对于JSON，如下所示：

UsersLocation :{
     autoID1 : {....},
     autoID2 : {.....}
           }

试试这个：-

FIRDatabase.database().reference().child("UsersLocation").queryOrdered(byChild: "lat").queryStarting(atValue: 30).queryEnding(atValue: 60).observeSingleEvent(of: .value, with: {(snap) in

        print(snap)

        if let snapDict = snap.value as? [String:AnyObject]{

            for each in snapDict{

                print(each)

            }
        }
    })
}

这将给予你一个autoID键的所有用户，他们的纬度在30和60之间，你检索数据的顺序将是随机的，所以以升序遍历他们，你可以排序你收到的字典.

下面是一个你可以尝试的解决方案。这假设你已经把所有的帖子从Firebase下载到应用程序中，并存储在一个阵列中。你也可以考虑使用GeoFire，我个人没有使用过（但很想使用）。我相信它可以让你按位置查询Firebase，这样你就不必首先把所有的帖子下载到用户的设备上，然后在客户端进行过滤。

// assumes you have set up the app to get the user's current location
var currentLocation: CLLocation?

// Your array of posts downloaded from Firebase
var postArray = [post]()

let metersInTwentyFiveMiles = 40233.6

// You could put this in viewDidAppear after you load the post array from Firebase
for post in postArray {

    var distanceInMeters: CLLocationDistance = 0

    let postLocation = CLLocation(latitude: post.latitude, longitude: post.longitude)

    if let currentLocation = self.currentLocation {
         // Set distanceInMeters to the distance between the user's current location and the location of the post.
         distanceInMeters = currentLocation.distanceFromLocation(postLocation)
         // If this distance is not within 25 miles, remove this post from the array
         if self.metersInTwentyFiveMiles < distanceInMeters {
            self.posts = self.posts.filter{ $0 != post }
       }
    }
}

使用GeoHash
这里是它的完整文档，您可以使用单个https://firebase.google.com/docs/firestore/solutions/geoqueries
将此添加到您的播客文件pod 'GeoFire/Utils'
插入GeoHash

let latitude = 51.5074
let longitude = 0.12780
let location = CLLocationCoordinate2D(latitude: latitude, longitude: longitude)

let hash = GFUtils.geoHash(forLocation: location)

// Add the hash and the lat/lng to the document. We will use the hash
// for queries and the lat/lng for distance comparisons.
let documentData: [String: Any] = [
    "geohash": hash,
    "lat": latitude,
    "lng": longitude
]

let londonRef = db.collection("cities").document("LON")
londonRef.updateData(documentData) { error in
    // ...
}

获取筛选器数据

let queries = queryBounds.map { bound -> Query in
    return db.collection("cities")
        .order(by: "geohash")
        .start(at: [bound.startValue])
        .end(at: [bound.endValue])
}