Technical discussion: Issues related to setting out construction coordinates
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This post was last edited by hesonchang214 on 2015-9-2 at 09:33. The site design specifies two control points with GPS-derived geodetic coordinates, S1 and S2; the building is not aligned due north, with an angle of 4° between its true north direction and true north. The drawings provide the two geodetic coordinates of the building’s corners, A1 and A2. Is it possible to use a total station to locate these two points of the building directly using points S1 and S2? Could it be that the coordinates displayed are those of true north, resulting in an angular deviation from the north direction indicated on the drawing?
Do we still have to use GPS to locate points A1 and A2?
It can be released, but generally three control points are required, and they need to be reviewed regularly
It is recommended that you first have the design institute review it and produce official documents before proceeding with further discussions.
Two points can also be used to determine the location, but generally three reference points (which we call leveling points) are employed; they are often needed by supervisors and owners when verifying coordinates. Actually, once these two points are determined, a total station can be used to determine the coordinates of all buildings within the site.
If there are two control points with geographic coordinates S1 and S2, three reference points can be established; it is common for buildings not to be aligned due north. The deviation angle between the building’s north orientation and true geographic north is indicated on the diagram, with the drawing being made based on the building’s north orientation.