GeoFirestore返回太多结果

Question

我正在使用GeoFirestore对我的Firebase Firestore运行地理查询。它似乎通常可以正常工作，但是返回的结果比半径大于25英里的测试所返回的结果要多。我的Firestore中最近的位置距离我要测试的位置103英里。我已经以25英里的增量进行了测试。 25英里不返回任何位置，50英里返回最接近的位置，75英里返回最接近的位置，100英里返回我所有的测试位置。知道我在做什么错吗？

func getFacilites() {
        self.facilities = [[String: Any]]()

        let currentLatitude = self.currentLocation.coordinate.latitude
        let currentLongitude = self.currentLocation.coordinate.longitude

        let geoFireStore = Constants.geoFirestore
        let circleQuery = geoFireStore.query(withCenter: GeoPoint(latitude: currentLatitude, longitude: currentLongitude), radius: milesToKilometers())
        let _ = circleQuery.observeReady {
            print("All initial data has been loaded and events have been fired!")
        }
        let _ = circleQuery.observe(.documentEntered, with: { (key, location) in
            Constants.firestore.collection("facilities").document(key!).getDocument { (document, error) in
                if let document = document, document.exists {
                    self.facilities?.append(document.data()!)
                    self.addFaciltiesToMap()
                } else {
                    print("Document does not exist.")
                }
            }
        })
    }

func milesToKilometers() -> Double {
     // self.searchDistance is a Double value
     return self.searchDistance * 1.60934
}