Multi-Panel Figures

Ferret distribution do not include any convenient scripts to make multi-panel figures.
In the past, I have posted two versions of a GO file to define multiple viewports in the Ferret email forum. It is surprising to learn that such usefull scripts posted in the Forum never makes way to later Ferret releases. The most recent version of my multi_view GO file is introduced in this post. This is one of the most frequently used GO files in my research work and I hope that you will find it useful.

Previous versions of multi_view GO file and details are available here and here. Its usage is pretty simple and straight forward, like :

CB --> corner box (for labeling a panel)

GO multi_view [rows],[columns],[xsize],[xstart],[xgap],[ysize],[ystart],[ygap],[view_name_prefix],[CB_xsize],[CB_ysize]

where,

rows : number of rows	colunms : numbr of columns
xsize : view size along X	ysize : view size along Y
xstart : xlo for lefternmost view	ystart : ylo for bottommost view
xgap : spacing between view along X	ygap : spacing between view along Y
prefix : prefix to view number (default is V)	CB_xsize : xsize for corner box
	CB_ysize : ysize for corner box

With multi_view, it is easy to :

• define desired number of viewports with given size and position
• place panel labels (like (A), (b) etc.) at panel corners
• remove unwanted white space between panels
• control spacing between figure axis and axis labels
• define viewports with same X-size but differnt Y-size (or vice versa) 
• make overlay plots with variables of different dimensions
• draw line legends on a time axis plot 

Few examples are shown below :

The demo script which generated these figures and the multi_view.jnl GO file are given towards the end of this post.

This figure has too much space between panels.	Tune [xgap] and [ygap] to remove extra space between panels.

Easy panel labeling within plot area.

Temperature (shading) has dimensions (X,Z) and mided layer depth (MLD,line) has dimension (X). This overlay plot is made by defining two identical viewports and  using first one for tempearture and second one for MLD.

 

For publications we may have to reduce figure size often. Here is a quick fix using multi_view by reducing the spacing between axis and its labels.

Both upper and lower panels have same X-axis and hence the same size, but Y-axes are different. Such "corresponding axis" plots are very easy with muti_view.

How many panels you need in a figure? This figure is made by few lines in Ferret and was possible only with multi_view. (Currently Ferret allow only 200 viewports at a time. Remember that multi_view always define 4 corner boxes for labelling. Hence this example has 9 rows x 4 colums = 36 main viewports, 36*4 = 144 corner viewports and a total of 180 viewports.)

multi_view GO file

Copy and save this as multi_view.jnl and place it in your ferret/go directory for easy access. Otherwise you can place it in a convenient location and update the path in ferret_paths file.

