[gradsusr] how to find typhoon center via minloc function
sushant puranik
sushantpuranik at gmail.com
Fri Apr 29 08:32:14 EDT 2011
Hello Charles
I want to make a jet stream plot. Can i make it with the help of hurricane
center script by changing minloc and min to maxloc and max.
any suggestion?
thanks
Sushant
On Wed, Jan 5, 2011 at 1:01 AM, Charles Seman <Charles.Seman at noaa.gov>wrote:
> Jie,
>
> Attached is a file File_Error_1_Grads_1.9-Plot_tc_shi.gs.txt containing the
> text from an email exchange to the GrADS Listserv between Joe Covert and
> Diane Stokes on 9/13/2004 -- on 4/27/06, found via a Google search for "
> plot_tc_shi.gs": http://caos.iisc.ernet.in/gslib/plot_tc_shi.gs
>
> The attached GrADS script plot_hurricane_center3.gs (along with pause.gsf,
> aGrADS script function used by the plot script) is a locally modified
> version derived from Joe Covert's script "plot_tc_shi.gs" (
> Joe.Covert at noaa.gov) which was posted to the GrADS Listserv on 9/13/2004
> (his script was named plot_tc_shi.gs) and code from hurricane_tracking.txt
> (taken from an email exchange posted to the GrADS Listserv by Kun-Hsuan Chou
> and Arturo Caracas Uribe in Oct, 2004)...
>
> Please find below code from hurricane_tracking.txt (taken from an email
> exchange posted to the GrADS Listserv by Kun-Hsuan Chou and Arturo Caracas
> Uribe in Oct, 2004) illustrating a technique for finding max wind in a 2D
> field... and below that some code from attached script
> plot_hurricane_center3.gs to find the min sea-level pressure in a 2D
> field...
>
> code from Kun-Hsuan Chou to find maximum wind speed from
> hurricane_tracking.txt:
> ---
> 'd maxloc(max(mag(u,v),lon=120,lon=130),lat=15,lat=25)'
> line=sublin(result,2)
> ygrd=subwrd(line,4)
> 'd maxloc(max(mag(u,v),lat=15,lat=25),lon=120,lon=130)'
> line=sublin(result,2)
> xgrd=subwrd(line,4)
> 'set x 'xgrd
> lonval = subwrd(result,4)
> 'set y 'ygrd
> latval = subwrd(result,4)
> 'q w2xy 'lonval' 'latval
> xpos = subwrd(result,3)
> ypos = subwrd(result,6)
> 'draw mark 1 'xpos' 'ypos' .2'
> ---
>
> sample code from plot_hurricane_center3.gs to find hurricane center (see
> script for supporting code):
> ---
> *
> * find minimum "pressure" within box area (x1,x2), (y1,y2)...
> *
> 'set x 'x1
> 'set y 'y1
> 'set z 1'
> 'set t 'tt
> 'set gxout print'
> nxp = x2-x1+1
> * say ' nxp = 'nxp
> nyp = y2-y1+1
> * say ' nyp = 'nyp
> 'd minloc(min(psl,y='y1',y='y2'),x='x1',x='x2')'
> rec=sublin(result,nxp+3)
> xc=subwrd(rec,1)
> 'd minloc(min(psl,x='x1',x='x2'),y='y1',y='y2')'
> rec=sublin(result,nyp+3)
> yc=subwrd(rec,1)
> say
> say 'location of minimum "pressure"...'
> say
> say ' (xc,yc) = ('xc','yc')'
> *
> * find "world" coordinates of (xc,yc) and convert "world" coordinates
> * to "xy" coordinates for plotting track of hurricane center...
> *
> 'set x 'xc
> lonval = subwrd(result,4)
> 'set y 'yc
> latval = subwrd(result,4)
> say ' (lonval,latval) = ('lonval','latval')'
> 'q w2xy 'lonval' 'latval
> xpos = subwrd(result,3)
> ypos = subwrd(result,6)
> say ' (xpos,ypos) = ('xpos','ypos')'
> *
> * write (xpos,ypos) to output file...
