Equal Area projection to Web Mercator and back again - any impacts on area estimates?

[SharonWaltman]

I am searching for some ESRI papers that describe what happens when data sources that have an equal area projection (e.g. USA_Contiguous_Albers_Equal_Area_Conic_USGS_version) are transformed/projected to the Web Mercator system  and back again via Geometry Services (could be during an overlay with a separate data source, etc.).

Some of us neophytes are trying to wrap our brains around what impact this may or may not have on our area estimates. 

If you can point me to some references I would be very happy.  I am checking out ArcGIS Online Geometry Services presently. 

Thanks.

[MelitaKennedy]

There should be no effect.

Both projections are well-defined, and I consider them 'lossless'. Yes, there could be some very small movements in the coords, but well below data accuracy (like 5-6th or more decimal place).

It's possible you might lose data between them. Mercator is chopped off near the poles, so if you had data there, it would get clipped out.

Yes, web Mercator uses a sphere, but it's all being handled internally, and when data is unprojected back to lat/lon you get the original lat/lon values.

Melita