\ cancel mode verify ! ! DESCRIPTION: GO file to make multiple viewports with ! 1. desired size/position. ! 2. four corner boxes (per viewport) for labeling ! 3. polygon commands to choose background color ! and boundary line properties for corner boxes. ! ! REQUIRES : Ferret version 5.7 or higher (which supports /AXES qualifier ! to "define view" and /RANGE qualifier to "REPEAT" commands. ! ! Some typical bugs/problems and theirs fixes ! -------------------------------------- ! 1 segmentation fault : If you face this, and if you have a ! "set mode metafile" command, then add a "cancel mode meta" towards ! the end of the script. See ! http://ferret.pmel.noaa.gov/Ferret/Mail_Archives/fu_2006/msg00080.html ! ! 2 /SIGDIG qualifier to the CONTOUR command may not be effective ! sometimes. Then use the 4th argument to /LEVELS qualifier ! /LEVELS=(lo, hi, delta, ndigits) & the usage is ! ndigits = -1 for integer format ! = -3 to omit numerical labels ! = 1/2/ for valid precision/significant digits ! ! 3 blank/white regions at edges of viewport : do any of the following ! - tune /hlimits or /vlimits ! - tune "set reg" command (set is slightly bigger than hlimits ! or vlimits) ! - first shade and then overlay with fill ! - just repeat the script once again, in the same ferret session. ! Also see mails, starting with this one : ! http://www.pmel.noaa.gov/maillists/tmap/ferret_users/fu_2005/msg00148.html ! ! 4 some times polygone commands ( ($polfl) or ($poll) ) does not work. Then ! - issue the polygon command twice. See example 2 below. ! ! 5. In some cases the polygon command will change colors of already drawn plots, ! on the screen (especially if you use rgb_colors go file). However, the ! metafile and resulting ps file will be just fine, but the gif file ! (FRAME/FILE=mygiffile.gif) will be in bad shape. ! ! NOTES ! 1. To define two sets of viewports with similar features (position & size), ! call multi_view two times with different values ONLY for the 9th ! argument. See example 2 below. ! ! 2. The ordering of viewports is shown towards the end of these comments. ! ! 3. The corer box will have suffixes like ("*" is the viewport name). ! *_bl : bottom left ! *_br : bottom right ! *_tr : top right ! *_tl : top left ! ! To put labels inside the corner boxes, use the predefined polygon ! commands ( ($polfl) and ($poll) ). Remember that: 1. Xaxis and ! Yaxis varies from 1 to 10, 2. xpol and ypol are variables to polygon ! command ! ! set view v11_bl ! ($polfl)/palette=white/color=1 xpol, ypol ! white background ! label 4.5, 4.5, 0, 0, 0.35 @C010(a) ! ! 4. While using ($polfl), be careful not to give any commands which will ! alter the default ferret behavior (like using palette within /SET ! environment and commands like "ppl tics" etc.). ! ! Default 1 : Just "go multi_view" (ie without any arguments) will define 15 ! Behavior viewports in 5 rows and 3 columns with names v11, v12,...v53 ! ! 2 : There is no mandatory arguments for this go file ; all ! arguments are optional. ! ! $1 $2 $3 $4 $5 $6 $7 ! USAGE : go multi_view [rows],[columns],[xsize],[xstart],[xgap],[ysize],[ystart] ! [ygap],[view_name_prefix],[CB_xsize],[CB_ysize] ! $8 $9 $10 $11 ! ! CB -> Corner Box ! ! rows : number of rows columns : number of columns ! xsize : view size along X ysize : view size along Y ! xstart: xlo for lefternmost view ystart : ylo for bottommost view ! xgap : spacing of view along X ygap : spacing of view along Y ! prefix: prefix to view number CB_xsize : xsize for corner box ! default is "V" CB_ysize : ysize for corner box ! ! EXAMPLE 1: ! 