converting from 84 and plane rectangular coordinates to 80 coordinates system,this paper proposes a conversion algorithm of WGS84 geodetic coordinates-spatial Rectangular Coordinates-WGS80 geodetic coordinates to achieve the display of GPS positioning in the electronic map.

Using the results of the common points to directly determine the difference between the two ellipsoids so as to acquire geodetic coordinate of 80 coordinate, the author calculates Gauss plane coordinate by applying the two methods, with the accuracy to meet the .

The simple formula to compute geodetic coordinate from rectangular space coordinate;

Deducing from geodetic coordinate differential formula;

Road curve geodetic coordinate calculation based on branch traverse survey

The analysis of conversion from geocentric to geodetic coordinates with Newton iteration to solve non-linear equations

The mathematic characteristics of transition curve and its parallels, and geodetic coordinates calculating methods of the curve inflexions and points of intersection are analyzed,and the second development of the Auto CAD is used for the Visual LISP programs for the solution of the rigidity of the theory and the practicality of the calculation.

For the complex traditional arithmetic that is difficult to be applied to practice, this paper presents arithmetic of the coordinates transformation from geodetic coordinates to plane rectangular coordinates and screen coordinates.