<?php 

$fields_spec = array(

  'cap' => array('numeric'),

  'org_lat' => array('numeric'),

  'org_lon' => array('numeric'),

  'dist' => array('numeric'),

  'title' => array(),

);

$validator = new FormValidator($fields_spec);

$is_valid = $validator->validate($_GET);

if ($is_valid) {

  $input = $validator->sane_values();

  if (isset($input['cap'], $input['org_lat'], $input['org_lon'])) {

    $cap = $input['cap'];

    $org_lat = $input['org_lat'];

    $org_lon = $input['org_lon'];

    $show_capline = true;

  } else {

    $show_capline = false;

  }

}

 ?>