-(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 array
CLLocationCoordinate2D 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 points
free(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;


}