> *
> res = write (''hurricane.nf'','t = 'tt' xpos = 'xpos' ypos = 'ypos'')
>
> pause()
> ---
>
> Please let me know if you have any questions.
>
> Hope this helps,
> Chuck
>
> Jie TANG wrote:
>
>>
>> hi,grads folks ,
>> I am using grads v1.9, trying to find the center of typhoon via minloc
>> function.
>> the key script is shown as below:
>> slplat=min(slp,lat=19,lat=26)
>> tclon=minloc(slplat,lon=119,lon=126)
>> slplon=min(slp,lon=119,lon=126)
>> tclat=minloc(slplon,lat=19,lat=26)
>>
>> but grads tell me that "function not found min " and when i changed my
>> script to be :
>> tclat=min(minloc(slpt,lon=119,lon=126), lat=19,lat=26)
>> tclon=min(minloc(slpt, lat=19,lat=26 )lon=119,lon=126)
>>
>>
>> how can i finx my scrpit ? thank you .:)
>> --
>>
>> TANG Jie
>> Email: totangjie at gmail.com <mailto:totangjie at gmail.com>
>>
>> Tel: 0086-2154896104
>> Shanghai Typhoon Institute,China
>> ------------------------------------------------------------------------
>>
>> _______________________________________________
>> gradsusr mailing list
>> gradsusr at gradsusr.org
>> http://gradsusr.org/mailman/listinfo/gradsusr
>>
>>
>
> --
>
> Please note that Charles.Seman at noaa.gov should be considered my NOAA
> email address, not cjs at gfdl.noaa.gov.
>
> ********************************************************************
> Charles Seman Charles.Seman at noaa.gov
> U.S. Department of Commerce / NOAA / OAR
> Geophysical Fluid Dynamics Laboratory voice: (609) 452-6547
> 201 Forrestal Road fax: (609) 987-5063
> Princeton, NJ 08540-6649 http://www.gfdl.noaa.gov/~cjs/
> ********************************************************************
>
> "The contents of this message are mine personally and do not reflect any
> official or unofficial position of the United States Federal Government,
> the United States Department of Commerce, or NOAA."
>
>
>
> worked great ... thanks. joe
>
> Diane Stokes wrote:
>
> > Joe,
> >
> > Read works fine for me in 1.9.
> >
> > I think this is the issue where 'pull' in 1.9 throws in a carriage
> > return. The read statement is not getting the exact filename.
> >
> > Try adding:
> > file=sublin(file,1)
> > after each:
> > pull file
> >
> > Diane
> >
> > Joe Covert wrote:
> >
> >> There appears to be a problem with version 1.9 of GrADS "read" function.
> >>
> >> The plot_tc_shi.gs script (see below) uses the read function to open
> the
> >> track data file and the program gives the subject error message "File
> >> Error 1".
> >>
> >> jc
> >>
> >>
> >> * Script to draw an hurricane-track plot.
> >> * Does little error checking on the input file.
> >> * Assumes the input file is set up as follows:
> >> *
> >> * Line 1: Title
> >> * Line 2: Drawing primitives for marks: marktype size
> >> * Line 3: Drawing primitives for lines: color style thickness
> >> * Line 4: Starting hour and the interval of plotting points
> >> * e.g., 0 6 means that track starts at 0 hour and mark
> >> * will be plotted every 6 hours.
> >> * Rest of lines: hour long. lat.
> >> * e.g., 0 -70.5 25.0
> >> * 6 -71.8 25.2
> >> * :
> >> * :
> >> *
> >> * Also assumes that a file has been opened (any file, doesn't
> >> * matter -- the set command doesn't work until a file has been
> >> * opened).
