
Missing Values
If values of either of the plotting variables are missing, then PROC PLOT does not
include the observation in the plot. However, in a plot of Y*X, values of X with
corresponding missing values of Y are included in scaling the X axis, unless the
NOMISS option is specified in the PROC PLOT statement.
Hidden Observations
By default, PROC PLOT uses different plotting symbols (A, B, C, and so on) to
represent observations whose values coincide on a plot. However, if you specify your
own plotting symbol or if you use the OVERLAY option, then you might not be able to
recognize coinciding values.
If you specify a plotting symbol, then PROC ...