Ok, thank you for asking nonetheless!
We are analysing the Stanford EDFs from the STAGES dataset. The EDFs were recorded using the SOMNOmedics data collection system.
The body position (BPos) channel appears to take on 5 discrete values. Our best guess is: 117.7 (supine), 78.44 (left or right), 50.98 (left or right), 23.53 (upright), 0.004608 (prone).
Could someone please confirm whether this is correct or not?
Thank you, have a great day!