You could specify a point by tapping or dragging on the screen.
You could also enter a polar coordinates or relative coordinates in keypad to specify a point.
Adjust a point
After specifying a point, you could adjust its position by the following ways:
（1）Tap on point marker and then dragging it to adjust its position;
（2）Change its polar coordinates or relative coordinates in keypad;
（3）Tap on coordinate marker(the rectangle box with X and Y) and change its absolute coordinates in keypad.
Confirm a point
After specifying a point or adjusting it, you could confirm its position by the following ways:
（1）Tap blank in drawing area;
（2）Tap “√” in keypad;
（3）Tap “√” keywords behind command prompts.
