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ToBeReviewed/PLOTS/LABEL/

label_date.pro

topLABEL_DATE

result = LABEL_DATE(axis, index, x, DATE_FORMAT=DATE_FORMAT, MONTHS=MONTHS, OFFSET=OFFSET, _EXTRA=_EXTRA)

NAME: LABEL_DATE PURPOSE: This function labels axes with dates and times. CATEGORY: Plotting. CALLING SEQUENCE: To set up: dummy = LABEL_DATE(DATE_FORMAT='string') To use: PLOT, x, y, XTICKFORMAT='LABEL_DATE' INPUTS: No explicit user defined inputs. When called from the plotting routines, the input parameters are (Axis, Index, Value) KEYWORD PARAMETERS: DATE_FORMAT: a format string which may contain the following: %M for month (3 character abbr) %N for month (2 digit abbr) %D for day of month, %Y for 4 digit year. %Z for last two digits of year. For time: %H for Hours, 2 digits. %I for mInutes, 2 digits. %S for Seconds, 2 digits. %% is %. Other characters are passed directly thru. For example, '%M %D, %Y' prints DEC 11, 1993 '%M %2Y' yields DEC 93 '%D-%M' yields 11-DEC '%D/%N/%Y' yields 11/12/1993 '%M!C%Y' yields DEC on the top line, 1993 on the bottom (!C is the new line graphic command). MONTHS: The names of the months, a twelve element string array. If omitted, use Jan, Feb, ..., Dec. OFFSET: An optional starting offset of the plot. Unfortunately, single precision floating point is not accurate enough to properly represent Julian times. This offset, which may be double precision, contains an offset that is added to all x values, before conversion to Julian date and time. OUTPUTS: The date string to be plotted. COMMON BLOCKS: LABEL_DATE_COM. RESTRICTIONS: Only one date axis may be simultaneously active. PROCEDURE: Straightforward. For an alternative way to label a plot axis with dates, refer to the C() format code accepted within format strings (applicable via the [XYZ]TICKFORMAT keywords). This new format code was introduced in IDL 5.2. EXAMPLE: For example, to plot from Jan 1, 1993, to July 12, 1994: Start_date = julday(1, 1, 1993) End_date = julday(7, 12, 1994) Dummy = LABEL_DATE(DATE_FORMAT='%N/%D') ;Simple mm/dd x = findgen(end_date+1 - start_date) + start_date ;Time axis PLOT, x, sqrt(x), XTICKFORMAT = 'LABEL_DATE', XSTYLE=1 (Plot with X axis style set to exact.) Example with times: For example, to plot from 3PM, Jan 1, 1993, to 5AM, Jan 3, 1993: Start_date = Julday(1,1,1993) ;Also starting offset Start_time = (3+12)/24. ;Starting_time less offset End_time = (Julday(1,3,1993) - Start_date) + 5./24. ;Ending ;date/time - offset, note that the order of operations is ; important to avoid loss of precision. Dummy = LABEL_DATE(DATE_FORMAT='%D %M!C%H:%I', $ offset=Start_date) ;MMM NN HH:MM format x = findgen(20) * (End_time - Start_time) / 19 + start_time ;Time axis PLOT, x, sqrt(x), XTICKFORMAT = 'LABEL_DATE', XSTYLE=1 MODIFICATION HISTORY: DMS, RSI. April, 1993. Written. DMS, RSI. March, 1997. Added Time format.

Parameters

axis       

index       

x       

Keywords

DATE_FORMAT       

MONTHS       

OFFSET       

_EXTRA       

Other attributes

Common blocks used

label_date_com
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