A conversion to Swift, taken from this answer: func locationWithBearing(bearingRadians:Double, distanceMeters:Double, origin:CLLocationCoordinate2D) -> CLLocationCoordinate2D { let distRadians = distanceMeters / (6372797.6) // earth radius in meters let lat1 = origin.latitude * M_PI / 180 let lon1 = origin.longitude * M_PI / 180 let lat2 = asin(sin(lat1) * cos(distRadians) + cos(lat1) * sin(distRadians) * cos(bearingRadians)) let … Read more
Here is the query I use on the store locator I work with: SELECT `id`, ( 6371 * acos( cos( radians( :lat ) ) * cos( radians( `lat` ) ) * cos( radians( `long` ) – radians( :long ) ) + sin(radians(:lat)) * sin(radians(`lat`)) ) ) `distance` FROM `location` HAVING `distance` < :distance ORDER BY … Read more
You can use the Google Geocoder service in the Google Maps API to convert from your location name to a latitude and longitude. So you need some code like: var geocoder = new google.maps.Geocoder(); var address = document.getElementById(“address”).value; geocoder.geocode( { ‘address’: address}, function(results, status) { if (status == google.maps.GeocoderStatus.OK) { // do something with the … Read more
Either of these work google.maps.event.addListener(marker, ‘click’, function (event) { document.getElementById(“latbox”).value = event.latLng.lat(); document.getElementById(“lngbox”).value = event.latLng.lng(); }); google.maps.event.addListener(marker, ‘click’, function (event) { document.getElementById(“latbox”).value = this.getPosition().lat(); document.getElementById(“lngbox”).value = this.getPosition().lng(); }); You might also consider using the dragend event also google.maps.event.addListener(marker, ‘dragend’, function (event) { document.getElementById(“latbox”).value = this.getPosition().lat(); document.getElementById(“lngbox”).value = this.getPosition().lng(); });
Well first of all if you have a lot of geospatial data, you should be using mysql’s geospatial extensions rather than calculations like this. You can then create spatial indexes that would speed up many queries and you don’t have to write long drawn out queries like the one above. Using a comparision with ST_Distance … Read more
If your code runs in a browser, you can use the HTML5 geolocation API: window.navigator.geolocation.getCurrentPosition(function(pos) { console.log(pos); var lat = pos.coords.latitude; var lon = pos.coords.longitude; }) Once you know the current position and the position of your “target”, you can calculate the distance between them in the way documented in this question: Calculate distance between … Read more
It seems you are measuring distance (R) in meters, and bearing (theta) counterclockwise from due east. And for your purposes (hundereds of meters), plane geometry should be accurate enough. In that case, dx = R*cos(theta) ; theta measured counterclockwise from due east dy = R*sin(theta) ; dx, dy same units as R If theta is … Read more
The big issue with plotting maps is that the spherical surface of the Earth cannot be conveniently converted into a flat representation. There are a bunch of different projections that attempt to resolve this. Mercator is one of the simplest: it assumes that lines of equal latitude are parallel horizontals, while lines of equal longitude … Read more
Wikipedia gives a pretty thorough discussion of the algebra here: http://en.wikipedia.org/wiki/Trilateration The first step, not really covered in the Wikipedia entry, is to convert your lat/long coordinates to Cartesian coordinates: x0 = cos( lon0 ) * cos( lat0 ) , y0 = sin( lon0 ) * cos( lat0 ) , z0 = sin( lat0 ) … Read more
For latitudes use: Decimal(8,6), and longitudes use: Decimal(9,6) If you’re not used to precision and scale parameters, here’s a format string visual: Latitude and Longitude ##.###### and ###.###### To 6 decimal places should get you to around ~10cm of accuracy on a coordinate.