Three-dimensional mapping of the Moon can be accomplished with an Earth-based radar interferometer. Elevation data and radar imagery obtained with this technique are presented for the Tycho Crater area, with a spatial resolution of 200 m and a height resolution of 30 m. The radar maps are displayed in standard cartographic projections with appropriate corrections for elevation-induced geometric distortions. The digital elevation model allows detailed morphometry of the 85 km diameter crater: the floor of Tycho lies 3970 m below a 1738 km radius sphere, and the crater's central peak rises 2400 m above the floor. The average rim crest elevation is 730 m above the 1738 km datum, giving a mean rim to floor depth of 4700 m. The floor has two distinct units with the western section being higher in elevation by ~200 m. This dichotomy is consistent with an asymmetry in the crater shape which reveals that maximum wall slumping occurred in the western and southwestern regions of the crater. Comparison of the radar-derived topography with 87 altimetry points from the Clementine lidar experiment shows rms deviations of ~90 m after a 0.11¿ latitude correction to the location of all the Clementine altimetry points. ¿ 1999 American Geophysical Union