> >> *
> >>
> >> function main()
> >>
> >> * 'clear'
> >>
> >> 'open dummy.ctl'
> >> 'set lat 20 50'
> >> 'set lon -90 -30'
> >> 'set mpdset hires'
> >> 'set poli on'
> >> 'draw map'
> >>
> >>
> >> say 'Enter File Name: (type q to stop)'
> >> pull fname
> >>
> >> while (fname != 'q')
> >>
> >> * Read the 1st record: Title
> >>
> >> ret = read(fname)
> >> rc = sublin(ret,1)
> >> if (rc>0)
> >> say 'File Error 1'
> >> return
> >> endif
> >> title = sublin(ret,2)
> >> say title
> >>
> >> * Read the drawing primitives
> >>
> >> ret = read(fname)
> >> rc = sublin(ret,1)
> >> if (rc>0)
> >> say 'File Error 2'
> >> return
> >> endif
> >> dpline = sublin(ret,2)
> >> marktype = subwrd(dpline,1)
> >> marksize = subwrd(dpline,2)
> >> ret = read(fname)
> >> rc = sublin(ret,1)
> >> if (rc>0)
> >> say 'File Error 3'
> >> return
> >> endif
> >> dpline = sublin(ret,2)
> >> lcolor = subwrd(dpline,1)
> >> lstyle = subwrd(dpline,2)
> >> lthick = subwrd(dpline,3)
> >> say ' marktype, marksize, lcolor, lstyle and lthick:'
> >> say ' 'marktype ' ' marksize ' ' lcolor ' ' lstyle ' ' lthick
> >>
> >> * Read starting hour and the interval hours of plotting points
> >>
> >> ret = read(fname)
> >> rc = sublin(ret,1)
> >> if (rc>0)
> >> say 'File Error 4'
> >> return
> >> endif
> >> dhour = sublin(ret,2)
> >> start = subwrd(dhour,1)
> >> jump = subwrd(dhour,2)
> >> say ' starting hour and the interval hours of plotting points:'
> >> say ' 'start' 'jump
> >>
> >> * Read all data points
> >>
> >> ret = read(fname)
> >> rc = sublin(ret,1)
> >> while (rc = 0)
> >> loc = sublin(ret,2)
> >> hour = subwrd(loc,1)
> >> dlong.hour = subwrd(loc,2)
> >> dlat.hour = subwrd(loc,3)
> >> * prompt ' hour ' hour ' are read,'
> >> * say ' long=' dlong.hour ' lat=' dlat.hour
> >> ret = read(fname)
> >> rc = sublin(ret,1)
> >> endwhile
> >>
> >> if (rc!=2 & rc!=0)
> >> say 'File Error 5, rc=' rc
> >> return
> >> endif
> >>
> >> endhour = hour
> >> say ' endhour=' endhour
> >>
> >> * Plotting
> >>
> >> 'set line 'lcolor' 'lstyle' 'lthick
> >> 'query w2xy 'dlong.start' 'dlat.start
> >> xprev = subwrd(result,3)
> >> yprev = subwrd(result,6)
> >> 'draw mark 'marktype' 'xprev' 'yprev' 'marksize
> >> next = start+jump
> >> while (next <= endhour)
> >> * say ' 'dlong.start' 'dlat.start
> >> 'query w2xy 'dlong.next' 'dlat.next
> >> xnext = subwrd(result,3)
> >> ynext = subwrd(result,6)
> >> 'draw line 'xprev' 'yprev' 'xnext' 'ynext
> >> * say ' 'xprev' 'yprev' 'xnext' 'ynext
> >> 'draw mark 'marktype' 'xnext' 'ynext' 'marksize
> >> next = next+jump
> >> xprev = xnext
> >> yprev = ynext
> >> endwhile
> >>
> >> say fname ' is working fine.'
