I'm developing an iOS app which is using Google Directions API to draw routes on maps which are provided by Google Maps SDK. It works well on small distance although when I zoom the map camera very close I see that the route polylines are often getting out of the streets. When the distance is longer it's a real disaster and it's not following the streets curves if I zoom in. I'm getting the points from the overview-polyline which I receive from the Directions API but it seems like the polyline is not that poly as I want. On Android it works perfectly. Could it be that Google sends different directions to iOS than Android? Has some of you had the same problem as me?
EDIT:
-(int) requestDirecionsAndshowOnMap:(GMSMapView *)aMapView{
NSArray* mode=[[NSArray alloc]initWithObjects:@"transit",@"bicycling",@"walking",@"driving", nil];
NSString *depart=[[NSString alloc] initWithFormat:@""];
NSString *origin=[[NSString alloc] initWithFormat:@""];
NSString *destination=[[NSString alloc] initWithFormat:@""];
if (self.setLanguage)
self.setLanguage=[NSString stringWithFormat:@"language=%@",self.setLanguage];
else self.setLanguage=@"language=en";
if (searchModeOption==0) {
if (self.departDate==nil) {
self.departDate=[NSDate date];
}
depart=[NSString stringWithFormat:@"&departure_time=%i",(int)[self.departDate timeIntervalSince1970]];
}
if (self.origin) {
origin=[NSString stringWithFormat:@"origin=%@",self.origin];
}else if (self.originCoordinate.latitude && self.originCoordinate.longitude){
origin=[NSString stringWithFormat:@"origin=%f,%f",self.originCoordinate.latitude,self.originCoordinate.longitude];
}else{
NSLog(@"No origin setted");
return -1;
}
if (self.destination) {
destination=[NSString stringWithFormat:@"destination=%@",self.destination];
}else if (self.destinationCoordinate.latitude && self.destinationCoordinate.longitude){
destination=[NSString stringWithFormat:@"destination=%f,%f",self.destinationCoordinate.latitude,self.destinationCoordinate.longitude];
}else{
NSLog(@"No destination setted");
return -1;
}
NSString* URLforRequest=[[NSString stringWithFormat:@"http://maps.googleapis.com/maps/api/directions/json?%@&%@&sensor=false&%@&alternative=false&mode=%@%@",origin,destination,self.setLanguage,[mode objectAtIndex:searchModeOption],depart] stringByAddingPercentEscapesUsingEncoding: NSASCIIStringEncoding];
// NSLog(@"%@",URLforRequest);
NSURLRequest *requests = [NSURLRequest requestWithURL:[NSURL URLWithString:URLforRequest]];
[NSURLConnection sendAsynchronousRequest:requests queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error){
if (error==nil && data) {
// NSLog(@"%@",[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
directions = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves error:&error];
if (error) {
NSLog(@"%@",error);
}
NSString* status=[directions objectForKey:@"status"];
NSLog(@"Status: %@", status);
if ([status isEqualToString:@"OK"]) {
[self decodeResult];
if (aMapView)
[self showOnMap:aMapView];
}
}else NSLog(@"%@",error);
[[NSNotificationCenter defaultCenter] postNotificationName:@"Request Done" object:nil];
}];
return 0;
}
-(void) decodeResult{
self.destination=[[[[[directions objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"end_address"];
self.distance=[[[[[[[directions objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"distance"] objectForKey:@"text"] doubleValue];
self.duration=[[[[[[directions objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"duration"] objectForKey:@"text"];
//Get Array of Instructions
self.instrunctions=[[NSMutableArray alloc] init];
for (int n=0; n<[[[[[[directions objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"steps"]count]; n++) {
[self.instrunctions addObject:[[[[[[[directions objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"steps"] objectAtIndex:n] objectForKey:@"html_instructions"]];
}
//Get Overview Polyline
NSString *polystring=[[[[directions objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"overview_polyline"] objectForKey:@"points"];
NSMutableArray* decodedpolystring=[self decodePolyLine:polystring];
int numberOfCC=[decodedpolystring count];
GMSMutablePath *path = [GMSMutablePath path];
for (int index = 0; index < numberOfCC; index++) {
CLLocation *location = [decodedpolystring objectAtIndex:index];
CLLocationCoordinate2D coordinate = location.coordinate;
[path addLatitude:coordinate.latitude longitude:coordinate.longitude];
}
self.overviewPolilyne= [GMSPolyline polylineWithPath:path];
//Get Coordinates of origin and destination to be displayed on a map
float lat=[[[[[[[directions objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"]objectAtIndex:0] objectForKey:@"end_location"] objectForKey:@"lat"] floatValue];
float lng=[[[[[[[directions objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"]objectAtIndex:0] objectForKey:@"end_location"] objectForKey:@"lng"] floatValue];
CLLocationCoordinate2D tmp;
tmp.latitude=lat;
tmp.longitude=lng;
self.destinationCoordinate=tmp;
lat=[[[[[[[directions objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"]objectAtIndex:0] objectForKey:@"start_location"] objectForKey:@"lat"] floatValue];
lng=[[[[[[[directions objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"]objectAtIndex:0] objectForKey:@"start_location"] objectForKey:@"lng"] floatValue];
tmp.latitude=lat;
tmp.longitude=lng;
self.originCoordinate=tmp;
}
-(NSMutableArray *)decodePolyLine:(NSString *)encodedStr {
NSMutableString *encoded = [[NSMutableString alloc] initWithCapacity:[encodedStr length]];
[encoded appendString:encodedStr];
[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];
CLLocation *location = [[CLLocation alloc] initWithLatitude:[latitude floatValue] longitude:[longitude floatValue]];
[array addObject:location];
}
return array;
}
-(void)showOnMap:(GMSMapView *)aMapView{
GMSPolyline *polyline =self.overviewPolilyne;
polyline.strokeColor = [UIColor blueColor];
polyline.strokeWidth = 2.f;
//polyline.geodesic = YES;
polyline.map = aMapView; }
UPDATE: I had to process every step's polyline, not just the overview-polyline. Now it works perfectly.
Here's the code I'm using now:
// Get polyline
GMSMutablePath *path = [GMSMutablePath path];
NSMutableArray *polyLinesArray = [[NSMutableArray alloc] init];
int zero=0;
NSArray *steps = [[[[[directions objectForKey:@"routes"] objectAtIndex:zero] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"steps"];
for (int i=0; i<[[[[[[directions objectForKey:@"routes"] objectAtIndex:zero] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"steps"]count]; i++) {
NSString* encodedPoints =[[[steps objectAtIndex:i]objectForKey:@"polyline"]valueForKey:@"points"];
polyLinesArray = [self decodePolyLine:encodedPoints];
NSUInteger numberOfCC=[polyLinesArray count];
for (NSUInteger index = 0; index < numberOfCC; index++) {
CLLocation *location = [polyLinesArray objectAtIndex:index];
CLLocationCoordinate2D coordinate = location.coordinate;
[path addLatitude:coordinate.latitude longitude:coordinate.longitude];
if (index==0) {
[self.coordinates addObject:location];
}
}
}
self.overviewPolilyne = [GMSPolyline polylineWithPath:path];
What I basically did before was that I was getting and working only with the information I'm receiving in the routes while if you check the JSON file you're receiving from Google Directions API, you'll see that you receive much more information in the <legs> and the <steps>. This is the information we need to produce the proper results and the right polyline.
Good luck! :)
