I am attempting to modify our app from using MKReverseGeocoder to CLGeocoder for devices running iOS 5, but I'm getting different results from the two classes. Specifically, when doing a reverse geocode with this coordinate:
(47.643126, -122.204037)
I get this from MKReverseGeocoder:
10210 NE Points Dr
Kirkland, Washington 98033
but I get this from CLGeocoder:
9601-10267 NE Points Dr
Kirkland, Washington 98033
The second value is much less specific than the first and therefore much less useful. The solution for now is to just use MKReverseGeocoder, but at some point we'll be forced to switch.
Q: Any idea how to improve the results from CLGeocoder?
Thanks,
David
update their database. In short their data is less specific/accurate so there is nothing you can do apart from accept their less accurate data
when i try to get the current location using
CLLocationCoordinate2D CurrentLocation;
CurrentLocation = map.userLocation.coordinate;
i get the follwoing values:
CurrentLocation.latitude= -180.000000;
CurrentLocation.longitude= -180.000000;
and it is not my location at all.
do you know what is missing in this?
Firstly, make sure that you have set the mapView's showUserLocation to TRUE.
Secondly, check that the value is not nil, as the mapView needs to locate the user first, and that takes a few seconds.
I have been working on a maps application (iphone) originally I had my annotations set up to pull XML from google using their Places API. I'm having 3 issues.
For my annotation info, I was going
off of an example from Zen
(http://www.zen-sign.com/finding-business-listings-and-displaying-with-mapkit-part-1/
) and he has it set up to do it by
keyword, which wasn't really
necessary for me ( but I used it
anyway just to get a feel for
getting the annotations) in the
parser header he has:
-(void) getBusinessListingsByKeyword:(NSString*)keyword atLat:(float)lat atLng:(float)lng;
and in the the viewdidload of his
view controller
[locationsMap findLocationsByKeyword:#"Apple" ];
I'm not sure how to move from the
keyword parse version used in zen to
something that just does it
automatically (in the parser object- without the viewdidload in a different view controller if possible).
Any advice on what to read/watch or
sample code much appreciated
For places information
Google isn't the only kid on the
block and XML I hear comes in second
to JSON. So I wanted to know what
the best practice was for map
annotations made from business
information: JSON or XML?
The other issue I was having was
only getting 10 annotations (I want
to get 50 or more). So on top of
your advice on using XML or JSON.
How to I increase the amount of
annotations I'm getting.
Sorry for making this 3 parts but again any tutorials (text of video) would be very helpful. (So far I've watched hegarty from Stanford, Larson from MATC)
First
Don't know what you mean by automaticaly. But if you want to launch the map on users current location here you have two methods you can use:
-(IBAction)goToCurrentLocation{
CLLocation *location = [[CLLocation alloc]
initWithLatitude:myMap.userLocation.coordinate.latitude
longitude:myMap.userLocation.coordinate.longitude];
[self setCurrentLocation:location];
}
- (void)setCurrentLocation:(CLLocation *)location {
MKCoordinateRegion region = {{0.0f, 0.0f}, {0.0f, 0.0f}};
region.center = location.coordinate;
region.span.longitudeDelta = 0.15f;
region.span.latitudeDelta = 0.15f;
[self.myMap setRegion:region animated:YES];
}
Second. I don't know what are the best practicies but I used json with this jeson parser for my app ijustmadelove
Three. There is no problem in getting more then 10 annotations on the map. You have to have an error or a limitation in your code.
i'm drawing polyline on MapView using "google direction API" and getting success in it.But the thing is that it draws straight line between two locations(with their longitude and latitude).I don't know how to draw line effectively like shown by google maps,when we click "get directions" between two locations.
I suggest taking a look at an SDK like CloudMade, this makes it very easy to implement custom maps and route's, you'll be able to draw a route between two locations within about 10 minutes of installing the SDK. Here is a quick example to get you started if you go down this route, excuse the pun.
CLLocationCoordinate2D initLocation;
initLocation.longitude = -0.127523;
initLocation.latitude = 51.51383;
CLLocationCoordinate2D destination;
destination.longitude = -0.125;
destination.latitude = 51;
TokenManager* tokenManager = [[TokenManager alloc] initWithApikey:#"YOUR API KEY"];
CMRoutingManager *routeManager = [[CMRoutingManager alloc] initWithMapView:mapView tokenManager:tokenManager];
[routeManager findRouteFrom:initLocation to:destination onVehicle:CMVehicleWalking];
You can find more information here in the documentation. Another alternative would be to use route-me which would allow you to choose from the following map sources:
OpenStreetMap, Microsoft VirtualEarth, CloudMade, OpenAerialMap, OpenCycleMap, SpatialCloud, and two offline, database-backed formats (DBMap and MBTiles)
Although personally i do not have any experience with route-me, so can't point you in the right direction to get started.