6 viewports of similar size ! use coads_climatology ! set reg/l=1/x=30:120/y=-30:30 ! set window/aspect=1.3 ! go multi_view 5, 3, 0.25, 0.1, 0.03, 0.15, 0.10, 0.02, , 0.05,0.035 ! set view v11 ; ppl axlabp 1,-1 ; fill/nolab/line sst ! set view v12 ; ppl axlabp 1, 0 ; fill/nolab/line sst ! set view v13 ; ppl axlabp 1, 1 ; fill/nolab/line sst ! set view v21 ; ppl axlabp -1,-1 ; fill/nolab/line sst ! set view v22 ; ppl axlabp -1, 0 ; fill/nolab/line sst ! set view v23 ; ppl axlabp -1, 1 ; fill/nolab/line sst ! !How to use the corner boxes for labeling ? ! ! polfl --> think about polygon/fill/line ! ! poll --> think about polygon/line ! set view v22_bl ! ($polfl)/pal=white/COLOR=1 xpol, ypol ! label 4.3,4.3,0,0,0.35 @C010 (a) ! set view v23_br ! ($polfl)/palette=black/COLOR=1 xpol, ypol ! label 4.3,4.3,0,0,0.35 @C011 (b) ! ! Example 2: ! 2 sets of viewports, to plot MLD over depth-lat/lon section of temp. ! use levitus_climatology ! let zero_at_mld = temp[d=1] - (temp[d=1,k=1]-1) ! let mld = zero_at_mld[Z=@LOC:0] ! go multi_view 1,2,0.30,0.12,0.03,0.35,0.4,0.01,VL,0.045,0.045 ! go multi_view 1,2,0.30,0.12,0.03,0.35,0.4,0.01,VR,0.045,0.045 ! palette=orange_purple ; PPL AXLSZE 0.12,0.12 ; PPL AXNMTC 1,1 ! ! set view VL11 ; ppl axlabp -1,-1 ! fill/vlim=0:150:20/hlim=54.5:75.5:5/nolab/lev=(15,29,1)/nokey temp[y=6N] ! set view VR11 ! plot/vlim=150:0:20/hlim=54.5:75.5:5/nolab/noaxes/color=10 mld[y=6N] ! set view VL11_bl ! ($poll)/color=1 xpol, ypol ; ($poll)/color=1 xpol, ypol ! label 4.5,4.5,0,0,0.38 @C008 (a) ! ! set view VL12 ; ppl axlabp -1,0 ! fill/vlim=0:150:20/hlim=79.5:100.5:5/nolab/lev=(15,29,1) temp[y=6S] ! set view VR12 ! plot/vlim=150:0:20/hlim=79.5:100.5:5/nolab/noaxes/color=10 mld[y=6S] ! set view VL12_bl ! ($polfl)/palette=white xpol, ypol ; ($polfl)/palette=white xpol, ypol ! label 4.5,4.5,0,0,0.38 @C008 (b) !------------------------------------------------------------------------------ ! ! +-------+-------+-------+ ! Written By : Jaison Kurian ! v11 | v12 | v13 | ! Contact : jaisonkurian@gmail.com +-------+-------+-------+ ! ! v21 | v22 | v23 | ! Version : multi_view +-------+-------+-------+ ! Date : 27-FEB-2006 ! v31 | v32 | v33 | ! Comments : None +-------+-------+-------+ ! Modifications : 2 ! v41 | v42 | v43 | ! +-------+-------+-------+ ! ! v51 | v52 | v53 | ! +-------+-------+-------+ ! Modifications : ! --------------- ! 1. On 15/Nov/2006 : Corner boxes for figure labelling have been added ! with two additional arguments ($10 & $11). ! ! +---+---------+ +-------------+ +-------------+ +---------+---+ ! | A | | | | | | | | D | ! |---+ | | | | | | +---| ! | | | | | | | | ! | | |---+ | | +---| | | ! | | | B | | | | C | | | ! +-------------+ +---+---------+ +---------+---+ +-------------+ ! ! 2. On 14/Jun/2007 : Polygon commands were added to make the Figure labelling ! easy (symbols "polfl" and "poll"). ! !------------------------------------------------------------------------------- ! ! define internal variables !     define symbol mv_r = $1"5" ! number of rows     define symbol mv_c = $2"3" ! number of columns     define symbol mv_xs = $3"0.25" ! X size     define symbol mv_xb = $4"0.10" ! X beginning     define symbol mv_xg = $5"0.03" ! X gap     define symbol mv_ys = $6"0.15" ! Y size     define symbol mv_yb = $7"0.10" ! Y beginning     define symbol mv_yg = $8"0.02" ! Y gap     define symbol mv_prefx= $9"v" ! Prefix for the viewport name     define symbol mv_cbw = $10"0.07" ! Corner box width     define symbol mv_cbh = $11"0.07" ! Corner box height ! ! Issue a warning message if request values does not fit in !     