Abstract
In this paper, we presented the principles and the BASIC program for drawing three-dimensional contour map of grid data on the screen of the personal computer. This contouring program consists of two parts: (1) contouring of grid data (modified from subroutine *CONTR by Shiono et al., 1985) and (2) three-dimensional projection of contours (modified from program BLOCK by Shiono et al., 1984) .
