Correct datatype for latitude and longitude? (in activerecord)

Solution 1:

This is what I use:

add_column :table_name, :lat, :decimal, {:precision=>10, :scale=>6}
add_column :table_name, :lng, :decimal, {:precision=>10, :scale=>6}

Solution 2:

If you need to do more complex geographical calculations, you can investigate PostGIS for Postgresql or MySQL Spatial Extensions for MySQL. Otherwise, a float (double precision might be a good idea) should work.

Edit: It looks like the GeoRuby library includes a Rails extension for working with the spatial/GIS extensions for both of the aforementioned databases.

Solution 3:

If you're not using a spatially-enabled database, Google Maps recommends using floats of size (10,6). That gives you 6 digits after the decimal - if you want more precision, you can adjust accordingly.

Solution 4:

I would suggest using floats, although it doesn't really make that much of a difference. Floats are easier to do calculations on if you ever desire that in the future.

Solution 5:

Generally you want Lat/Long stored in the largest float type you have. At some latitudes (eg: near the equator) very small changes in longitude can equate to large differences in terms of surface distance.

I suppose if it is a field which you won't ever want to do any math on, you could use a string. I'd avoid that though.