I found current location using (CLLocationManager startUpdatingLocation) this method. How long it takes to find current location ?(In minutes).
Because i want to set time out for CLLocationManger classes to stop updatinglocation.
Can anyone help me ? Thanks in advance.......
My location manager desiredAccuracy should be kCLLocationAccuracyBest and distancefilter should be kCLDistanceFilterNone.
If you started your stopwatch at moment when you entered into tunnel, you will get your gps coordinates immediately after you exit the tunnel.
Related
I am working in the cllocation manager and get the current location of user but unable to find the user status like user is in running position or stop position . So please help me , How can get its corrent status when user walking programmatically in iphone.
Use the speed attribute of CLLocation, asumimg GPS enabled and set to best accuracy.
If (loc.speed > 7/3.6) then running
walking: < 6 km/h
stopped is more difficult: no location update (measured with a timer)
But you cannot distinguish between "stopped" and "no GPS available" (e.g in underground, or indoors). That would need the acceleration sensor, if the state needs to be in real time.
I am trying to get Altitude of my location in my application. But every time I try altitude property of CLLocation object I am getting 0.00 as result.
I googled for my query and I got a similar question here and here. This link is saying that if I access CLLocation with wifi or cell tower it will be null. Even if I try to set desireAccuracy to best than even it don't make sure that app will use GPS. It is also saying that if I am indoor that I won't be able to access GPS.
I many cases it its not sure that app will use GPS only. I want some way for getting Altitude from wifi or cell tower too. For that I googled more and I got Google Earth API but I think this is for Microsoft .net technology only.
Now according to this situation I think for a solution I can create a web service in Microsoft Technology and pass my location there and I can get altitude as response but I don't want to do this.
Can anyone suggest me how to get my location's altitude from ios. Is there any way available or not? If yes than please navigate me in right direction.
Thanks in advance.
Edit1
I used CLLocationManager for updating location and when I get my location I need altitude.
Edit2
According to #fishinear's answer I tried following code:
- (void)viewDidLoad
{
[super viewDidLoad];
manager = [[CLLocationManager alloc] init];
[manager setDesiredAccuracy:kCLLocationAccuracyBestForNavigation];
[manager setDistanceFilter:kCLDistanceFilterNone];
[manager setDelegate:self];
[manager startUpdatingLocation];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {
if ([newLocation verticalAccuracy] >= 0) {
NSLog(#"Altitude = %lf",newLocation.altitude);
}
NSLog(#"Vertical Accuracy : %lf",newLocation.verticalAccuracy);
}
verticalAccuracy is always -1. It is not changing even after running the app to last 30 Mins. I am runnin ios 4.3.2 on my 3GS. I am indoor so I think it is not accessing GPS using this code even.
To answer your original question:
GPS will always be used if you set desiredAccuracy to Best or BestForNavigation, and distanceFilter to kCLDistanceFilterNone when configuring the CLLocationManager. You will then also get altitude values in the CLLocation event.
However, it takes a short while before the GPS has "locked in" to enough satelites to be able to report the altitude. During that time it will report CLLocation events without altitude values. Therefore, you should ignore the first couple of events until the verticalAccuracy value is good enough for you. Also, check the timestamp, because sometimes the first CLLocation event is an old one.
See Android - Get Altitude By Longitude and Latitude? there is an Android solution but it is easily adaptable to iOS.
The answer is to use the USGS Elevation Query Web Service
From the top answer there, basically you just send an HTML Web request to:
http://gisdata.usgs.gov/xmlwebservices2/elevation_service.asmx/getElevation?X_Value=" +
String.valueOf(longitude) +
"&Y_Value=" + String.valueOf(latitude)
+ "&Elevation_Units=METERS&Source_Layer=-1&Elevation_Only=true";
Then you can parse out the response text from between the <double>...</double> tags
Edit:
It looks like you might be trying to get elevation outside the United States.
Google Maps API does provide an Elevation service and documentation at https://developers.google.com/maps/documentation/javascript/elevation
In order to conserve battery, I monitor location updates to see if the user has been stationary for a period of time; if so, I then downgrade the CLLocationManager from its main settings of kCLLocationAccuracyBestForNavigation and kCLDistanceFilterNone (maximum settings) to monitoring significant location changes only.
The trouble is, it doesn't work: after calling startMonitoringSignificantLocationChanges, the location updates continue to pour in at a high rate as they did prior to the call.
How do you wind activity down and then back up again?
Update: this code answers the question:
//Set
if ( shouldMonitorSignificantChangeUpdates ) {
NSLog(#"Entering -> significant change mode");
[self.locationManager stopUpdatingLocation];
[self.locationManager startMonitoringSignificantLocationChanges]; //aka stop monitoring every location change
} else {
NSLog(#"Exiting <- significant change mode");
[self.locationManager stopMonitoringSignificantLocationChanges]; //aka begin monitoring every location change
[self.locationManager startUpdatingLocation];
}
From the docs:
startMonitoringSignificantLocationChanges does not rely on the value in the distanceFilter property to generate events
Instead of using startMonitoringSignificantLocationChanges, use a timer to stop and start the location updates.
