-(void) loadRoute{NSString* filePath = [[NSBundle mainBundle] pathForResource:@”route” ofType:@”csv”];NSString* fileContents = [NSString stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:nil];NSArray* pointStrings = [fileContents componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

// while we create the route points, we will also be calculating the bounding box of our route// so we can easily zoom in on it.MKMapPoint northEastPoint;MKMapPoint southWestPoint; 

// create a c array of points.MKMapPoint* pointArr = malloc(sizeof(CLLocationCoordinate2D) * pointStrings.count);

for(int idx = 0; idx < pointStrings.count; idx++){// break the string down even further to latitude and longitude fields.NSString* currentPointString = [pointStrings objectAtIndex:idx];NSArray* latLonArr = [currentPointString componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@","]];

CLLocationDegrees latitude = [[latLonArr objectAtIndex:0] doubleValue];CLLocationDegrees longitude = [[latLonArr objectAtIndex:1] doubleValue];

// create our coordinate and add it to the correct spot in the arrayCLLocationCoordinate2D coordinate = CLLocationCoordinate2DMake(latitude, longitude);

MKMapPoint point = MKMapPointForCoordinate(coordinate);

//// adjust the bounding box//

// if it is the first point, just use them, since we have nothing to compare to yet.if (idx == 0) {northEastPoint = point;southWestPoint = point;}else{if (point.x > northEastPoint.x)northEastPoint.x = point.x;if(point.y > northEastPoint.y)northEastPoint.y = point.y;if (point.x < southWestPoint.x)southWestPoint.x = point.x;if (point.y < southWestPoint.y)southWestPoint.y = point.y;}

pointArr[idx] = point;

}

// create the polyline based on the array of points.self.routeLine = [MKPolyline polylineWithPoints:pointArr count:pointStrings.count];

_routeRect = MKMapRectMake(southWestPoint.x, southWestPoint.y, northEastPoint.x -southWestPoint.x, northEastPoint.y - southWestPoint.y);

// clear the memory allocated earlier for the pointsfree(pointArr);

}

[self.mapView addOverlay:self.routeLine];

- (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id )overlay{MKOverlayView* overlayView = nil;

if(overlay == self.routeLine){//if we have not yet created an overlay view for this overlay, create it now.if(nil == self.routeLineView){self.routeLineView = [[[MKPolylineView alloc] initWithPolyline:self.routeLine] autorelease];self.routeLineView.fillColor = [UIColor redColor];self.routeLineView.strokeColor = [UIColor redColor];self.routeLineView.lineWidth = 3;}

overlayView = self.routeLineView;

}

return overlayView;

}