Illustration of the selection process for tidal tails and streams for one galaxy. Black annotations indicate that the unique identifier has not been attributed yet, while each color corresponds to one unique identifier. The linestyles correspond to the different users. The red arrows indicate which annotations are currently compared. a) Initialization: all the annotations of tidal tails and streams are considered. b) First iteration: the annotations of User 2 and User 1 are compared. c) Second iteration: comparison of the annotations of User 3 and User 2. d) Third iteration: comparison of the annotations of User 3 and User 1. e) Final step: for the annotations sharing the same unique identifier, only the one with the largest area is kept.