I'm creating a geolocalized app for Android and iPhone. This app shows a map with some interesting points that are on an sqlite database embeded on the app.
User can zoom out so then some too-many-markers technique is applyied, so a lot of points can be shown but grouped.
The interesting points are stored on a table which have a field for gps longitude and another field for gps latitude.
My question is: what is better for improve performance? To create 2 different index (one for gps_latitude, and one for gps_longitude) or to create 1 single icomposed index that includes two fields?
SELECT statements queries this table with a WHERE clause like this:
WHERE gps_longitude > ? AND gps_longitude < ?
AND gps_latitude > ? AND gps_latitude < ?