code: public static int getIndicator(GeometryEnvelope envelope) {
  		int indicator = 1;
  		if (envelope.hasZ()) {
  			indicator++;
  		}
  		if (envelope.hasM()) {
  			indicator += 2;
  		}
  		return indicator;
  	}
docs: Get the envelope flag indicator
  
  1 for xy, 2 for xyz, 3 for xym, 4 for xyzm (null would be 0)
  
  @param envelope
  geometry envelope
  
  @return indicator