SECTION 15.15 DENSITY PLOTS
This routine provides a density plot of an X and a Y variable.
The MAIN program should include
COMMON/BPRINT/IPT,NFILE,NDIG,NPUNCH,JPT,MFILE
CALL DFLT
The call to the routine is
CALL DENSPLOT(X,N)
where
X is a REAL*4 array dimensioned X(N,2) and which contains in column 1 the X-variable and in column 2 the Y variable. N is the number of observations.
The range of X and Y values is divided into 60 equally spaced intervals and the number of observations with X and Y values falling in the various 3600 rectangles is counted. A plot is produced in which integers in a 60 by 60 grid represent the number of observations falling into each sub rectangle according to the following table:
Plotting symbol
Digit Number of points
0 0
1 1
2 2
3 3
4 4-5
5 6-7
6 8-13
7 14-20
8 21-28
9 >28