NAME: oplerr PURPOSE: Overplot data points with accompanying x or y error bars. CATEGORY: 2-D plotting CALLING SEQUENCE: OPLERR, [ X ,] Y , ERR [, DIR= ] [, PSYM= ] [, SYMSIZE= ] [, COLOR= ] INPUTS: Y = array of Y values. ERR = array of error bar values. OPTIONAL INPUT PARAMETERS: X = optional array of X values. The procedure checks whether or not the third parameter passed is a vector to decide if X was passed. If not passed, then INDGEN(Y) is assumed. DIR = direction to put error bar (default = 6) PSYM = plotting symbol (default = +7) SYMSIZE = symbol size (default = 1.0) COLOR = color for the symbols (default = !P.COLOR) COMMON BLOCKS: None. SIDE EFFECTS: None. RESTRICTIONS: Arrays must not be of type string. There must be enough points to plot. PROCEDURE: A plot of X versus Y with error bars drawn from the point in the direction specified by DIR. Recognized values for DIR are: 1 X + ERR 2 Y + ERR 3 X - ERR 4 Y - ERR 5 X - ERR and X + ERR 6 Y - ERR and Y + ERR (default) Plot is written to the output device over any plot already there. MODIFICATION HISTORY: William Thompson Applied Research Corporation July, 1986 8201 Corporate Drive Landover, MD 20785 Marc Buie Lowell Observatory 1991 October 11 Modified to allow specifying the direction for the error bars. Change PSYM to a keyword parameter 1992 June 24, Add SYMSIZE as a keyword parameter 94/09/14, MWB, added NOCLIP keyword parameter