Query between distances in Parse

Question

I would like to search places between two given distances, using GeoPoints. Using the currently api, I think I could make something like this pseudo algorithm:

query.whereWithinKilometers("directions", GlobalData.ownerGeoPoint, MAXIMUM distance);

MINUS

query.whereWithinKilometers("directions", GlobalData.ownerGeoPoint, MINIMUM distance);

How can I translate to real code?

Answer 1

Finally I found a way to do it with a parse query.

// Do not want locations further than maxDistance
ParseQuery query = ParseQuery.getQuery("MyData");
query.whereWithinKilometers("location", userGeoPoint, maxDistance);

// Do not want locations closer than minDistance
ParseQuery<ParseObject> innerQuery = ParseQuery.getQuery("MyData");
innerQuery.whereWithinKilometers("location", userGeoPoint, minDistance);
query.whereDoesNotMatchKeyInQuery("objectId", "objectId", innerQuery);

Answer 2

Likely you'll have to pull in everything within the maximum distance from Parse to your app, then inside your app filter out anything that is closer than the minimum.

Thankfully Parse includes some distance measuring as part of PFGeoPoint. Check out the three methods here.

1. distanceInRadiansTo:
2. distanceInMilesTo:
3. distanceInKilometersTo:

So your pseudocode is:

(After you get back everything within the outer radius)

Make a new array (var) called finalList
For i = 0; i < objects.count; i++ {
   var gp: PFGeoPoint = objects[i]
   if gp.distanceInMilesTo:originalGeoPoint >= minimumRadiusInMiles {
      finalList.push(gp)
   }
}