Presented on Tuesday, January 7, 2003 . We construct a detailed longitude-velocity diagram through the actual midplane of the Galactic H I disk. The Galactic midplane definition is based on single-dish sky surveys, and the detailed l-v slice ( Fig. 1 ) is extracted from the Canadian Galactic Plane Survey ( CGPS ; Taylor et al. 2003 ). ... Note: other slices offset from this one were not shown in the AAS poster for lack of space, but they are available here . ...