Same projection, different extents

Discussion created by kwikstrom on Oct 9, 2013
Latest reply on Oct 9, 2013 by MKennedy-esristaff
I have two files both projected in Sphere_Miller_Cylindrical with a central meridian set at 100 and both have GCS_Sphere_ARC_INFO.  One comes from a PGDB and the other is a shapefile.  I believe their origins is somehow responsible for this slight misalignment.  Zoomed into the African southwest coast, the coincident boundaries are off by 1.5 inches, and on the Indian southwest coast they are off by 6.5 inches.  Elsewhere, such as the American west coast, they align perfectly.

My questions are:
Is there a way to align these troubled spots perfectly?  How?
How do I know which output is the correct one?  What is the evidence?
Basically, what is going wrong?

My guess is it has to do with their different origins (.mdb and .shp) and/or the slightly different extents.

I realize for a map of such a scale that this ever so slight misalignment is redundant, but I need to know what is happening.

Any help is appreciated.  Cheers!