the design development and evaluation of a differential pressure gauge directional wave monitor water waves pressure transducers kl b theory of analysis selecting the x y coordinate system in the horizontal with the origin at the instruments center as in figure iv 1 the dpg is assumed to faithfully record the water surface displacement quotncxyt at the center the slopes y at a and c and r y at b and d the curvatures rix yv across the center can be arithmetically approximated by ix rixcax and i1yb tyday respectively with the present dpg configur pfb192.jpg from i1yb View Photo