Basic check to use map marker location only once

<?php
/** basic check to keep only one map marker per location
 ** assumes lat is unique without having to check lng also
 **/

Class FWPMapDulicateChecker
{
    public $locations = [];

    function __construct() {

        add_filter( 'facetwp_map_marker_args', function( $args, $post_id ) {
            $lat = $args['position']['lat'];
            if ( false === array_search( $lat, $this->locations ) ) {
                $this->locations[] = $lat;
            } else {
                return false;
            }
            return $args;
        }, 10, 2 );
    }
}
new FWPMapDulicateChecker();