Easy axis aligning. Since the control points are all marked on the poles, it is easy to identify them in digitizing. It is easy to assemble, dissemble, and carry the poles. Flexible software supports. A theodolite should be used in measuring the angular positions of the poles and the control points.
Surveying is a big burden in the competition situations.
The distance between the adjacent points is constant. The horizontal angular positions of the poles are used in computing the X and Y coordinates of the control points while the vertical angular positions of the control points are used in computing the Z coordinates. Note that the origin of the coordinate system, at this point, is located right below the theodolite at the height of the first control point of the first pole and that the X-axis is aligned along the direction of the horizontal 0 . Now, the 3-D coordinates need to be expressed in the user's coordinate system. Missing points .