let mv_xh = `($mv_xb)+($mv_c)*($mv_xs)+(($mv_c)-1)*($mv_xg)` ! X high     let mv_yh = `($mv_yb)+($mv_r)*($mv_ys)+(($mv_r)-1)*($mv_yg)` ! Y high     IF `($mv_r) LT 1` THEN ! minimum number of rows is 1           SAY ; SAY " ERROR (multi_view) : Number of rows should be > 0" ; SAY           EXIT/PROMPT     ENDIF     IF `($mv_c) LT 1` THEN ! minimum number of columns is 1           SAY ; SAY " ERROR (multi_view) : Number of columns should be > 0" ; SAY           EXIT/PROMPT     ENDIF     IF `($mv_xb) GT 0.9 OR ($mv_xb) LT 0` THEN ! upper/lower bound for xstart           SAY ; SAY " ERROR (multi_view) : X_Start should be between 0.0 and 0.9" ; SAY           EXIT/PROMPT     ENDIF     IF `($mv_yb) GT 0.9 OR ($mv_yb) LT 0` THEN ! upper/lower bound for ystart           SAY ; SAY " ERROR (multi_view) : Y_Start should be between 0.0 and 0.9" ; SAY           EXIT/PROMPT     ENDIF     IF `mv_xh GT 1.0` THEN           SAY           SAY " ERROR (multi_view) : Exceeded Max Xsize --> "           SAY " Reduce Number of Columns or Xsize/Xstart/Xgap...."           SAY ; EXIT/PROMPT     ENDIF     IF `mv_yh GT 1.0` THEN           SAY           SAY " ERROR (multi_view) : Exceeded Max Ysize --> "           SAY " Reduce Number of Rows or Ysize/Ystart/Ygap...."           SAY ; EXIT/PROMPT     ENDIF     IF `($mv_cbh) GE ($mv_ys)` THEN           SAY           SAY " ERROR (multi_view) : Corner Box Height is > Ysize --> "           SAY " Reduce Corner Box Height (arg 11) or increase Ysize (arg 6)."           SAY ; EXIT/PROMPT     ENDIF     IF `($mv_cbw) GE ($mv_xs)` THEN           SAY           SAY " ERROR (multi_view) : Corner Box Width is > Xsize --> "           SAY " Reduce Corner Box Width (arg 10) or increase Xsize (arg 3)."           SAY ; EXIT/PROMPT     ENDIF ! ! IF arguments are valid, define the viewports !     REPEAT/RANGE=1:`($mv_r)`:1/NAME=mv_ro ( ;\        let mv_ylo = ($mv_yb) + (($mv_r)-`mv_ro`)*($mv_yg) + (($mv_r)-`mv_ro`)*($mv_ys) ;\        let mv_yhi = ($mv_yb) + (($mv_r)-`mv_ro`)*($mv_yg) + (($mv_r)-(`mv_ro`-1))*($mv_ys) ;\        REPEAT/RANGE=1:`($mv_c)`:1/NAME=mv_co ( ;\           let mv_xlo = ($mv_xb) + (`mv_co`-1)*($mv_xg) + (`mv_co`-1)*($mv_xs) ;\           let mv_xhi = ($mv_xb) + (`mv_co`-1)*($mv_xg) + `mv_co`*($mv_xs) ;\           define view/axes/xlim=`mv_xlo`:`mv_xhi`/ylim=`mv_ylo`:`mv_yhi` ($mv_prefx)`mv_ro``mv_co` ;\           define view/axes/xlim=`mv_xlo`:`mv_xlo+($mv_cbw)`/ylim=`mv_ylo`:`mv_ylo+($mv_cbh)` ($mv_prefx)`mv_ro``mv_co`_bl ;\           define view/axes/xlim=`mv_xhi-($mv_cbw)`:`mv_xhi`/ylim=`mv_ylo`:`mv_ylo+($mv_cbh)` ($mv_prefx)`mv_ro``mv_co`_br ;\           define view/axes/xlim=`mv_xlo`:`mv_xlo+($mv_cbw)`/ylim=`mv_yhi-($mv_cbh)`:`mv_yhi` ($mv_prefx)`mv_ro``mv_co`_tl ;\           define view/axes/xlim=`mv_xhi-($mv_cbw)`:`mv_xhi`/ylim=`mv_yhi-($mv_cbh)`:`mv_yhi` ($mv_prefx)`mv_ro``mv_co`_tr ;\        ) ;\     ) ! ! Define few polygon commands which will make the labelling easy !      define symbol polfl = POLYGON/fill/line/noaxes/nolab/nokey/vlim=1:10/hlim=1:10      define symbol poll = POLYGON/line/noaxes/nolab/nokey/vlim=1:10/hlim=1:10      let xpol = XSEQUENCE({1,10,10,1,1})      let ypol = XSEQUENCE({1,1,10,10,1}) ! ! Clean Up !     cancel variable mv_* ; cancel symbol mv_*     set mode/last verify


