meta_query.php

<?php

$query = new WP_Query([
  'meta_query' => [
    'relation' => 'AND',
    [
      'key' => 'locationlat',
      'value' => [$sw[0], $ne[0]],
      'type' => 'numeric',
      'compare' => 'BETWEEN'
    ],
    [
      'key' => 'locationlng',
      'value' => [$sw[1], $ne[1]],
      'type' => 'numeric',
      'compare' => 'BETWEEN'
    ]
  ]
]);