Methods and systems for directing movement of a tool in hair transplantation procedures

Methods and systems are provided useful in various procedures, including hair harvesting and implantation, and further including computer-implemented and/or robotic hair transplantation. Methodologies are provided which enable selection of follicular unit harvesting or implanting sites. In various cases, such selection may be made using a lowest and closest method, overlap-based methods, position-based methods, pattern-based methods, and/or a combination of these methods. In various combinations of the methods, the output selection from one of the methods may be used as an input for one of the other methods.