1.18 Three-Dimensional Histogram

A three-dimensional histogram displays tabulated crosstabulations, percents, density, and so on as solid bars. Each bar represents a nonoverlapping interval of two quantitative variables. The resulting three-dimensional representation is projected onto a plane for display. The following steps create a three-dimensional histogram of a bivariate normal density function and display the results in Figure 1.96:

data normal;
   do x = -4 to 4 by 0.5;
      do y = -4 to 4 by 0.5;
         z = 0.164 * exp(-0.5 * ((x + y * 0.25) * x + (x * 0.25 + y) * y));
         output;
      end;
   end;
run;

proc template;
   define statgraph bihistogram1;
      begingraph;
         entrytitle "Bivariate Normal Density";
         layout overlay3d / cube=false;
            bihistogram3dparm x=x y=y z=z;
         endlayout;
      endgraph;
   end;
run;

proc sgrender data=normal template=bihistogram1;
run;