You could also try turning off location updates, then turning it back on using startMonitoringSignificantLocationChanges. Don't forget that this will make the system launch your app after it's been terminated when it detects a significant location change. It doesn't look like that's what you really want.
Actually the code as edited in the question does work. It allows the system to go back and forth from "constant stream of locations" to "occasional updates" as desired.
I think my initial testing was simply not aggressive enough and the docs don't really discuss using both techniques, instead imagining an app which needs either navigation or significant changes only.
I having some problem on the iPhone/iPad compass development.
The trueHeading taken from the CLHeading alway give me the '-1' value, I'm stuck here. Here is my code:
self.locationManager = [[[CLLocationManager alloc] init] autorelease];
self.locationManager.desiredAccuracy = kCLLocationAccuracyBest;
self.locationManager.delegate = self;
self.locationManager.headingFilter = 0.5; //1 degrees
[self.locationManager startUpdatingHeading];
I also found out something, that is when I on the map app or the compass app which has use the location stuff, the trueHeading value suddenly read correct. I wonder what is the cause, any idea? It happen on both iPhone4 and on the iPad.
It also happen whenever I off the Location Services in settings and re-enable it, it will become unable to read the correct trueHeading value, i wonder because the location services cannot be enable by the app I creating?
anyway, thank in advance
---My Solution---
see below.
to avoid the heading keep returning -1.000000, not JUST run startUpdatingHeading but run startUpdatingLocation together, this helps.
Try using this...
CLLocationManager *locationManager = [[CLLocationManager alloc] init];
locationManager.delegate=self;
locationManager.desiredAccuracy=kCLLocationAccuracyBestForNavigation;
// Start heading updates.
if (locationManager.headingAvailable && locationManager.locationServicesEnabled)
{
locationManager.headingFilter = kCLHeadingFilterNone;
[locationManager startUpdatingHeading];
}
and after doing this CLLocationManager delegate methods calls
- (void)locationManager:(CLLocationManager *)manager didUpdateHeading:(CLHeading *)newHeading {
// Use the true heading if it is valid.
[lblAccuracy setText:[NSString stringWithFormat:#"%.1fmi",newHeading.headingAccuracy]];
}
But this coding works on device not in simulator...
Happy coding..
---My Solution---
What I did was, add in the [self.locationManager startUpdatingLocation] to before or after the [self.locationManager startUpdatingHeading]; (when Location Services is off & re-enable from the Settings). I'm not sure this is a good solution, but this is what I did to make it work, if you have any better solution please share.
I had some trouble with the location manager myself and found out that for me it helped to unplug the iPhone from the computer when testing. Somehow the calibration alert only popped up after unplugging the iPhone.
I had this same problem. I moved startUpdatingHeading into a button action, then moved it back to where the CLLocationManager is allocated -- where it had been working fine -- and it started returning only -1.
I rebooted my iPad and it started working again. Hopefully it stays that way.
Edit: Nope, it didn't stay that way. I had to use startUpdatingLocation too. Won't this wear down the battery though? I set desiredAccuracy to kCLLocationAccuracyThreeKilometers, because I am not using location data anyway.
A TRUE reading requires knowing the magnetic variation for the place where you are using the compass. From the previous discussion, it appears to be that the function that corrects the true direction from magnetic direction needs your location for obtaining the variation value. If you don't like to use the location GPS information in your code, I suggest reading the magnetic reading and correct the value by yourself. You need to obtain the variation for the desired location first then apply the following formula: T=M ± V, where T is the true direction, M is the compass magnetic reading and V is the variation. Use "+" for East and "-" for West. I found the allowing web site provide the variation(magnetic declination) for any needed location: http://www.geomag.nrcan.gc.ca/calc/mdcal-eng.php.
When location services are off, the didUpdateHeading delegate method returns only the magnetic heading. You can use it according to your needs. According to Apple docs..
To begin the delivery of heading-related events, assign a delegate to
the location manager object and call its startUpdatingHeading method.
If location updates are also enabled, the location manager returns
both the true heading and magnetic heading values. If location updates
are not enabled, the location manager returns only the magnetic
heading value.
Working on this problem now. I can get updates from Core Motion when I use SpriteKit. It's about being able to call a function continuously like once a frame (1/60th of a second) or every few frames. Without using SpriteKit, the documentation says to invoke the updates within a closure, which I assume will be on their own thread and up to you to release.
There's an algorithm for converting the magnetometer readings to actual degrees relative to true north. Picture a graph that looks like the time domain function of alternating current and you'll see that interpolating the data is a simple matter of applying Maxwell's equations. Here's an example on honeywell
when i run my application its get my location(Lat,logi) both new and old location.But i want to set oldlocation as new location when my application run first time.Because i want to calculate distance travel.
If i run my application it takes oldlocation where last location it get (saw distance travel 1 Km when i start application first time)
Hope u Understand
Thanks
You can try to make some flag to indicate the first launching of your app. And then store this flag in NSUserDefaults. For example, if you cannot find your flag after launch, you show alert like "would you like to use your current location as start location?" if user choose YES, so you will update location and store it in the userDefaults. This is a persistent storage. Oh, perhaps, it even will be better to store not flag, but your start location coordinates.