You can use this button to draw a new polygon with the stylus over a given map. Once drawn you can change the properties as name, color, pattern and shape type (Line/Area). If you want to modify with the stylus a given polygon, first be sure that is the "active" object and then press this button to add new points to the object.
Similary, you can use the button to draw with the stylus a new rectangle (paralell to North/East axis).
The button will allow you to draw a circle with the stylus. Press in the center and move it until the desired radius. The area will be updated during the creation.
Finally, with the use of this button you can create a circle from the data of GPS. Press the button in the center of circle and walk until the border. This last function is very suitable for draw the shapes of the "center pivot irrigation ", as you can see in the following image (Lubbock County, Texas)