multi_view demo script

Copy and save this as multi_view_demo.jnl and give a try (this one needs access to multi_view.jnl, coads_climatology.cdf and levitus_climatology.cdf).

\ cancel mode verify ! ! Description : Demo file to show the capabalities and usage of multi_view ! GO file. ! ! Requires : multi_view.jnl, coads_climatology, levitus_climatology in pwd ! or Ferret search path. ! ! Usage : yes? go multi_view_demo ! ! Warning : please do not run this script repeatedly in the same Ferret ! session ! ! Written By : Jaison Kurian (jaisonkurian@gmail.com) ! Written On : 16/June/2007 ! Comments : None ! Modifications : Mar/03/2012 : Newever version of Ferret allows onlu 200 ! predefined viewports. Hence the last example in this ! demo has 9x4 viewports (ie 9x4x5=180 viewports including ! corner ones) instead of 10x6 as in earlier version. ! !------------------------------------------------------------------------- \ set mode verify    ! SOME INITIAL SET UP         use coads_climatology         set reg/x=30:120/y=-30:30/k=1         palette=rainbow2_cmyk         set window/clear \ pause    ! LET US DEFINE 4 VIEWPORTS : 2 ROW & 2 COLUMN    ! WITH MINIMAL ARGUMENTS.....         go multi_view 2, 2, 0.34, 0.12, 0.05, 0.34, 0.12, 0.05 \ pause    ! LET US MAKE A PLOT IN UPPER LEFT VIEW : V11 --> DEFAULT NAME         set view v11 ; ppl axlabp 1,-1             fill/lev="(20,28,0.5),(28,30,0.25)"/nolab/nokey sst[l=3]             go land \ pause    ! NOW, IN UPPER RIGHT VIEW : V12 --> DEFAULT NAME         set view v12 ; ppl axlabp 1,1             fill/lev="(20,28,0.5),(28,30,0.25)"/nolab/nokey sst[l=4]             go land \ pause    ! NOW, IN LOWER TWO : V21 & V22         set view v21 ; ppl axlabp -1,-1             fill/lev="(20,28,0.5),(28,30,0.25)"/nolab/nokey sst[l=5]             go land         set view v22 ; ppl axlabp -1,1             fill/lev="(20,28,0.5),(28,30,0.25)"/nolab/nokey sst[l=6]             go land \ pause    ! THERE IS LOT OF WHITE SPACE BETWEEN THE VIEWPORTS. LET US REMOVE    ! IT BY ADJUSTING "xgap" and "ygap"    ! go multi_view 2, 2, 0.34, 0.12, 0.05, 0.34, 0.12, 0.05 Prev. one    ! #### ####         go multi_view 2, 2, 0.34, 0.12, 0.025,0.34, 0.12, 0.03, vv    ! THE LAST ARGUMENT "vv" is used here just to avoid    ! "Re-defining viewport" Message on terminal. \ pause \ ppl shaset reset ; set window/clear         set view vv11 ; ppl axlabp 1,-1             fill/lev="(20,28,0.5),(28,30,0.25)"/nolab/nokey sst[l=3]             go land         set view vv12 ; ppl axlabp 1,1             fill/lev="(20,28,0.5),(28,30,0.25)"/nolab/nokey sst[l=4]             go land         set view vv21 ; ppl axlabp -1,-1             fill/lev="(20,28,0.5),(28,30,0.25)"/nolab/nokey sst[l=5]             go land         set view vv22 ; ppl axlabp -1,1             fill/lev="(20,28,0.5),(28,30,0.25)"/nolab/nokey sst[l=6]             go land \ pause !---------------------------------------------------------------------------- \ set reg/x=150:280/y=-20:20/k=1    ! NOW LET US SEE HOW TO INSERT FIGURE NUMBER AT CORNERS OF VIEWPORT         go multi_view 2, 2, 0.34, 0.12, 0.025,0.34, 0.12, 0.03, vb \ ppl shaset reset ; set window/clear         set view vb11 ; ppl axlabp 1,-1             fill/lev="(20,28,0.5),(28,30,0.25)"/nolab/nokey sst[l=3]             go land    ! LET US PLACE THE LABEL ON BOTTOM-LEFT CORNER. REMEBMER THAT THE    ! X & Y AXES OF THE SMALL CORNER BOX VARIES FROM 1-10 FOR    ! EASY "x","y" VALUES FOR THE LABEL COMMAND    ! vb11_bl --> "vb11" is parent view and "_bl" indicates BOTTOM-LEFT    ! ($polfl) --> POLYGONE/FILL/LINE predefined polygon command    ! xpol --> predefined polygon x-variable    ! ypol --> predefined polygon y-variable    ! ALWAYS USE VERY BIG FONT SIZE SINCE THE VIEWPORT SIZE IS VERY SMALL \ pause         set view vb11_bl         ($polfl)/pal=white/color=1 