Beispiel

NSMutableArray* points = [[NSMutableArray alloc] initWithCapacity:coordinates.count];
		
for(int idx = 0; idx < coordinates.count; idx++)
{
	Koordinate* coord = (Koordinate*)[coordinates objectAtIndex:idx];

         CLLocation* currentLocation = [[[CLLocation alloc] initWithLatitude:coord.coordinate.latitude longitude:coord.coordinate.longitude] autorelease];
	[points addObject:currentLocation];

}
		
// create our route layer view, and initialize it with the map on which it will be rendered. 
routeView = [[CSMapRouteLayerView alloc] initWithRoute:points mapView:mapView];

CSMapRouteLayerView.h

//
//  CSMapRouteLayerView.h
//  mapLines
//
//  Created by Craig on 4/12/09.
//  Copyright 2009 __MyCompanyName__. All rights reserved.
//

#import <Foundation/Foundation.h>
#import <MapKit/MapKit.h>

@interface CSMapRouteLayerView : UIView <MKMapViewDelegate>
{
	MKMapView* _mapView;
	NSArray* _points;
	UIColor* _lineColor;
}

-(id) initWithRoute:(NSArray*)routePoints mapView:(MKMapView*)mapView;

@property (nonatomic, retain) NSArray* points;
@property (nonatomic, retain) MKMapView* mapView;
@property (nonatomic, retain) UIColor* lineColor; 

@end

CSMapRouteLayerView.m

//
//  CSMapRouteLayerView.m
//  mapLines
//
//  Created by Craig on 4/12/09.
//  Copyright 2009 __MyCompanyName__. All rights reserved.
//

#import "CSMapRouteLayerView.h"


@implementation CSMapRouteLayerView
@synthesize mapView   = _mapView;
@synthesize points    = _points;
@synthesize lineColor = _lineColor; 

-(id) initWithRoute:(NSArray*)routePoints mapView:(MKMapView*)mapView
{
	self = [super initWithFrame:CGRectMake(0, 0, mapView.frame.size.width, mapView.frame.size.height)];
	[self setBackgroundColor:[UIColor clearColor]];
	
	[self setMapView:mapView];
	[self setPoints:routePoints];
	
	// determine the extents of the trip points that were passed in, and zoom in to that area. 
	CLLocationDegrees maxLat = -90;
	CLLocationDegrees maxLon = -180;
	CLLocationDegrees minLat = 90;
	CLLocationDegrees minLon = 180;
	
	for(int idx = 0; idx < self.points.count; idx++)
	{
		CLLocation* currentLocation = [self.points 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;
	}
	
	MKCoordinateRegion region;
	region.center.latitude     = (maxLat + minLat) / 2;
	region.center.longitude    = (maxLon + minLon) / 2;
	region.span.latitudeDelta  = maxLat - minLat;
	region.span.longitudeDelta = maxLon - minLon;
	
	self.userInteractionEnabled = NO;
	
	[self.mapView setRegion:region];
	[self.mapView setDelegate:self];
	[self.mapView addSubview:self];
	
	return self;
}


- (void)drawRect:(CGRect)rect
{
	// only draw our lines if we're not int he moddie of a transition and we 
	// acutally have some points to draw. 
	if(!self.hidden && nil != self.points && self.points.count > 0)
	{
		CGContextRef context = UIGraphicsGetCurrentContext(); 
		
		if(nil == self.lineColor)
			self.lineColor = [UIColor blueColor];
		
		CGContextSetStrokeColorWithColor(context, self.lineColor.CGColor);
		CGContextSetRGBFillColor(context, 0.8, 0.8, 0.8, 0.7);

		// Draw them with a 2.0 stroke width so they are a bit more visible.
		CGContextSetLineWidth(context, 2.0);
		
		for(int idx = 0; idx < self.points.count; idx++)
		{
			CLLocation* location = [self.points objectAtIndex:idx];
			CGPoint point = [_mapView convertCoordinate:location.coordinate toPointToView:self];
			
			if(idx == 0)
			{
				// move to the first point
				CGContextMoveToPoint(context, point.x, point.y);
			}
			else
			{
				//CGContextAddQuadCurveToPoint(context, point.x, point.y, point.x, point.y);
				CGContextAddLineToPoint(context, point.x, point.y);
			}
		}

		CGContextFillPath(context);
	}
}


#pragma mark mapView delegate functions
- (void)mapView:(MKMapView *)mapView regionWillChangeAnimated:(BOOL)animated
{
	// turn off the view of the route as the map is chaning regions. This prevents
	// the line from being displayed at an incorrect positoin on the map during the
	// transition. 
	self.hidden = YES;
}
- (void)mapView:(MKMapView *)mapView regionDidChangeAnimated:(BOOL)animated
{
	// re-enable and re-poosition the route display. 
	self.hidden = NO;
	[self setNeedsDisplay];
}

-(void) dealloc
{
	[_points release];
	[_mapView release];
	[super dealloc];
}

@end