If your selected Shape Layer Type is Node Reach, shapes will be created using data in the Node Reach Radius field. Since this field contains only numerical values with no unit, Reach Radius Unit setting can be used to select which unit is used to determine the radius of each shape – kilometers or miles.

For example, if a data point contains ‘10’ in the Node Reach column, its surrounding circle will have a radius of 10 kilometers if your selected unit is km, or 10 miles if the selected unit is mi.