;------------------------------------------------------------- ;+ ; NAME: ; JD2MDAYS ; PURPOSE: ; Convert a range of Julian Days to month start and end JDs. ; CATEGORY: ; CALLING SEQUENCE: ; jd2mdays, jd1, jd2, mjds, mjde ; INPUTS: ; jd1, jd2 = first and last Julian day of a time range. in ; KEYWORD PARAMETERS: ; Keywords: ; APPROX_MAJOR=amaj Approximate number of days between ; major tick marks. Used to derive actual # days. ; MAJOR_V=majv Array of labeled tick mark values in ; Julian Days. ; MINOR_V=majv Array of minor tick mark values in ; Julian Days. ; FORMAT=frm Returned suggested format for time labels. ; OUTPUTS: ; mjds = array of Julian days for the first of each out ; month covered by the range. ; mjde = array of Julian days for the end of each out ; month covered by the range. ; COMMON BLOCKS: ; NOTES: ; Notes: intended for time axes involving month labels. ; Ex: if jd1 is for 29-Jan-1992 and jd2 is for 13-Jun-1993 ; then mjds and mjde each have 18 elements giving the ; Julian day numbers for the start and end of each of the ; 18 months from Jan 1992 to Jun 1993 inclusive. ; MODIFICATION HISTORY: ; R. Sterner, 29 Apr, 1993 ; R. Sterner, 1994 Mar 30 --- Extended time range upward. ; R. Sterner, 2012 Feb 13 --- Converted arrays from () to []. ; ; Copyright (C) 1993, Johns Hopkins University/Applied Physics Laboratory ; This software may be used, copied, or redistributed as long as it is not ; sold and this copyright notice is reproduced on each copy made. This ; routine is provided as is without any express or implied warranties ; whatsoever. Other limitations apply as described in the file disclaimer.txt. ;- ;------------------------------------------------------------- pro jd2mdays, jd1, jd2, mjds, mjde, approx_maj=amaj, $ major_v=majv, minor_v=minv, format=frm, help=hlp if (n_params(0) lt 2) or keyword_set(hlp) then begin print,' Convert a range of Julian Days to month start and end JDs.' print,' jd2mdays, jd1, jd2, mjds, mjde' print,' jd1, jd2 = first and last Julian day of a time range. in' print,' mjds = array of Julian days for the first of each out' print,' month covered by the range.' print,' mjde = array of Julian days for the end of each out' print,' month covered by the range.' print,' Keywords:' print,' APPROX_MAJOR=amaj Approximate number of days between' print,' major tick marks. Used to derive actual # days.' print,' MAJOR_V=majv Array of labeled tick mark values in' print,' Julian Days.' print,' MINOR_V=majv Array of minor tick mark values in' print,' Julian Days.' print,' FORMAT=frm Returned suggested format for time labels.' print,' Notes: intended for time axes involving month labels.' print,' Ex: if jd1 is for 29-Jan-1992 and jd2 is for 13-Jun-1993' print,' then mjds and mjde each have 18 elements giving the' print,' Julian day numbers for the start and end of each of the' print,' 18 months from Jan 1992 to Jun 1993 inclusive.' return endif ;-------- Initialize ------------ jd2ymd, jd1, y, m, d ; Convert 1st JD to yr, mnth, day. mjds = [ymd2jd(y,m,1)] ; 1st value in month start array. mjde = [ymd2jd(y,m,monthdays(y,m))] ; 1st value in month end array. ;-------- Loop through time range ---------- loop: m = m + 1 ; Next month. if m gt 12 then begin ; Next year. y = y + 1 m = 1 endif jd = ymd2jd(y,m,1) ; Next first of month. if jd gt jd2 then goto, next ; Got all values. mjds = [mjds,jd] ; Add new start to list. mjde = [mjde,ymd2jd(y,m,monthdays(y,m))] ; Add new end to list. goto, loop ;------- Find major and minor tick marks -------- next: if n_elements(amaj) eq 0 then return if amaj lt 1. then amaj = 1. ;------- Filter down through tick spacing values --------- ;------- Boundaries are geometric means between spacings ----- dx = 720 ; Major tick spacing. Values are in days. dx2 = 360 ; Minor tick spacing. frm = 'y$' if amaj lt 1800 then begin dx=360 & dx2=180 & frm = 'n$ y$' & end if amaj lt 255 then begin dx=180 & dx2=90 & frm = 'n$ y$' & end if amaj lt 147 then begin dx=120 & dx2=60 & frm = 'n$ y$' & end if amaj lt 104 then begin dx=90 & dx2=30 & frm = 'n$ y$' & end if amaj lt 73.48 then begin dx=60 & dx2=30 & frm = 'n$ y$' & end if amaj lt 42.43 then begin dx=30 & dx2=10 & frm = 'd$ n$ y$' & end if amaj lt 21.21 then begin dx=15 & dx2=5 & frm = 'd$ n$ y$' & end if amaj lt 12.25 then begin dx=10 & dx2=5 & frm = 'd$ n$ y$' & end if amaj lt 7.07 then begin dx=5 & dx2=1 & frm = 'd$ n$ y$' & end if amaj lt 3.16 then begin dx=2 & dx2=1 & frm = 'd$ n$' & end if amaj lt 1.41 then begin dx=1 & dx2=1 & frm = 'd$ n$' & end ;-------- Generate tick values -------------- if dx le 30 then begin ;---------- Labeled tick spacing LE 30 days ---------- majv = [0L] ; Major tick values array seed. minv = [0L] ; Major tick values array seed. for i = 0, n_elements(mjds)-1 do begin lo = mjds[i]-1+dx ; Start at day 0 + dx (skips 0). hi=mjde[i]-(dx<2) ; Stop before end. if dx le 2 then hi=mjde[i] ; For 1 day steps do all. if lo lt hi then begin ;majv = [majv, mjds[i],makei(lo,hi,dx)] ; RCJ 28Mar2018 In tests, not including that middle term ; to the array makes the labels better spaced ; when time range includes end of one month ; and beginning of the next. if mjds[i] le majv[n_elements(majv)-1]+dx then $ majv = [majv, makei(lo,hi,dx)] else $ majv = [majv, mjds[i],makei(lo,hi,dx)] endif else begin majv = [majv, mjds[i]] endelse lo = mjds[i]-1+dx2 hi = mjde[i] if lo lt hi then begin minv = [minv, mjds[i],makei(lo,hi,dx2)] endif else begin minv = [minv, mjds[i]] endelse endfor endif else begin ;-------- Labeled tick spacing GT 30 days ----------- minv = mjds ; Assume minor ticks are all month start JD. if dx eq 60 then begin majv = jdselect(mjds,['jan','mar','may','jul','sep','nov'],/mon) endif if dx eq 90 then begin majv = jdselect(mjds,['jan','apr','jul','oct'],/mon) endif if dx eq 180 then begin majv = jdselect(mjds,['jan','jul'],/mon) minv = jdselect(mjds,['apr','oct'],/mon) endif if dx eq 360 then begin majv = jdselect(mjds,['jan'],/mon) minv = jdselect(mjds,['apr','jul','oct'],/mon) endif if dx eq 720 then begin majv = jdselect(mjds,['jan'],/mon) minv = jdselect(mjds,['jul'],/mon) endif endelse ;-------- Trim tick values to range ---------- w = where((jd1 le majv) and (jd2 ge majv), c) if c gt 0 then majv = majv[w] w = where((jd1 le minv) and (jd2 ge minv), c) if c gt 0 then minv = minv[w] end