code: @Pure
  	public String getInternalId() {
  		final int endIndex = this.id.indexOf('#');
  		if (endIndex <= 0) {
  			return null;
  		}
  		return this.id.substring(0, endIndex);
  	}
docs: Extract the unique identifier stored in this geoId.
  
  @return the internal identifier or <code>null</code> if this
  geoid has invalid format.