Objective C - OS GB Grid Ref to Lat Lon - ios

Does any one know of a way to convert from OSGB easting northing to a WGS84 Lat Lon?
I'm currently using the CBLocation library to convert from Lat Lon to OS but I now need to do this the other way round.
Thanks in advance.

I am told this document tells how
http://www.ordnancesurvey.co.uk/docs/support/guide-coordinate-systems-great-britain.pdf

Related

How can I convert the data from Polygon to lat, lng

image below is the data that I have and I do not know what is the type of coordinates! I thought it was UTM but it is not!
Can you please help me to understand the type and the way of converting it to the lat and lng?!

Obtaining UTM Zone, Easting and Northing using Core Location in iOS7 and greater

I am new to Objective-C, but have written a test app that shows me basic CLLocationManager info such as Heading, Course, Distance, Speed, Latitude and Longitude and the GPS data timeStamp info. What I need is the corresponding UTM coordinates for a given NAD83 and/or WGS84 projection including the UTM Zone letter and numeric designator (e.g. 16-T) wherer I live in northern Indiana. So, if I have :
LAT: 40.410250
LON: -86.127550
I need to convert or obtain through some (hopefully) existing method the UTM Zone, Easting and Northing coordinates of a given LAT/LON coordinate.
Any help is appreciated.
Thanks... Tim

convert eastings and northings to latitude and longitude on ios

I have a data set of eastings and northings and I need to convert these to a latitude and longitude value. Does anyone have any idea how to do this on iOS. I have tried using convert eastings and northings
javascript function but I got stuck in an infinite loop in the do while statement.
If anyone has any thoughts or experience on the matter please do share, I would really appreciate it.
Many thanks
Jules
You need a projection library, and proj4 is a dominant one. Here's a helpful description of using it with iOS: https://gis.stackexchange.com/questions/6658/how-to-integrate-proj4-into-an-ios-iphone-project
You'll need to know what the source coordinate system is, e.g. UTM, NAD, mercator, etc.

how to handle foursquare api's sensitivity with lat, lng

In foursquare api explore, it automatically picks the lat, lng for your location
https://api.foursquare.com/v2/venues/trending?ll=40.7,-74&oauth_token=[TOKEN]&v=20120325
and it return lot of results for the above url.
While using a third party service to get lat, lng for my ip address I get the coordinates as 40.7013,-73.7074, just little different from what foursquare got for me. Guess what, it returns no results when these co-ordinates are specified.
Any idea how to handle this?
Thanks,
Mandeep.
Look at the api: https://developer.foursquare.com/docs/venues/trending
You can specify a radius up to about 2000 meters. That's not really very large...

What is the best and most precise data type for storing latitude longitude in iphone xcode?

I am building a geolocation based app and i want to know which data type is best for storing lat/long i am using doubleValue but i think we can be more precise like 10 decimal places .
double is the value used by the iOS itself. iOS uses CLLocationDegrees to represent lat/long values which is a typedef of double.
IMO, using double/CLLocationDegrees would be the best choice.
Looking at the definition of CLLocationCoordinate2D:
typedef struct {
CLLocationDegrees latitude;
CLLocationDegrees longitude;
}
CLLocationCoordinate2D;
and then the location of CLLocationDegrees;
typedef double CLLocationDegrees;
we can see that the precision is given as double. Thus, you can't make it better than that.
There's already an answer to that in the iOS SDK :)
Take a look at CLLocationCoordinate2D - it's used by CoreLocation to store it's lat/lngs using the CLLocationDegrees type. If that's the accuracy CoreLocation gives you then that's a accuarate as it's going to get!
No it will not, because the lat/long iOS will use is also a double.
/*
* CLLocationDegrees
*
* Discussion:
* Type used to represent a latitude or longitude coordinate in degrees under the WGS 84 reference
* frame. The degree can be positive (North and East) or negative (South and West).
*/
typedef double CLLocationDegrees;

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