在ArcGIS 10中Web Mercator有三种EPSG编号。他们分别是EPSG3857 、EPSG102100
EPSG102113。其实三者表示同一个投影，而这个投影跟谷歌以及Open Street Map等使用的投影EPSG:900913是一致的，只是这个编号以前人们使用的时候并没有被EPSG组织采纳。
以下是这几个编号代表的投影在ArcGIS中的元数据信息：（其中EPSG3857 EPSG102100 完全相同，EPSG102113稍有差异）
EPSG3857 - WGS_1984_Web_Mercator_Auxiliary_Sphere
EPSG102100 - WGS_1984_Web_Mercator_Auxiliary_Sphere
PROJCS[
"WGS_1984_Web_Mercator_Auxiliary_Sphere",
GEOGCS[
"GCS_WGS_1984",
DATUM["D_WGS_1984", SPHEROID["WGS_1984", 6378137.0, 298.257223563]],
PRIMEM["Greenwich", 0.0],
UNIT["Degree", 0.0174532925199433]
],
PROJECTION["Mercator_Auxiliary_Sphere"],
PARAMETER["False_Easting", 0.0],
PARAMETER["False_Northing", 0.0],
PARAMETER["Central_Meridian", 0.0],
PARAMETER["Standard_Parallel_1", 0.0],
PARAMETER["Auxiliary_Sphere_Type", 0.0],
UNIT["Meter", 1.0]
]
EPSG102113 WGS_1984_Web_Mercator
PROJCS[
"WGS_1984_Web_Mercator",
GEOGCS["GCS_WGS_1984_Major_Auxiliary_Sphere",
DATUM["D_WGS_1984_Major_Auxiliary_Sphere",SPHEROID["WGS_1984_Major_Auxiliary_Sphere",6378137.0,0.0]],
PRIMEM["Greenwich",0.0],
UNIT["Degree",0.0174532925199433]
],
PROJECTION["Mercator"],
PARAMETER["False_Easting",0.0],
PARAMETER["False_Northing",0.0],
PARAMETER["Central_Meridian",0.0],
PARAMETER["Standard_Parallel_1",0.0],
UNIT["Meter",1.0]
]