xpol, ypol         label 5,4.5,0,0,0.55 @C007A \ pause    ! LET US TUNE THE FIGURE NUMBER AREA    ! go multi_view 2, 2, 0.34, 0.12, 0.025,0.34, 0.12, 0.03, vb Prev. one    ! ## ##       go multi_view 2, 2, 0.34, 0.12, 0.025,0.34, 0.12, 0.03, vc, 0.04, 0.05 \ pause \ set window/clear         set view vc11 ; ppl axlabp 1,-1             fill/lev="(20,28,0.5),(28,30,0.25)"/nolab/nokey sst[l=3]             go land             set view vc11_bl             ($polfl)/pal=white/color=1 xpol, ypol             label 5,4.2,0,0,0.50 @C007A \ pause    ! NUMBERING WITH ONLY BOX LINING             set view vc11_tl             ($poll)/color=1 xpol, ypol             label 5,4.2,0,0,0.50 @C010B \ pause !---------------------------------------------------------------------------- \ use levitus_climatology ; cancel reg/all \ let zero_at_mld = temp[d=2] - (temp[d=2,k=1]-1) \ let mld = zero_at_mld[Z=@LOC:0] \ palette=orange_purple ; PPL AXLSZE 0.12,0.12 ; PPL AXNMTC 1,1    ! LET US PLOT MLD OVER A DEPTH-LAT/LON SECTION OF TEMPERATURE.    ! HERE WE WILL DEFINE TWO IDENTICAL VIEWPORTS, WITH DIFFERENT    ! NAMES.    ! ##    go multi_view 1,2,0.30,0.12,0.06,0.35,0.4,0.01,VL,0.045,0.045    go multi_view 1,2,0.30,0.12,0.06,0.35,0.4,0.01,VR,0.045,0.045    ! PLEASE NOTE THAT WE WILL USE REVERSED /VLIMITS for MLD \ pause ; set window/clear    set view VL11 ; ppl axlabp -1,-1      fill/vlim=0:150:20/hlim=54.5:75.5:5/nolab/lev=(15,29,1)/nokey temp[y=6N]    set view VR11      plot/vlim=150:0:20/hlim=54.5:75.5:5/nolab/noaxes/color=10 mld[y=6N]    ! LET US MAKE ONE MORE PLOT \ pause    set view VL12 ; ppl axlabp -1,0      fill/vlim=0:150:20/hlim=79.5:100.5:5/nolab/lev=(15,29,1) temp[y=6S]    set view VR12      plot/vlim=150:0:20/hlim=79.5:100.5:5/nolab/noaxes/color=10 mld[y=6S] !----------------------------------------------------------------------------   ! Suppose you want to adjust axis labels without wasting precious journal   ! space.....here is a small trick   ! See the Y-axis time labels in the following plot --> \ set reg/y=-2:2/x=42.5:100   go multi_view 1,1,0.45,0.12,0.01,0.35,0.50,0.01,vbb \ pause ; set window/clear   set view vbb11 ; ppl axlabp -1,-1 ; ppl txlabp -1      fill/line/pal=yellow_orange_brown\                    /nolab/lev=(1009,1015,0.5) slp[d=1,j=@AVE] \ pause   ! We can tune it slightly....right ??   ! Here is the trick : Define two identical view ports with different   ! names.   go multi_view 1,1,0.45,0.12,0.01,0.35,0.10,0.01,vvb   go multi_view 1,1,0.45,0.12,0.01,0.35,0.10,0.01,vvc   ! use the first view to make the plot without Y-axis labels \ pause   set view vvb11 ; ppl axlabp -1,0 ; ppl txlabp 0      fill/line/pal=yellow_orange_brown\                    /nolab/lev=(1009,1015,0.5) slp[d=1,j=@AVE] \ pause   ! prepare the label fields   let mnames = TSEQUENCE({"J","F","M","A","M","J","J","A","S","O","N","D"})   ! use the second "dummy view to make an EMPTY plot   ! choose /vlimits=0:12 for easy y-coordinate values for labelling \ pause   ! Looks good ??   set view vvc11       plot/vs/nolab/noaxes/vlimits=0:12/hlimits=1:10 100,100       REPEAT/RANGE=1:12:1/NAME=yyl (;\          define symbol mm = `yyl` ;\          label 0.8,`($mm)-0.5`,0,90,0.12 @C001`mnames[l=($mm)]` ;\       ) !---------------------------------------------------------------------------- ! TWO different viewports side by side ! ! Say you want to plot the zonal section of temperature and place a ! time series of wind zonal wind speed, in such a way that there ! is direct correspondence between longitudes. ! ! BIGGER view at bottom for temperature section ! SMALLER view at top for zonal wind time series \ pause ; set reg/Y=10/Z=0:300/l=6 ! good to start with the BIGGER BOTTOM plot --> VBOT ! ## ## ##       go multi_view 1, 1, 0.55, 0.15, 0.01, 0.40, 0.20, 0.01, VBOT \ pause ; set window/clear ; ppl axlint 2,2 ; ppl axnmtc 0,0       set view VBOT11 ; ppl axlabp -1,-1 ; ppl axlsze 0.11,0.11          fill/hlim=54:74:2/lev=(10,29,1)/nolab temp[d=2] ! How to define a matching viewport for time series? ! ! for VB above, we had : ysize = 0.40 ! ystart = 0.20 ! ygap = 0.01 ! ! --> the ystart for next view should be sum of above 3 plus the ! required gap between viewports (let it be 0.03), then ! 