Obtain approach radius from a geographical coordinate

Question

I have a PHP application that gets the latitude and longitude of an address, using the Google Maps API. The idea is to delimit a "tolerance" distance around this point to later validate whether the user is within the bounded radius.

From this one point I have, how can I get the coordinates of a radius of x meters around this point?

If there is no way to do this, how can I set a tolerance distance that the user may be from the set point?

OBS.: I don’t need to display lightning on the front end of the map (as shown here: How do I light a map with a proximation circumference?), but rather a way to, for example, calculate whether an A coordinate is within an x-metre radius of coordinate B.

Answer 1

You will solve this using this library to the Laravel, she works with spatial data types on Mysql. This library has several methods for working with coordinates, polygons, distance and etc.

After following the documentation for installation and configuration of the same, you will have more or less this:

Migration of your address table or table that will own the lat and lng:

Schema::create('addresses', function (Blueprint $table) {
    $table->increments('id');
    $table->string('zipcode');
    $table->integer('neighborhood');
    $table->string('street');
    $table->string('number');
    $table->string('complement');
    $table->string('landmark');
    $table->point('location'); // Lat e Long
    $table->tinyInteger('status')->default(1)->comment('0=Disabled, 1=Enabled');
    $table->timestamps();
});

Model:

use Grimzy\LaravelMysqlSpatial\Eloquent\SpatialTrait;

class Mall extends Model
{
    use SpatialTrait;

    protected $fillable = ['zipcode', 'neighborhood', 'street', 'number', 'complement', 'landmark', 'location', status];
}

Controller:

use App\Address; // Namespace do seu model
use Grimzy\LaravelMysqlSpatial\Types\Point;

class BikerQueueController extends Controller
{

    public function calcRadius( Request $request )
    {
        $lat = $request->input( 'lat' );
        $lng = $request->input( 'lng' );

        // O método distanceSphere() é da lib instalada, 
        // você deve informar 3 parâmetros: distanceSphere($geometryColumn, $geometry, $distance); A distância deve ser informada em milhas.
        $address = Address::distanceSphere( 'location', new Point( $lat, $lng ), 5000 )
                    ->whereStatus( 1 ) // Aqui é um exemplo de que você pode usar os métodos padrões do seu model junto com os métodos da lib
                    ->first();

        return (bool)$address; // retorna true ou false
    }
}

P.S: Please abstract the variables handling of the request and return method, the focus was only to show how you can do to know if a coordinate is within the radius of an address.