How to get route length in mapKit - ios

Question

I'm using mapKit to draw a route from point to point. I did it.
But i want to get route length NOT the distance as straight line.
nextView.startPoint = [NSString stringWithFormat:#"%f,%f", userLatitude , userLongitude];
nextView.endPoint = [NSString stringWithFormat:#"%f,%f", 30.793636, 31.009641];
[diretions loadWithStartPoint:startPoint endPoint:endPoint options:options];
Aloso i want to give it a mid point to path through.

Answer 1

To do that you are going to have to use a directions API, preferably Google Directions API. You should look at that link and read it through, Apple does not have a built in direction API. You can send it a request and ask for JSON response, I would use AFNetworking to make like easier (on Github) and JSONKit also on Github for that. Then send a request and parse the JSON response. In the response you need the encoded points, which is a set of many coordinates that basically traces the route. You would then need to display that on an overlay. Here is some sample code, but before you copy and paste this in make sure you read the GDirections API Site, you will understand everything MUCH easier and can learn how to do more:
// DRAG IN AFNETWORKING FILES AND JSON KIT FILES TO YOUR PROJECT AND ALSO IMPORT THE MAP KIT AND CORE LOCATION FRAMEWORKS
// IMPORT FILES
#import "StringHelper.h"
#import "JSONKit.h"
#import "AFJSONRequestOperation.h"
#import "AFHTTPClient.h"
#import <MapKit/MapKit.h>
#import <CoreLocation/CoreLocation.h>
// DECLARE MUTABLE ARRAY IN .H:
NSMutableArray *_path;
// ADD THIS CODE TO WHEN YOU WANT TO REQUEST FOR DIRECTIONS
AFHTTPClient *_httpClient = [AFHTTPClient clientWithBaseURL:[NSURL URLWithString:#"http://maps.googleapis.com/"]];
[_httpClient registerHTTPOperationClass: [AFJSONRequestOperation class]];
[_httpClient setDefaultHeader:#"Accept" value:#"application/json"];
NSMutableDictionary *parameters = [[NSMutableDictionary alloc] init];
[parameters setObject:[NSString stringWithFormat:#"%f,%f", location.coordinate.latitude, location.coordinate.longitude] forKey:#"origin"];
[parameters setObject:[NSString stringWithFormat:#"%f,%f", location2.coordinate.latitude, location2.coordinate.longitude] forKey:#"destination"];
[parameters setObject:#"false" forKey:#"sensor"];
[parameters setObject:#"driving" forKey:#"mode"];
[parameters setObject:#"metric" forKey: #"units"];
NSMutableURLRequest *request = [_httpClient requestWithMethod:#"GET" path: #"maps/api/directions/json" parameters:parameters];
request.cachePolicy = NSURLRequestReloadIgnoringLocalCacheData;
AFHTTPRequestOperation *operation = [_httpClient HTTPRequestOperationWithRequest:request success:^(AFHTTPRequestOperation *operation, id responseObject) {
NSInteger statusCode = operation.response.statusCode;
if (statusCode == 200) {
[self parseResponse:responseObject];
}
} failure:^(AFHTTPRequestOperation *operation, NSError *error) { }];
[_httpClient enqueueHTTPRequestOperation:operation];
// NOW ADD THE PARSERESPONSE METHOD
- (void)parseResponse:(NSDictionary *)response {
NSString *status = [response objectForKey: #"status"];
NSArray *routes = [response objectForKey:#"routes"];
NSDictionary *routePath = [routes lastObject];
if (routePath) {
NSString *overviewPolyline = [[routePath objectForKey: #"overview_polyline"] objectForKey:#"points"];
_path = [self decodePolyLine:overviewPolyline];
NSInteger numberOfSteps = _path.count;
CLLocationCoordinate2D coordinates[numberOfSteps];
for (NSInteger index = 0; index < numberOfSteps; index++) {
CLLocation *location = [_path objectAtIndex:index];
CLLocationCoordinate2D coordinate = location.coordinate;
coordinates[index] = coordinate;
}
polyLine = [MKPolyline polylineWithCoordinates:coordinates count:numberOfSteps];
[self.mapView addOverlay:polyLine];
}
}
// IMPLEMENTING THE DECODEPOLYLINE METHOD:
-(NSMutableArray *)decodePolyLine:(NSString *)encodedStr {
NSMutableString *encoded = [[NSMutableString alloc] initWithCapacity:[encodedStr length]];
[encoded appendString:encodedStr];
[encoded replaceOccurrencesOfString:#"\\\\" withString:#"\\"
options:NSLiteralSearch
range:NSMakeRange(0, [encoded length])];
NSInteger len = [encoded length];
NSInteger index = 0;
NSMutableArray *array = [[NSMutableArray alloc] init];
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];
NSNumber *longitude = [[NSNumber alloc] initWithFloat:lng * 1e-5];
CLLocation *location = [[CLLocation alloc] initWithLatitude:[latitude floatValue] longitude:[longitude floatValue]];
[array addObject:location];
}
return array;
}
// IMPLEMENTING THE VIEWFOROVERLAY DELEGATE METHOD (MAKE SURE TO SET YOUR MAP VIEW'S DELEGATE TO SELF OR THIS WONT GET CALLED)
- (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id <MKOverlay>)overlay {
MKPolylineView *polylineView = [[MKPolylineView alloc] initWithPolyline:overlay];
polylineView.strokeColor = [UIColor blueColor];
polylineView.lineWidth = 5.0;
polylineView.alpha = 0.7;
return polylineView;
}
And that should get your directional routes up and running!