3 implies an orthogonal, but unequally-spaced mapping. XINP C is assumed to lie in the range from 1 to M, YINP in the range from C 1 to N, where M and N are the dimensions of the grid. 4 implies a generalized distortion. XINP is assumed to lie C in the range from 1 to M, YINP in the range from 1 to N, where M C and N are the dimensions of the grid. C C Declare common blocks.
C C Do the mapping.
IF C C Done. If any area identifier is negative, turn off drawing. If drawing is turned on, draw the polyline. C C Done. C C Turn off shading.