Project vs. Calculate Geometry

Discussion created by shaunoneil on Mar 27, 2013
Latest reply on Mar 28, 2013 by MKennedy-esristaff

I'm hoping somebody will be able to explain what's going on here.

I have a point with an x/y coordinate of 1,259,717 / 263,551 in State Plane, NAD83, Zone 4601 (Washington North).  If I use the project tool to project the point to NAD27 the point moves to 1,616,595 / 263,609 which I've confirmed with Corpscon.  However, if I instead, just change the coordinate system of the data frame to NAD27 and then calculate the geometry in the attribute table selecting the coordinate system of the data frame I get 1,619,290 / 263,551 - off by ~300'!  Any explanation for why this difference occurs?  Thanks. 

Shaun O'Neil
King County WTD