old_contents: from django import template
  from django.utils.encoding import force_unicode
  
  register = template.Library()
  
  @register.filter
  def can_edit_geodata(user, geodata):
      if user.is_authenticated():
          if geodata.creator == user:
              return True
          else:
              return False
      else:
          return False
  
new_contents: from django import template
  from django.utils.encoding import force_unicode
  
  register = template.Library()
  
  @register.filter
  def can_edit_geodata(user, geodata):
      if user.is_authenticated():
          return (geodata.creator == user or user.is_staff)
      else:
          return False
  
subject: allow edition/deletion of geodata if user is staff