0.40 + 0.20 + 0.01 = 0.61 ; 0.61+0.03 = 0.64 ! ! --> the x variables (xsize, xstart, xgap) will REMAIN THE SAME ! ! Let us define the top view, with a ysize of 0.15 and ystart of 0.64    ! ysize, ystart    ! go multi_view 1, 1, 0.55, 0.15, 0.01, 0.40, 0.20, 0.01, VBOT    ! ## ##       go multi_view 1, 1, 0.55, 0.15, 0.01, 0.15, 0.64, 0.01, VTOP \ pause       set view VTOP11 ; ppl axlabp 1,-1 ; ppl axlsze 0.13,0.13          plot/hlim=54:74:2/vlim=6:10/color=2/nolab uwnd[d=1] !---------------------------------------------------------------------------- \ pause ; set reg/l=1:12 ; set window/clear ; cancel viewport v*      ! Drawing LINE LEGENDS on time a time seris plot is not that easy. Lest us      ! see how we can do it comfortably with multi_view.      ! Define the main viewport and make 3 time series plots      go multi_view 1,1,0.7,0.15,0.01,0.32,0.40,0.01,vts,0.03,0.04      set view vts11         plot/vlim=26:31:0.5/nolab/color=1 sst[d=1,x=60,y=10]         plot/vlim=26:31:0.5/nolab/ov/color=2 sst[d=1,x=90,y=10]         plot/vlim=26:31:0.5/nolab/ov/color=4 sst[d=1,x=150,y=10] \ pause      ! Let us put the line legends within the plot area, to the top.      ! --> define a similar viewport, with adjusted y-parameters      ! go multi_view 1,1,0.7,0.15,0.01,0.32,0.40,0.01,vts,0.03,0.04      ! ### ### ###        go multi_view 1,1,0.7,0.15,0.01,0.12,0.65,0.01,vlg,0.03,0.04      ! remember that the variables xpol and ypol varies 1-10 --> hence      ! you can easily pick the positions of lines and labels here. \ pause      set view vlg11         ($poll)/axes=0,0,0,0 xpol*0+100, ypol*+100         plot/vs/over/line/nolab/color=1 {2,3},{3,3}         label 3.2,2.8,-1,0,0.15 60^0E         plot/vs/over/line/nolab/color=2 {4,5},{3,3}         label 5.2,2.8,-1,0,0.15 90^0E         plot/vs/over/line/nolab/color=4 {6,7},{3,3}         label 7.2,2.8,-1,0,0.15 150^0E \ pause !----------------------------------------------------------------------------   ! HERE IS THE FINAL SHOW OFF.....   ! Question : Can you define 36 (read it carefully..ok "36") viewports   ! on a Ferret window ??   !   ! Suppose you had the patience to sit and write 36 lines of   ! "define view" with arguments calculated to the 3rd or 4th   ! presion.....using your computer ...... and to make plots   ! in that viewports......fine.   !   ! If somebody ask you to change the spacing between viewports   ! "little bit" or increase the view size "slightly".....what   ! will be your response ?? .......excuse me..   !   ! with multi_view it will take only < 1 minute ....   !   ! HERE YOU GO...........    cancel viewports    go multi_view 9,4,0.215,0.10,0.008,0.093,0.1,0.006, VS \ pause \ cancel mode verify    set reg/x=30:120/y=-30:30    palette=rainbow2_cmyk    set window/aspect=1.3 ; set window/clear       ! sometimes ferret ppl commands won't work if it has been       ! use multiple times in a ferret session....the trick is       ! to repeat it as shown below    ppl axlint 0,0 ; ppl axnmtc 0, 0 ; ppl axlabp 0, 0 ; ppl tics ,,,,1,1    let count = 0    REPEAT/RANGE=1:9:1/NAME=nrow (;\        REPEAT/RANGE=1:4:1/NAME=ncol (;\           let count = `count` + 1 ;\           let m_id = IF `count/12 GT 1` THEN `count-12*int((count-1)/12)` ELSE `count` ;\           set view VS`nrow``ncol` ;\           fill/lev=(20,30,1)/nolab/nokey sst[l=`m_id`,d=1] ;\           go land ;\           ppl shaset reset ;\        ) ;\    )   say ; say " ADIOS......." ; say

