[~]$ xprop -root -notype _NET_DESKTOP_GEOMETRY
_NET_DESKTOP_GEOMETRY = 3840, 1200
[~]$ xprop -root -notype _NET_DESKTOP_VIEWPORT
_NET_DESKTOP_VIEWPORT = 0, 0
[~]$ xprop -root -notype _NET_NUMBER_OF_DESKTOPS
_NET_NUMBER_OF_DESKTOPS = 3
[~]$ xwininfo -root | grep geometry
  -geometry 3840x1200+0+0