geolocation

I have a embedded database in my app that has all Latitude and Longitude of some interested points and I need to know my distance from these points(get my position using GPS). My problem is: I've just figured out that SQLite can't calculate distance using the query that I have because it doesn't calculate trigonometry functions(SIN, COS...). I was trying to avoid calculating these distances programatically using this query: NSLog(@"SELECT ((ACOS(SIN(%@ * PI() / 180) * SIN(lat * PI() / 180) + COS(%@ * PI() / 180) * COS(lat * PI() / 180) * COS((%@ – lon) * PI() / 180)) * 180 / PI()) * 60 * 1

My app runs a geolocalisation service that the user can active or disactive by a toggleButton. To check the status of the service, I write a boolean in the Shared Preferences. I listen the beginning of the service and the end of it thanks to the onDestroy() of my service. My problem is that: When the user kill the service with the "advanced task killer", I can't know that the service is killed, the onDestroy is not called ! How can I deal with that? Thanks for your help. Florent When a process is killed (using ATK or android's own force stop button, or the function here ), it is immediately

What algorithm/formula can I use to calculate a LatLng point 5 meters closer to another LatLng point? I'm trying to write a function with 2 LatLng parameters and have it return a LatLng that is 5 meters from the first LatLng and in the direction of the second LatLng. Have a look at Android Map Utils library, specifically the SphericalUtil class. 1.) Call the method computeHeading to obtain your heading from first to second 2.) Call the method computeOffset to solve for the location 5 meters from your first point Hope this helps 来源： https://stackoverflow.com/questions/26594445/move-a-latlng-5

Looking for a way to get a list of telephone area codes for a given latitude and longitude (and if necessary a given intl. code.) Note, I'm not talking about international dialing prefixes but the area codes within them. For example, Denver Colorado is covered by the area codes 303 and 720. It's at 39.739 -104.985 and is in NANP 1. So given 39.739,-104.985,1 I'd like to get back [303,720]. Libraries, web services, DB's, or raw data that needs to be parsed into a DB, e.g., a web page of shape points, are all fine and the more global coverage the better, but just NANP 1 would be a great help.

I am new to the whole 'spatial index' thing, but it seems to be the best solution for filtering based on latitude/longitude. So I added a column to my table: So I created a geometry field: ALTER TABLE `addresses` ADD `point` POINT NOT NULL And then I tried to add an index: ALTER TABLE `addresses` ADD SPATIAL INDEX ( `point` ) But I get an error: #1416 - Cannot get geometry object from data you send to the GEOMETRY field What am I doing wrong here? jisaacstone OK I found the solution: Can't create a spatial index if some of the column fields contain no data. After running UPDATE `addresses` SET