About this blog : My Ferret Plot

This blog is to share some of my experiences/tips/tricks with the scientific data visualization and analysis tool Ferret. You will also see many other helpfull computer related information on oceanographic research in this blog.
 
Ferret is a free data analysis and visualization tool primarily designed for oceanographers and meteorologists by PMEL NOAA. Ferret has its own advantages and disadvantages compared to other tools popular among earth science community like Matlab, NCL, GrADS, GMT, Python etc. In the last several years of use, i like Ferret for its simplicity and the quality of its graphics. However, Ferret is extremely disappointing in terms of serious data analysis due to its "delayed mode evaluation" (ie. all expressions are evaluated only when Ferret sees an action command like "plot"). For this reason I use Matlab/Fortran for data analysis and Ferret is mainly reserved for generating graphics. However, there are situations where Ferret can be quite handy, if you know how to use it properly (a good example is finding climatology from a time series, Ferret could do that in few lines of script). I will share some of my experience/trips/tricks with Ferret through this blog.

You can find all my posts in the Ferret email forum here (search for my name "Jaison Kurian").

Here is a nice Ferret plot using enhanced shading intervals for smoother colors and data filling to remove data gaps near land boundary. Please see the script used for generating this figure below.



\ cancel mode verify      set data levitus_climatology ! load data      let temp_fln = temp[d=1,k=1,i=@FLN:15,j=@FLN:15] ! Linear interpolation to fill gaps                                           ! between data & land boundary      let temp_fill = temp_fln[j=@FNR] ! additional filling using nearest neighbor      define symbol flev = "(-inf)(-2,20,1)(20.5,29,0.5)(inf)" ! fill levels      define symbol clv = "(28,28,1)" ! cont levels      define symbol hl = 20.5:379.5:30 ! hlimits      define symbol vl = -89.5:89.5:20 ! vlimits      define symbol pal = rainbow2_cmyk.spk ! palette      ppl axlint 2,1 ! axis label interval      ppl axnmtc 1,1 ! axis minor tics      ppl axlsze 0.112,0.112 ! axis label size      ppl color 6,73,73,73 ! new color      fill/pal=($pal)/lev=($flev)/hlim=($hl)/vlim=($vl)/nolab temp_fill      contour/ov/nolab/lev=($clv)/spacing=1.5/size=0.115/color=1 temp_fill      plot/vs/line/color=6/nolab/ov {20.5,379.5},{0,0} ! draw equator-line      go fland 20 black ! fill land      label `(379.5+20.5)/2`,95,0,0,0.18 @C001 Sea Surface Temperature (^oC) : Levitus Climatology      ! frame/file=sst_gbl.gif ! uncomment for gif outpu