WGS-84经纬度转百度平面坐标的离线转换方法研究

随着互联网的发展,以百度地图为代表的互联网地图被广泛应用到地理信息管理系统中。为了将以外业GPS测量为主的矢量数据应用到这类系统中,需要进行由WGS-84经纬度到百度平面坐标的转换。目前,借助百度官方提供的坐标转换API可以实现这种形式的坐标在线转换,然而这些矢量数据往往是以地图服务的形式发布在内网环境中,无法实现在线转换,故亟待引入一种离线转换算法。本文正是基于这种需求,提出了一种依托控制点库的WGS-84经纬度向百度平面坐标的离线转换方法,并对这种方法进行了精度评价。结果表明,该算法的转换精度可达米级,误差的主要来源为建立控制点库时在线调用百度坐标转换API产生的误差。

The Study of Off-line Coordinate Transformation Method for WGS-84 Longitude and Latitude to Baidu Plane Coordinate

With the development of the Intemet,Baidu map as the representative of the Intemet maps is widely used in geo-information management systems.In order to apply the vector data which obtain from field survey of GPS to these systems,it is necessary to transform WGS-84 longitude and latitude to Baidu plane coordinate.At present,this kind of coordinate transformation just can be realized in the form of on-line through the coordinate transform API provided by Baidu official.However,these vector data which usually be used in the local area network as map services cannot realize the on-line transformation.Therefore,an off-line transformation algorithm needs to be introduced immediately.Based on this demand,this paper puts forward a method to transform the WGS-84 longitude and latitude based on control point library to Baidu plane coordinate off-line,and carry out an accuracy evaluation of the method.The results showthat the transformation accuracy of the proposed algorithm can be up to a meter level,and the main source of error is the error generated whencalling the on-line Baidu API tobuild the control point library.