西安1980坐标转换为WGS1984坐标的3参数近似估算方法

在第一次全国水利普查的土壤侵蚀调查过程中,野外填图用到的地形图、遥感影像和GPS定位设备的大地坐标系不同,为野外调查工作带来了不便。为方便调查,需要将西安1980坐标转换为WGS1984坐标。利用coord软件和ESRI公司的Arcmap软件,在全国选取10个省(自治区)14个片区的61个样点,估算各片区西安1980坐标转换为WGS1984坐标的3参数,并分析利用分区3参数和全国统一3参数进行坐标转换后的精度。结果表明:采用分区3参数进行坐标转换时,平均经向和纬向误差均小于10 m,采用全国统一3参数进行坐标转换时,平均经向和纬向误差均小于15 m,无论采用分区3参数还是全国统一3参数进行坐标转换,均符合本次土壤侵蚀调查的精度要求,并可为国家或地区的其他类似调查提供方便。

Estimation of three parameters for transforming coordinate system from Xi' an-1980 into WGS-1984

Field work should be mapped for soil erosion survey in the first water conservancy survey of China,but the coordinate systems used for field support maps,remote imagery and GPS were different.So it has to be transformed from Xi’an 1980 into WGS-1984 in order to facilitate the investigation.In this study,61 sites were chosen for 14 parts in 10 provinces.Three parameters for transforming coordinate system from Xi’an-1980 into WGS-1984 were estimated by using coord software for every part and then averaged for both regional and national scales.Under the support of ArcMap software,61 sites in Xi’an-1980 coordinate system were transformed into WGS-1984,and their geographic errors were estimated by comparing the transformed WGS-1984 and google earth image coordinate system.The results showed that both longitudinal and latitudinal errors in average were less than 10 m using regional three parameters,and less than 15 m using national three parameters,which could satisfy the precision of 20 m for national soil erosion survey and could provide convenience for other similar surveys of the country or regions.