<?php
/**
 * GeometryCollection: A heterogenous collection of geometries  
 */
class GeometryCollection extends Collection 
{
  protected $geom_type = 'GeometryCollection';
  
  // We need to override asArray. Because geometryCollections are heterogeneous
  // we need to specify which type of geometries they contain. We need to do this
  // because, for example, there would be no way to tell the difference between a
  // MultiPoint or a LineString, since they share the same structure (collection
  // of points). So we need to call out the type explicitly. 
  public function asArray() {
    $array = array();
    foreach ($this->components as $component) {
      $array[] = array(
        'type' => $component->geometryType(),
        'components' => $component->asArray(),
      );
    }
    return $array;
  }
  
  // Not valid for this geomettry
  public function boundary() { return NULL; }
  public function isSimple() { return NULL; }
}