Research Of Coordinate System’s Application In Coastal Areas Of Tangshan

1954 Beijing coordinate system was established in Tangshan coastal area,with the establishing of xi’an coordinate system and WGS-84 national geodetic coordinate system.Since the destruction of the control points in the Tangshan earthquake, Tangshan independent coordinate system was established based on 1954 Beijing coordinate system.However, due to different reference ellipsoid of different coordinate systems,there will be a loss of accuracy at the coordinate conversion between different coordinate benchmark.This paper analyzed coordinate transformation in Tangshan coastal area of nearly 2600 square kilometers.Different coordinate transformation models, characteristics and applicability were Introduced. Combined with the situation of Tangshan coastal area, the coordinate was transformed using four parameters and seven parameters between national 80 to Tangshan local coordinate system and the WGS- 84 to Tangshan local coordinate system.Using three sets of control point coordinates, the country’s 80 respectively to the same period to tangshan tangshan local coordinate system and WGS- 84 coordinate system to the seven and four parameters of coordinate transformation. In the distribution of point’s influence on the precision of coordinate transformation, using three, four and multiple control points within the scope of the different distribution of the surveyed area and ophiolites in duolie, transform and analy coordinate precision; in the situation of common point of gross error factors impact on the coordinate transformation,Gross error of the random 5 cm and 20 cm on the plane was introduced and then analys the result. Some conclusions and beneficial reference for specific engineering application was given.Tangshan coastal area coordinate conversion software was written by C# with complete functions. It has simple interface design, operation and reliable accuracy. The effectiveness of the above conclusion was validated by the software.