Imagine I have an Inkscape file (https://www.evernote.com/shard/s35/sh/13548dcc-2b50-4b9c-b383-e8c22536b397/2e51c7acc1d33630008dc28504232761) with the following rectangle:

I want to calculate the Y coordinate reported by Inkscape (596.654).
How can I do it?
I tried this:
1. The top of the page seems to have a Y coordinate of 744.
1. I subtract from that number the y coordinate of the rectangle in the XML editor (417) and its height (37) and get 744 - 417 - 37 = 290.
Note that the rectangle doesn't have any transforms and doesn't belong to a group.
Thanks in advance
Dmitri Pisarenko