PolylineDemo

Track user location and draw a polyline view on MKMapView.

Requirements

• MapKit.framework
• CoreLocation.framework

Examples

- (void)configureRoutes
{
    // define minimum, maximum points
	MKMapPoint northEastPoint = MKMapPointMake(0.f, 0.f); 
	MKMapPoint southWestPoint = MKMapPointMake(0.f, 0.f); 
	
	// create a c array of points. 
	MKMapPoint* pointArray = malloc(sizeof(CLLocationCoordinate2D) * _points.count);
    
	// for(int idx = 0; idx < pointStrings.count; idx++)
    for(int idx = 0; idx < _points.count; idx++)
	{        
        CLLocation *location = [_points objectAtIndex:idx];  
        CLLocationDegrees latitude  = location.coordinate.latitude;
		CLLocationDegrees longitude = location.coordinate.longitude;		 
        
		// create our coordinate and add it to the correct spot in the array 
		CLLocationCoordinate2D coordinate = CLLocationCoordinate2DMake(latitude, longitude);
		MKMapPoint point = MKMapPointForCoordinate(coordinate);
		
		// 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;
		}
        
		pointArray[idx] = point;        
	}
	
    if (self.routeLine) {
        [self.mapView removeOverlay:self.routeLine];
    }
    
    self.routeLine = [MKPolyline polylineWithPoints:pointArray count:_points.count];
    
    // add the overlay to the map
	if (nil != self.routeLine) {
		[self.mapView addOverlay:self.routeLine];
	}
    
    // clear the memory allocated earlier for the points
	free(pointArray);	
    
    double width = northEastPoint.x - southWestPoint.x;
    double height = northEastPoint.y - southWestPoint.y;
     
    _routeRect = MKMapRectMake(southWestPoint.x, southWestPoint.y, width, height);    	
     
    // zoom in on the route. 
    [self.mapView setVisibleMapRect:_routeRect];
}

// MKMapViewDelegate methods
- (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id <MKOverlay>)overlay
{
	MKOverlayView* overlayView = nil;
	
	if(overlay == self.routeLine)
	{
		// if we have not yet created an overlay view for this overlay, create it now. 
        if (self.routeLineView) {
            [self.routeLineView removeFromSuperview];
        }
        
        self.routeLineView = [[MKPolylineView alloc] initWithPolyline:self.routeLine];
        self.routeLineView.fillColor = [UIColor redColor];
        self.routeLineView.strokeColor = [UIColor redColor];
        self.routeLineView.lineWidth = 10;
        
		overlayView = self.routeLineView;		
	}
	
	return overlayView;
}