HMI context data:

The arrow in the box indicates the 'slit direction', the arrow outside the box the scanning direction.

 

Blue (red) color of the box indicates that the GRIS scan is flipped in the scanning direction with respect to HMI (or not).

Please note that the coordinates ('x/y-pos') given in the GRIS preview images are those from the fits headers, so they are not necessarily correct.