Is it possible to hide fields on node edit form?
You can use the Field permissions module and disable the edit permission for that field, or you can use hook_form_alter and the #access property, here's an example:
/**
 * Implements hook_form_alter().
 */
function mymodule_form_alter(&amp;$form, $form_state, $form_id) {

  if ($form_id == &quot;contenttype_node_form&quot;) {
    $form['field_foo']['#access'] = FALSE;
  }
}

For a node edit form you must also check if the node exists.