If you are adement on sticking with MKMapView, this blog post will get your started in the right direction.
I keep getting this randomly when I run my gps app I'm building. It doesn't happen everytime, and the coordinates passed in are always valid (i nslog them). Is there documentation for these somewhere?
EDIT:
CLLocationCoordinate2D coord = CLLocationCoordinate2DMake(locManager.location.coordinate.latitude, locManager.location.coordinate.longitude);
geocoder1 = [[MKReverseGeocoder alloc] initWithCoordinate:coord];
geocoder1.delegate = self;
[geocoder1 start];
and then about half the time it returns an error. I tried releasing and re-assigning the geocoder if there was an error, but that didn't help. Only thing that did was restarting the app.
In "MKTypes.h" in the MapKit framework, the following is defined:
Error constants for the Map Kit framework.
enum MKErrorCode {
MKErrorUnknown = 1,
MKErrorServerFailure,
MKErrorLoadingThrottled,
MKErrorPlacemarkNotFound,
};
...
MKErrorPlacemarkNotFound
The specified placemark could not be found.
This sounds like you are referencing some unknown placemark in your code? Or it could be that Google doesn't have a name for the position you are passing - however valid the coordinates may be.
I've met and solved this issue recently. In my case, when Apple Map cannot find any result for a query, it sometimes will just throw this this "MKErrorDomain = 4" error. So I ended up just treat this as "result not found".
It was painstaking to find this out, MapKit needs a better Error handling system.
I've been hitting this error repeatedly, and was unable to figure out how to make it stop; but I finally found an end-run around the whole issue that works quite well, and only takes a little more work: Don't use Apple's MKReverseGeocoder at all -- instead, directly call Google's reverse-geocoding API (this is apparently the same service that MKReverseGeocoder does behind the scenes). You can get back either JSON or XML (your preference), which you will then have to parse, but that isn't too hard.
For example, since my app is using ASIHTTPRequest, this is what it looks like (although this would also be easy to do with do with Apple's native APIs such as NSURLConnection):
#pragma mark -
#pragma mark CLLocationManagerDelegate
- (void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation
{
// Be careful: My code is passing sensor=true, because I got the lat/long
// from the iPhone's location services, but if you are passing in a lat/long
// that was obtained by some other means, you must pass sensor=false.
NSString* urlStr = [NSString stringWithFormat:
#"http://maps.googleapis.com/maps/api/geocode/xml?latlng=%f,%f&sensor=true",
newLocation.coordinate.latitude, newLocation.coordinate.longitude];
NSURL* url = [NSURL URLWithString:urlStr];
self.reverseGeocoderRequest = [ASIHTTPRequest requestWithURL:url];
self.reverseGeocoderRequest.delegate = self;
[self.reverseGeocoderRequest startAsynchronous];
}
By the way, Google's API has rules, just like Apple's does. Make sure you read the docs, especially regarding quotas.
I'm running into the same thing (the exact same code randomly fails sometimes) and I think I've found the answer. From Apple's developer docs: "Each Map Kit application has a limited amount of reverse geocoding capacity, so it is to your advantage to use reverse geocode requests sparingly."
So my theory is, we're getting rate-limited... since no other variables are changing (i.e. my code isn't changing, I'm running it on the simulator so the location of the device isn't changing, etc.) I think this must be the only remaining reason.
I just got done with a lot of research on this problem and it seems to be outside of our hands. I checked the developer forums as well as all around Stack and elsewhere and no one has a solution other than using a different service. There is a pretty good thread at https://devforums.apple.com/message/154126 on the subject.
Some people find the error after a certain time, I just find it to be out for a while and then comes back. I looked at the "Current Address" sample code and I couldn't see how I might have messed up. I ran the sample code and sure enough, it was NSLogging errors instead of returning a location.
This link has some code using Google's reverse geocoder: http://www.iphonedevsdk.com/forum/iphone-sdk-development/31883-pbrequestererrordomain-errors-reverse-geocoding.html#post155793
Actually, I am running into this problem as well. Code is extremely compact
//1. ask map for current coords
CLLocationCoordinate2D userLocation;
userLocation.latitude = [[_theMapView.userLocation location] coordinate].latitude;
userLocation.longitude = [[_theMapView.userLocation location] coordinate].longitude;
NSLog(#"%f, %f",userLocation.latitude,userLocation.longitude);
//2. reverse geocode coords
MKReverseGeocoder *reverseGeocoder = [[MKReverseGeocoder alloc]
initWithCoordinate:userLocation];
[reverseGeocoder setDelegate:self];
[reverseGeocoder start];
and later simply NSLog the error in the fail delegate method. It works the first time or two, then stops working