Abstract: A process whereby a sequence of geometric transformations is applied to a three-dimensional data set so that the resulting stereogram has one image plane made congruent with one plane in the viewer's space. The image plane is usually, but not necessarily, the X-Z or ground plane of the image made congruent with some X-Z plane in the viewer's spatial environment, typically a desk top, table top or floor. When viewed from an angle of view and angle of regard which duplicates that used to create the stereogram, the resulting stereoscopic image appears as a virtual, erect, orthoscopic stereo environment whose X-Y-Z coordinates are congruent with the X-Y-Z coordinates of the viewer's space.