How to select points specified in geolocation at a certain radius in a telegram bot?

Question

PHP

There are set points in the telegram bot (during registration, the client indicates the address of the service), the user sends his location and selects the search radius, the bot must show the points corresponding to the specified radius.
I've searched everywhere, but I can't find the answer, can someone tell me? php language

Answer 1

Depending on the number of points. If you have few of them there, and there are no problems to calculate, then use the distance calculation function. For example, I have a function for POINT values, rewrite yourself under lat long.
And further through foreach you check necessary conditions.

static function distance($point1, $point2, $unit = 2 ) {
 
        if (!$point2) return null;
        if (!$point1) return null;

        $point1 = explode(',', $point1);
        $lon1 = $point1[0];
        $lat1 = $point1[1];

        $point2 = explode(',', $point2);
        $lon2 = $point2[0];
        $lat2 = $point2[1];

        if ($lon1 == 0 || $lon2 == 0) {
            return null;
        }

        $theta = $lon1 - $lon2;
        $dist = sin(deg2rad($lat1)) * sin(deg2rad($lat2)) +  cos(deg2rad($lat1)) * cos(deg2rad($lat2)) * cos(deg2rad($theta));
        $dist = acos($dist);
        $dist = rad2deg($dist); 
        $miles = $dist * 60 * 1.1515;

        switch ($unit) {
            case(self::UNIT_KM) :
                $out = $miles * 1.609344;
                break;
            case(self::UNIT_MI) :
                $out = $miles;
                break;
            case(self::UNIT_NA) :
                $out = $miles * 0.8684;
                break;
        }
        return $out;
    }

If you have through the base, then google gis functions for your base. there is even more elementary, up to the radius.
You can also roughly trim lat/lng to show the points you need, by simple subtraction. it will be rough, but sometimes this is enough for the task.