PRO ploterr, x, y, xerr, yerr, NOHAT=hat, HATLENGTH=hln, ERRTHICK=eth, $ ERRSTYLE=est, TYPE=itype, XRANGE = xrange, XTYPE=xtype, YTYPE=ytype, $ NSKIP = nskip, NOCLIP = noclip, ERRCOLOR = ecol, $ _EXTRA = pkey, ANONYMOUS_ = DUMMY_ ;+ ; NAME: ; PLOTERR ; PURPOSE: ; Plot data points with accompanying X or Y error bars. ; EXPLANATION: ; This is a greatly enhanced version of a standard IDL Library routine. ; ; CALLING SEQUENCE: ; ploterr, [ x,] y, [xerr], yerr [, TYPE =, /NOHAT, HATLENGTH= , ; ERRTHICK=, ERRSTYLE=, ERRCOLOR = ] ; ; INPUTS: ; X = array of abcissae. ; Y = array of Y values. ; XERR = array of error bar values (along X) ; YERR = array of error bar values (along Y) ; ; OPTIONAL INPUT KEYWORD PARAMETERS: ; TYPE = type of plot produced. The possible types are: ; TYPE = 0 : X Linear - Y Linear (default) ; TYPE = 1 : X Linear - Y Log ; TYPE = 2 : X Log - Y Linear ; TYPE = 3 : X Log - Y Log ; Actually, if 0 is specified, the XTYPE and YTYPE keywords ; are used. If these aren't specified, then a linear-linear ; plot is produced. This keyword is available to maintain ; compatibility with the previous version of PLOTERR. ; NOHAT = if specified and non-zero, the error bars are drawn ; without hats. ; HATLENGTH = the length of the hat lines used to cap the error bars. ; Defaults to !D.X_VSIZE / 100). ; ERRTHICK = the thickness of the error bar lines. Defaults to the ; THICK plotting keyword. ; ERRSTYLE = the line style to use when drawing the error bars. Uses ; the same codes as LINESTYLE. ; ERRCOLOR = scalar integer (0 - !D.N_TABLE) specifying the color to ; use for the error bars ; NSKIP = Integer specifying the error bars to be plotted. For example, ; if NSKIP = 2 then every other error bar is plotted; if NSKIP=3 ; then every third error bar is plotted. Default is to plot ; every error bar (NSKIP = 1) ; ; ; RESTRICTIONS: ; Arrays must not be of type string. There must be enough points to plot. ; If only three parameters are input, they will be taken as X, Y and ; YERR respectively. ; ; EXAMPLE: ; Suppose one has X and Y vectors with associated errors XERR and YERR ; ; (1) Plot Y vs. X with both X and Y errors and no lines connecting ; the points ; IDL> ploterr, x, y, xerr, yerr, psym=3 ; ; (2) Like (1) but plot only the Y errors bars and omits "hats" ; IDL> ploterr, x, y, yerr, psym=3, /NOHAT ; ; WARNING: ; This an enhanced version of a procedure that already exists in the ; standard IDL V4.0 distribution. Any call to the standard IDL version ; should also work with this version, but the reverse is not true. ; ; PROCEDURE: ; A plot of X versus Y with error bars drawn from Y - YERR to Y + YERR ; and optionally from X - XERR to X + XERR is written to the output device ; ; MODIFICATION HISTORY: ; William Thompson Applied Research Corporation July, 1986 ; DMS, April, 1989 Modified for Unix ; Michael R. Greason ST Systems ; May, 1991 Added most of the plotting keywords, put hats ; on the error bars. ; K. Venkatakrishna Added option to plot xerr, May, 1992 ; Michael R. Greason Corrected handling of reversed axes. Aug. 1992. ; W. Landsman Removed CHAN keyword for V4.0 compat. June 1995 ; W. Landsman Use _EXTRA keyword July 1995 ; W. Landsman Plot more than 32767 points Feb 1996 ; W. Landsman Fix Y scaling when only XRANGE supplied Nov 1996 ; W. Landsman Added NSKIP keyword Dec 1996 ; Converted to IDL V5.0 W. Landsman September 1997 ;- ; Check the parameters. On_error, 2 np = N_params() IF (np LT 2) THEN BEGIN print, "PLOTERR must be called with at least two parameters." print, "Syntax: ploterr, [x,] y, [xerr], yerr" RETURN ENDIF ; Error bar keywords (except for HATLENGTH; this ; one will be taken care of later, when it is ; time to deal with the error bar hats). IF (keyword_set(hat)) THEN hat = 0 ELSE hat = 