Alignment Issue when using BaseMap

[RonanCrowley]

Hi,

I'm having issues using the ESRI JavaScript API aligning my data above it.

My data aligns perfectly with the ERSI MapServer Imagery (See attachment Align_1.png)


However, when I activate the TileBaseMapServiceLayer the data becomes misaligned (See attachment Align_2.png)


I'm trying to investigate why this is happening.

The BaseLayer is in spatial reference 102100 and the MapServer is in spatial reference 3857, but according to the documentation these are both identical.

3857     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]]


102100     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]]

Thanks,
Ronan