How tile-based, Google-style maps work

People often ask me how the maps in Gaia GPS work. Here’s the explanation I gave in email today:

All “Google-style” tile-based maps, which ours are, work as follows.

  • At zoom level 1, the whole world fits on 1 tile.
  • At zoom level 2, the whole world fits on 4 tiles.
  • At zoom level 3, the whole world fits on 16 tiles.
  • At zoom level N, the whole world fits on 4^N tiles.

For the MyTopo maps we use in Gaia GPS, you can fit a pretty big park area or city, with the finest level of detail, in about 10,000 tiles. Those tiles will take up hundreds of megabytes of space on your phone.

In Gaia GPS, you can download as many 100,000 tile chunks (increased from 10,000 on August 17) as you want. Gaia GPS Lite is still limited to 10,000 tiles per download.