1 if not keyword_set( THICK ) then thick = !P.THICK if (n_elements(eth) EQ 0) THEN eth = thick IF (n_elements(est) EQ 0) THEN est = 0 IF (n_elements(ecol) EQ 0) THEN ecol = !P.COLOR if N_elements( NOCLIP ) EQ 0 then noclip = 0 if not keyword_set(NSKIP) then nskip = 1 ; Other keywords. IF (keyword_set(itype)) THEN BEGIN CASE (itype) OF 1 : ytype = 1 ; X linear, Y log 2 : xtype = 1 ; X log, Y linear 3 : BEGIN ; X log, Y log xtype = 1 ytype = 1 END ELSE : ENDCASE ENDIF if not keyword_set(XTYPE) then xtype = 0 if not keyword_set(YTYPE) then ytype = 0 ; If no x array has been supplied, create one. Make ; sure the rest of the procedure can know which parameter ; is which. IF np EQ 2 THEN BEGIN ; Only Y and YERR passed. yerr = abs(y) yy = x xx = indgen(n_elements(yy)) xerr = make_array(size=size(xx)) ENDIF ELSE IF np EQ 3 THEN BEGIN ; X, Y, and YERR passed. yerr = abs(xerr) yy = y xx = x ENDIF ELSE BEGIN ; X, Y, XERR and YERR passed. yerr = abs(yerr) yy = y xerr = abs(xerr) xx = x ENDELSE ; Determine the number of points being plotted. This ; is the size of the smallest of the three arrays ; passed to the procedure. Truncate any overlong arrays. n = N_elements(xx) < N_elements(yy) IF np GT 2 then n = n < N_elements(yerr) IF np EQ 4 then n = n < N_elements(xerr) IF n LT 2 THEN $ message,'Not enough points to plot.' xx = xx[0:n-1] yy = yy[0:n-1] yerr = yerr[0:n-1] IF np EQ 4 then xerr = xerr[0:n-1] ; If no y-range was passed via keyword or system variable, force one ; large enough to display all the data and the entire error bars. ; If a reversed y-range was passed, switch ylo and yhi. ylo = yy - yerr yhi = yy + yerr if not keyword_set( YRANGE ) then yrange = !Y.RANGE IF yrange[0] EQ yrange[1] THEN BEGIN if keyword_set( XRANGE ) then begin good = where( (xx GT min(xrange)) and (xx LT max(xrange)) ) yrange = [min(ylo[good]),max(yhi[good])] endif else yrange = [min(ylo), max(yhi)] ENDIF ELSE IF yrange[0] GT yrange[1] THEN BEGIN ylo = yy + yerr yhi = yy - yerr ENDIF ; Similarly for x-range if not keyword_set( XRANGE ) then xrange = !X.RANGE if NP EQ 4 then begin xlo = xx - xerr xhi = xx + xerr IF xrange[0] EQ xrange[1] THEN xrange = [min(xlo), max(xhi)] IF xrange[0] GT xrange[1] THEN BEGIN xlo = xx + xerr xhi = xx - xerr ENDIF endif ; Plot the positions. plot, xx, yy, XRANGE = xrange, YRANGE = yrange, XTYPE = xtype, YTYPE = ytype, $ _EXTRA = pkey, NOCLIP = noclip ; Plot the error bars. Compute the hat length in device coordinates ; so that it remains fixed even when doing logarithmic plots. data_low = convert_coord(xx,ylo,/TO_DEVICE) data_hi = convert_coord(xx,yhi,/TO_DEVICE) if NP EQ 4 then begin x_low = convert_coord(xlo,yy,/TO_DEVICE) x_hi = convert_coord(xhi,yy,/TO_DEVICE) endif ycrange = !Y.CRANGE & xcrange = !X.CRANGE FOR i = 0L, (n-1), Nskip DO BEGIN plots, [xx[i],xx[i]], [ylo[i],yhi[i]], LINESTYLE=est,THICK=eth, $ NOCLIP = noclip, COLOR = ecol ; Plot X-error bars if np EQ 4 then plots, [xlo[i],xhi[i]],[yy[i],yy[i]],LINESTYLE=est, $ THICK=eth, COLOR = ecol, NOCLIP = noclip IF (hat NE 0) THEN BEGIN IF (N_elements(hln) EQ 0) THEN hln = !D.X_VSIZE/100. exx1 = data_low[0,i] - hln/2. exx2 = exx1 + hln plots, [exx1,exx2], [data_low[1,i],data_low[1,i]],COLOR=ecol, $ LINESTYLE=est,THICK=eth,/DEVICE, noclip = noclip plots, [exx1,exx2], [data_hi[1,i],data_hi[1,i]], COLOR = ecol,$ LINESTYLE=est,THICK=eth,/DEVICE, noclip = noclip ; Plot Y-error bars IF np EQ 4 THEN BEGIN IF (N_elements(hln) EQ 0) THEN hln = !D.Y_VSIZE/100. eyy1 = x_low[1,i] - hln/2. eyy2 = eyy1 + hln plots, [x_low[0,i],x_low[0,i]], [eyy1,eyy2],COLOR = ecol, $ LINESTYLE=est,THICK=eth,/DEVICE, NOCLIP = noclip plots, [x_hi[0,i],x_hi[0,i]], [eyy1,eyy2],COLOR = ecol, $ LINESTYLE=est,THICK=eth,/DEVICE, NOCLIP = noclip ENDIF ENDIF NOPLOT: ENDFOR ; RETURN END