WGS84 coordinate system, web Mercator, gcj02 coordinate system, bd09 coordinate system - brief introduction to common coordinate systems

1,WGS84 coordinate

        WGS84 Coordinate system ： The earth coordinate system （World Geodetic System）, The international coordinate system . The equipment contains GPS The longitude and latitude obtained by the chip or Beidou chip are generally WGS84 Geographic coordinate system , At present, Google Maps uses WGS84 Coordinate system （ Except in China ）.

WGS84 Web Mercator projection coordinate system ： Also known as web Mercator , It is now mainstream Web The coordinate system used by the map , Such as foreign Google Maps,OpenStreetMap,Bing Map,ArcGIS and Heremaps etc. , Baidu map in China 、 Gould map 、 Tencent maps and sky maps are also based on Web Mercator （ For domestic policy reasons , Domestic maps will have encryption requirements , There are generally two situations , One is in Web Based on Mercator, the national standard encrypted by the national standard 02 Coordinate system , Familiar scale “ Mars coordinate system ”; The other is in the national standard 02 Further encryption in the coordinate system , Such as Baidu map BD09 Coordinate system ）.

3,GCJ02 coordinate

        GCJ02 Coordinate system ：GCJ-02 It's from the State Bureau of Surveying and mapping of China （G Express Guojia Country ,C Express Cehui Mapping ,J Express Ju game ） The coordinate system of geographic information system . from WGS84 The encrypted coordinate system . Google China adopts GCJ02 Geographic coordinate system . Also known as ： Mars coordinate system .

GCJ02 Longitude and latitude projection coordinate system ： The coordinate values of this coordinate system are in longitude and latitude format , Unit degree . there GCJ02 Latitude and longitude projection , That is to say WGS84 Based on longitude and latitude , Conduct GCJ-02 Bias .

GCJ02 Web Mercator projection coordinate system ： The coordinate value of this coordinate system is Web Mercator format , The unit is rice. . there GCJ02 Web Mercator , That is, in the standard Web Based on Mercator , Conduct GCJ-02 Bias .

4,BD09 coordinate

BD09 Coordinate system ： Baidu coordinate system ,GCJ02 The encrypted coordinate system .

BD09 Longitude and latitude projection coordinate system ： The coordinate values of this coordinate system are in longitude and latitude format , Unit degree . It is based on the standard longitude and latitude GCJ-02 After bias , Plus Baidu's own bias algorithm , That is to say, the deviation is added twice on the basis of the standard longitude and latitude .

BD09 Web Mercator shadow coordinate system ： The coordinate value of this coordinate system is Web Mercator format , The unit is rice. . It's in the standard Web Based on Mercator GCJ-02 After bias , Plus Baidu's own bias algorithm , That is to say Web On the basis of Mercator, the bias is added twice .

Original post ：https://www.jianshu.com/p/0dc88983686b,http://www.rivermap.cn/docs/show-1829.html