Finding Path/Route Between two points on MapKit in iPhone

http://tricksni.blogspot.com/2012/12/finding-pathroute-between-two-points-on.html

Below is the code to finds path & draws line between two locations.

To implement below class:

_mapRecord = [[PSMapDirection alloc] initWithFrame:CGRectMake(0.0, 49.0, 320.0, 411.0)];[self.view addSubview:_mapRecord];

MapDirection.h

#import <UIKit/UIKit.h>#import <MapKit/MapKit.h>#import "RegexKitLite.h"@interface MapDirection : UIView<MKMapViewDelegate> {        MKMapView* mapView;    NSArray* routes;        BOOL isUpdatingRoutes;}-(void) showRouteFrom: (MKAnnotation*) f to:(MKAnnotation*) t;@end

MapDirection.m

#import "MapDirection.h"@interface MapDirection()-(NSArray*) calculateRoutesFrom:(CLLocationCoordinate2D) from to: (CLLocationCoordinate2D) to;-(void) centerMap;@end- (id) initWithFrame:(CGRect) frame{    self = [super initWithFrame:frame];    if (self != nil)     {        mapView = [[MKMapView alloc] initWithFrame:CGRectMake(0, 0, frame.size.width, frame.size.height)];        mapView.showsUserLocation = NO;        [mapView setDelegate:self];        [self addSubview:mapView];          }    return self;}- (NSMutableArray *)decodePolyLine: (NSMutableString *)encoded {    [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];        //printf("[%f,", [latitude doubleValue]);        //printf("%f]", [longitude doubleValue]);        CLLocation *loc = [[CLLocation alloc] initWithLatitude:[latitude floatValue] longitude:[longitude floatValue]];        [array addObject:loc];    }       return array;}-(NSArray*) calculateRoutesFrom:(CLLocationCoordinate2D) f to: (CLLocationCoordinate2D) t {    NSString* saddr = [NSString stringWithFormat:@"%f,%f", f.latitude, f.longitude];    NSString* daddr = [NSString stringWithFormat:@"%f,%f", t.latitude, t.longitude];    NSString* apiUrlStr = [NSString stringWithFormat:@"http://maps.google.com/maps?output=dragdir&saddr=%@&daddr=%@", saddr, daddr];    NSURL* apiUrl = [NSURL URLWithString:apiUrlStr];    //NSLog(@"api url: %@", apiUrl);    NSError* error = nil;    NSString *apiResponse = [NSString stringWithContentsOfURL:apiUrl encoding:NSASCIIStringEncoding error:&error];    NSString *encodedPoints = [apiResponse stringByMatching:@"points:\\\"([^\\\"]*)\\\"" capture:1L];       return [self decodePolyLine:[encodedPoints mutableCopy]];}-(void) centerMap{    MKCoordinateRegion region;    CLLocationDegrees maxLat = -90.0;    CLLocationDegrees maxLon = -180.0;    CLLocationDegrees minLat = 90.0;    CLLocationDegrees minLon = 180.0;    for(int idx = 0; idx < routes.count; idx++)    {        CLLocation* currentLocation = [routes objectAtIndex:idx];        if(currentLocation.coordinate.latitude > maxLat)            maxLat = currentLocation.coordinate.latitude;        if(currentLocation.coordinate.latitude < minLat)            minLat = currentLocation.coordinate.latitude;        if(currentLocation.coordinate.longitude > maxLon)            maxLon = currentLocation.coordinate.longitude;        if(currentLocation.coordinate.longitude < minLon)            minLon = currentLocation.coordinate.longitude;    }    region.center.latitude     = (maxLat + minLat) / 2.0;    region.center.longitude    = (maxLon + minLon) / 2.0;    region.span.latitudeDelta = 0.01;    region.span.longitudeDelta = 0.01;    region.span.latitudeDelta  = ((maxLat - minLat)<0.0)?100.0:(maxLat - minLat);    region.span.longitudeDelta = ((maxLon - minLon)<0.0)?100.0:(maxLon - minLon);    [mapView setRegion:region animated:YES];}-(void) showRouteFrom: (MKAnnotation*) f to:(MKAnnotation*) t {       if(routes)     {    [mapView removeAnnotations:[mapView annotations]];    }    [mapView addAnnotation:f];    [mapView addAnnotation:t];    routes = [self calculateRoutesFrom:f.coordinate to:t.coordinate];    NSInteger numberOfSteps = routes.count;    CLLocationCoordinate2D coordinates[numberOfSteps];    for (NSInteger index = 0; index < numberOfSteps; index++)     {        CLLocation *location = [routes objectAtIndex:index];        CLLocationCoordinate2D coordinate = location.coordinate;        coordinates[index] = coordinate;    }    MKPolyline *polyLine = [MKPolyline polylineWithCoordinates:coordinates count:numberOfSteps];    [mapView addOverlay:polyLine];    [self centerMap];}#pragma mark MKPolyline delegate functions- (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id <MKOverlay>)overlay {    MKPolylineView *polylineView = [[MKPolylineView alloc] initWithPolyline:overlay];    polylineView.strokeColor = [UIColor purpleColor];    polylineView.lineWidth = 5.0;    return polylineView;}@end

Sample Map Route for starting points - "41.967659,-87.627869" and destination points - "41.574361,-91.083069"