search for: xypts

Hello, dear R-users. I have 2-d dotplot with two variables: x, y. Dots on this dotplot are grouped in human-recogniseable areas. These areas are not round-shaped nor oval-shaped. They are free-form, but still recogniseable by an operator. What is ability in R to graphically (per mouse) define some area and to select all the cases felt in it? 'identify' is OK for 5-10 cases, but what