-/Sat-Images and georeferenced Adresslists are a big Business. I don't think there is a way to get them (legally) for free. – ymirsson Mar 6 '15 at 11:17
  • Is it not possible through the free sites like OpenStreetMap or blueblackworks? I tried their FTP server, but couldn't find it in a downloadable way. – iammilind Mar 6 '15 at 12:02
  • You can download a full copy of the OSM Database here and extract all building nodes ... but OSM is nowhere near complete. As example: in Austria are roughly 2.7M registered buildings (i.e.: with street/houseno.). According to the latest Analysis OSM contains about 600k of them. So just 1/4 in a - more or less - high active area. – ymirsson Mar 6 '15 at 12:32

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