iOS Servicios de ubicación Método para filtrar ubicaciones no válidas o incorrectas

Question

Estoy usando Location Services en algunas de mis aplicaciones. Tengo un método que utilizo en mi método locationManager:didUpdateToLocation:fromLocation: para filtrar ubicaciones malas, inexactas o muy lejanas. Y para minimizar gps "jitter". Esto es lo que uso:

/** 
* Check if we have a valid location 
* 
* @version $Revision: 0.1 
*/ 
+ (BOOL)isValidLocation:(CLLocation *)newLocation withOldLocation:(CLLocation *)oldLocation { 

    // Filter out nil locations 
    if (!newLocation) return NO; 

    // Filter out points by invalid accuracy 
    if (newLocation.horizontalAccuracy < 0) return NO; 
    if (newLocation.horizontalAccuracy > 66) return NO; 

    // Filter out points by invalid accuracy 
    #if !TARGET_IPHONE_SIMULATOR 
    if (newLocation.verticalAccuracy < 0) return NO; 
    #endif 

    // Filter out points that are out of order 
    NSTimeInterval secondsSinceLastPoint = [newLocation.timestamp timeIntervalSinceDate:oldLocation.timestamp]; 
    if (secondsSinceLastPoint < 0) return NO; 

    // Make sure the update is new not cached 
    NSTimeInterval locationAge = -[newLocation.timestamp timeIntervalSinceNow]; 
    if (locationAge > 5.0) return NO; 

    // Check to see if old and new are the same 
    if ((oldLocation.coordinate.latitude == newLocation.coordinate.latitude) && (oldLocation.coordinate.longitude == newLocation.coordinate.longitude)) 
     return NO; 

    return YES; 

}//end 

¿Alguien tiene alguna mejora en este método para hacerlo más preciso? ¿Es demasiado alto de horizontalAccuracy y recibirá muchas ubicaciones no válidas? ¿Debo bajar esto?

¿Hay alguna manera de obtener el "jitter" que da el gps en el iPhone?

Answer 1

Además de éstos hay uno más que utilizo:

if(self.lastKnownLocation) 
{ 
    CLLocationDistance dist = [newLocation distanceFromLocation:self.lastKnownLocation]; 

    if(dist > newLocation.horizontalAccuracy) 
    { 
      //..... 
    } 
} 

Dónde self.lastKnownLocation es en realidad la última posición válida tengo y es un:

@property(nonatomic, copy) CLLocation *lastKnownLocation; 

Answer 2

-(void)locationManager:(CLLocationManager *)manager 
    didUpdateToLocation:(CLLocation *)newLocation 
      fromLocation:(CLLocation *)oldLocation 
{ 
if (!newLocation) 
    { 
     NSLog(@"Filter out points by invalid accuracy"); 
     return; 
    } 

    // Filter out points by invalid accuracy 
    if (newLocation.horizontalAccuracy < 0) 
    { 
     return; 
    } 
    if(oldLocation.coordinate.latitude>90 && oldLocation.coordinate.latitude<-90 && oldLocation.coordinate.longitude>180 && oldLocation.coordinate.longitude<-180) 
    { 
     NSLog(@"old"); 
     return; 
    } 
    if(newLocation.coordinate.latitude>90 || newLocation.coordinate.latitude<-90 || newLocation.coordinate.longitude>180 || newLocation.coordinate.longitude<-180) 
    { 
     NSLog(@"new"); 
     return; 
    } 

    /////// 
    NSDate *eventDate=newLocation.timestamp; 
    NSTimeInterval eventinterval=[eventDate timeIntervalSinceNow]; 


    if (abs(eventinterval)<30.0) 
    {   
     if (newLocation.horizontalAccuracy>=0 && newLocation.horizontalAccuracy<20) 
     { 
      **//finally you are getting right updated value here....** 
     }   
    }   
} 

Answer 3

Puedes retirar esta

https://medium.com/@mizutori/make-it-even-better-than-nike-how-to-filter-locations-tracking-highly-accurate-location-in-774be045f8d6

La idea principal es Filer los datos en el método didUpdateLocation:

El método de filtro es igual que esta:

func filterAndAddLocation(_ location: CLLocation) -> Bool{ 
    let age = -location.timestamp.timeIntervalSinceNow 

    if age > 10{ 
     return false 
    } 

    if location.horizontalAccuracy < 0{ 
     return false 
    } 

    if location.horizontalAccuracy > 100{ 
     return false 
    } 

    locationDataArray.append(location) 

    return true 

}