经纬度从位置A到位置B的路线图

Question

我正在使用地图和位置进行工作。我想要从一个地方到另一个地方有路线图。我提供的位置（目的地和来源）的纬度和经度。所以请帮我拿这张地图。

我看过谷歌地图API，但没有找到完美的答案。下面的谷歌地图API的URL

Answer 1

用来查找两个位置

http://maps.google.com/?saddr=STARTINGADDRESS&daddr=DESTINATIONADDRESS 

Answer 2

首先，你必须采取从谷歌的方向之间的路线图路线。就像这样：

NSError  *error = nil; 
NSString *directionsInJSON = [NSString stringWithContentsOfURL:[NSURL URLWithString:[NSString stringWithFormat:@"https://maps.googleapis.com/maps/api/directions/json?origin=%f,%f&destination=%f,%f&sensor=true",start.coordinate.latitude , start.coordinate.longitude , destination.coordinate.latitude, destination.coordinate.longitude]]encoding:NSUTF8StringEncoding error:&error]; 

之后，解析您在上面得到了JSON：

if (error == nil) 
{ 
    NSError *JSONError = nil; 
    SBJsonParser *JSONParser = [[SBJsonParser alloc] init]; 
    id directions = [JSONParser objectWithString:directionsInJSON error:&JSONError]; 
    if (JSONError == nil) 
    { 
     directions = (NSDictionary*)directions; 

     NSString *status = [directions objectForKey:@"status"]; 
     if ([status isEqualToString:@"OK"]) 
     { 
      NSArray   *routes = [directions objectForKey:@"routes"]; 
      NSDictionary *route = [routes objectAtIndex:0]; 
      NSDictionary *polylineOverview = [route objectForKey:@"overview_polyline"]; 

      NSString *polylinePoints = [polylineOverview objectForKey:@"points"]; 
      NSArray *decodedPolyline = [self decodePolyLine:polylinePoints]; 

      [self loadRouteWithPoints:decodedPolyline]; 
     } 
     else 
     { 
      UIAlertView *alert = [[[UIAlertView alloc] initWithTitle:@"No routes found" message:@"Sorry , we couldn't find any routes between you two." delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil] autorelease]; 
      [alert show]; 
     } 
    } 
} 
else 
{ 
    NSLog(@"error: %@",error.description); 
} 

现在，你需要这些方法：

-(void) loadRouteWithPoints:(NSArray *) routes 
{ 

    CLLocationCoordinate2D coords[[routes count]]; 
    for(int i = 0; i < routes.count; i++) 
    { 
     CLLocation* loc = (CLLocation*)[routes objectAtIndex:i];//[NSKeyedUnarchiver unarchiveObjectWithData:[routes objectAtIndex:i]]; 
     CLLocationCoordinate2D c; 
     c.latitude = loc.coordinate.latitude; 
     c.longitude = loc.coordinate.longitude; 
     coords[i] = c; 
    } 

    MKPolyline *line = [[MKPolyline polylineWithCoordinates:(CLLocationCoordinate2D*)coords count:[routes count]] retain]; 
    [self.mapsView addOverlay:line]; 
} 

和：

- (NSMutableArray *)decodePolyLine: (NSString *)encoded 
{ 
    NSInteger len = [encoded length]; 
    NSInteger index = 0; 
    NSMutableArray *array = [[[NSMutableArray alloc] init] autorelease]; 
    NSInteger lat=0; 
    NSInteger lng=0; 
    while (index < len) 
    { 
     NSInteger b; 
     NSInteger shift = 0; 
     NSInteger result = 0; 
     do 
     { 
      b = [encoded characterAtIndex:index++] - 63; 
      result |= (b & 0x1f) << shift; 
      shift += 5; 
     } while (b >= 0x20); 

     NSInteger dlat = ((result & 1) ? ~(result >> 1) : (result >> 1)); 
     lat += dlat; 
     shift = 0; 
     result = 0; 
     do 
     { 
      b = [encoded characterAtIndex:index++] - 63; 
      result |= (b & 0x1f) << shift; 
      shift += 5; 
     } while (b >= 0x20); 

     NSInteger dlng = ((result & 1) ? ~(result >> 1) : (result >> 1)); 
     lng += dlng; 
     NSNumber *latitude = [[[NSNumber alloc] initWithFloat:lat * 1e-5] autorelease]; 
     NSNumber *longitude = [[[NSNumber alloc] initWithFloat:lng * 1e-5] autorelease]; 
     CLLocation *loc  = [[[CLLocation alloc] initWithLatitude:[latitude floatValue] longitude:[longitude floatValue]] autorelease]; 
     [array addObject:loc]; 
    } 

    return array; 
} 

瞧！

干杯！