I have some addresses with gps data in my database. Now i want to use them in my iOS app, to make a lookup which of these addresses are in a radius of 30km from the phone location.
How can i do this?
I've found the answer.
You can use the CLLocation Framework with this function.
https://developer.apple.com/library/ios/#documentation/CoreLocation/Reference/CLLocation_Class/CLLocation/CLLocation.html#//apple_ref/occ/instm/CLLocation/distanceFromLocation:
Also you can do this with MySQL.
Look at this page, for more information.
http://www.scribd.com/doc/2569355/Geo-Distance-Search-with-MySQL
Related
hai
Can we know current location without using gps? Is it possible?
The iPhone SDK has a framework that automatically utilizes the proper mechanism for determining location based on how accurate the result needs to be. Apple has a good article discussing these different methods of locating a device.
Also, here is a good starting point for learning about programming with Location Services.
Furthermore, you can dive right into the CoreLocation framework documentation and learn about everything you can do using Location Services on iOS.
Yes, CoreLocation can triangulate your position via nearby cell phone towers, but the position won't be as accurate as with GPS. Also, it can get your location via nearby WLANs, but this is even less reliable.
Core Location does what you want (by using Wi-Fi triangulation). Check out the documentation of CLLocationManager
Try this
map.showsUserLocation = YES;
map is my MKMapView Object.
Well thats kind of a very broad and very general question. If you are talking cell phones you can use three tower triangulation which is good when you are hitting three towers all at once, but if you are only hitting one the error can be up to a few kilometers.
Now if you are talking internet accessing devices (ie something with an IP address) again things get dicey. If you are using a stationary access point you will get a close approximation using nearest known Hubs with the IP range the device is in. Mobile devices with IPs are really hard to pinpoint.
More links
http://mithin.in/2009/06/22/using-iphone-sdk-mapkit-framework-a-tutorial
http://www.icodeblog.com/2009/12/22/introduction-to-mapkit-in-iphone-os-3-0-part-2/
and step by step guide.
http://gigaom.com/apple/iphone-dev-sessions-finding-your-way-with-mapkit/
To add to #Jenifer's answer
showsUserLocation
Discussion
This property does not indicate
whether the user’s position is
actually visible on the map, only
whether the map view is allowed to
display it. To determine whether the
user’s position is visible, use the
userLocationVisible property. The
default value of this property is NO.
Setting this property to YES causes
the map view to use the Core Location
framework to find the current
location. As long as this property is
YES, the map view continues to track
the user’s location and update it
periodically.
Core Location Framework
The Core Location framework lets you
determine the current location or
heading associated with a device. The
framework uses the available hardware
to determine the user’s position and
heading. You use the classes and
protocols in this framework to
configure and schedule the delivery of
location and heading events. You can
also use it to define geographic
regions and monitor when the user
crosses the boundaries of those
regions.
If you want to know How does the Core Location do this
It actually uses several mechanisms.
GPS
Cell Tower Triangulation
Wifi Hotspot cataloging
Randomly assuming you are in Cupertino
There are tradeoffs based on speed, precision, and available hardware. A first Gen iPad will only have the 3 option available while the iPhone simulator makes use of the last mechanism.
You can observe the difference in these systems in the map application where it initially guesses based on the cell tower, then refines the guess via GPS.
Only options #3 requires a data connection.
And for the humor impaired including #4 was not totally serious although it is functionally correct. (I think they simulate the GPS reporting that location rather than just hard coding it, but I haven't checked.)
From How does CoreLocation locate the device?
The iPod Touch does something like this. It doesn't have a GPS chip, but instead uses the available WiFi networks in the area to get a rough idea of where you're located.
Is it possible to find the current location of an iphone as an address rather than as GPS coordinates using the API?
What you're looking for is MKReverseGeocoder.
What you could do is take the GPS coordinates and put them into Google maps to get the address. It seems that Google has an API that you can interact with, but I don't have any experience with it.
Good luck!
I want to build an iPhone App that should contact a server that is nearest to its location.
The app itself knows where the servers are located and it should find out which one to choose.
Because I expect many users with an iPod touch I can't use GPS to do this.
On StackOverflow and ServerFault I found this possible solutions:
Use Anycast technology to route users => I can't use this method because the device itself should route the requests and know where they are going.
Get country code and use the Google Directions API to determinate which server is nearest.
Get location by IP (GeoDNS etc.) and do the same (see above).
Method 2 seems good but I have three questions to that:
The API sends me the whole route from point x to point z. I just want to have distance. Is there a way to do that?
Google says they have a usage limit of 2,500 request per day. How do they control that? By IP? I ask this because they say you don't have to use an API key - how do they control then?
Is is a good idea to use Google without having any trouble later? My app itself will be free but I'll have In-App Purchases in it. Does that matter?
I hope somebody has experience in this. Thanks in advance!
Paul
In many cases, iOS will still return a location when requested on devices without GPS. Remember, the first generation iPhone didn't have GPS, but could still do location based services. iOS will use a number of techniques (IP geolocation, skyhook, etc) to find the location of a user, in addition to GPS.
Anyway, to answer some of your questions:
The 2,500 requests per day is per end user, or typically per IP address. So you shouldn't need to worry about getting capped. You should however be aware that you need to display a Google Map to use the API, so if you're using their API and not using a mapView you may have an issue.
I'm not entirely sure why you would need to use the Google directions API in the first place. If you can get lat/lon coordinates of both the user's current location and your servers you can just use iOS's built-in CoreLocation methods to get the distance between them, and decide accordingly ([CLLocation getDistanceFromLocation]).
I would like a map inside my iphone app which I want to query with search terms depending on certain values.
Does the mapkit framework accept queries of e.g. The United States and then display them?
I know this is really simple compared to the uses available from mapkit, that is why I wonder if it is covered?
This answer might be useful:
How do I do geocoding (NOT reverse geocoding) on iPhone?
Currently MapKit only provides Reverse Geocoding from coordinates to an address. For forward geocoding (an address or placename to coordinates) you'll need to use a geocoding API.
If your application only has a set number of things to be searched and you know the coordinates (like countries in your example) you could store and search them in core data, sqllite etc.
I am wondering if there is some way to find people that are near you using data supplied by the Core Location Framework. If you can get the other person's CLLocation's description attribute, I assume there must be some way to compare this in terms of location to your location.
Thanks for any help.
Core Location can only gather location data from the device it is running on, so it won't be able to get location information from other devices. Instead you want to implement some centralized server to handle the location data of all devices using an app, and let individual devices talk to the server for this information.