> >>
> >> * read in the filename to be plotted next
> >>
> >> say 'Enter File Name: (type q to stop)'
> >> pull fname
> >>
> >> endwhile
> >>
>
>
> *----------------------------------------------------------------------
> *
> * Adapted from plot_hurricane_center2c.gs, which was adapted from:
> *
> * (1) "plot_hurricane_center2[a][b].gs" (from "plot_hurricane_center.gs
> "),
> * locally modified versions derived from Joe Covert's script
> * "plot_tc_shi.gs" (Joe.Covert at noaa.gov), which was posted to the
> * GrADS Listserv on 9/13/2004 (his script was named plot_tc_shi.gs)
> * on 4/27/06, found via a Google search for "plot_tc_shi.gs":
> * http://caos.iisc.ernet.in/gslib/plot_tc_shi.gs
> *
> * (2) code in "hurricane_tracking.txt" (taken from an email exchange
> * posted to the GrADS Listserv by Kun-Hsuan Chou and
> * Arturo Caracas Uribe in Oct, 2004)
> *
> *
> * To use: grads -l
> *
> *----------------------------------------------------------------------
>
> function main()
>
> 'reinit'
>
> ************************************************************************
> * Allow external GrADS functions
> ************************************************************************
>
> rc = gsfallow("on")
>
> ************************************************************************
> * Define dataset file information and plotting limits for base map...
> ************************************************************************
>
> ** nc_file1 = ''
> ** nc_file2 = ''
> ** nc_file3 = ''
> ** nc_file = ''nc_file1' 'nc_file2' 'nc_file3''
> nc_file = 'your_netCDF_file'
>
> lon1 = 298 ; lon2 = 308
> lat1 = 20 ; lat2 = 25
>
> ************************************************************************
> * Legend captions, colors, and marks for the plots
> ************************************************************************
>
> ** nmodels = 1
> ** model.1 = 'isabel_ras'
> ** model.2 = 'isabel_isotke'
> ** model.3 = 'isabel_my25'
>
> ** titles.1 = model.1 ; colors.1 = 2 ; marks.1 = 2
> ** titles.2 = model.2 ; colors.2 = 3 ; marks.2 = 2
> ** titles.3 = model.3 ; colors.3 = 4 ; marks.3 = 2
> ***
> *** Define the legend plotter input...
> ***
> ** titles = '-t' ; colors = '-c' ; marks = '-m' ; lines = '-l'
> ** n=1
> ** while ( n <= nmodels )
> ** titles = ''titles' "'titles.n'"'
> ** colors = ''colors' 'colors.n
> ** marks = ''marks' "'marks.n'"'
> ** lines = ''lines' 1'
> ** n=n+1
> ** endwhile
>
> ** legend_info = ''colors' 'lines' 'marks' 'titles' -p'
>
> nmodels = 1
> model.1 = 'title_name_for_your_netCDF_dataset'
>
> titles.1 = model.1 ; colors.1 = 2 ; marks.1 = 2
> *
> * Define the legend plotter input...
> *
> titles = '-t' ; colors = '-c' ; marks = '-m' ; lines = '-l'
> n=1
> while ( n <= nmodels )
> titles = ''titles' "'titles.n'"'
> colors = ''colors' 'colors.n
> marks = ''marks' "'marks.n'"'
> lines = ''lines' 1'
> n=n+1
> endwhile
>
> legend_info = ''colors' 'lines' 'marks' 'titles' -p'
>
> * ...other drawing primitives
>
> marksize = 0.1
>
> lstyle = 1 ; lthick = 5
>
> ************************************************************************
> * Use "cbar_line" or "cbar_line_box"?
> ************************************************************************
>
> legend_plotter = 'cbar_line'
> * legend_plotter = 'cbar_line_box'
>
> ************************************************************************
> * Plot page limits
> ************************************************************************
>
> plot_vpage = '0 11 0 8.5'
> plot_area = '1 10 1 7.5'
>
> xl = subwrd(plot_area,1) ; xr = subwrd(plot_area,2)
> yb = subwrd(plot_area,3) ; yt = subwrd(plot_area,4)
>
> xc = xl + (xr-xl)/2
>
> ************************************************************************
> * GrADS metafile output...
> ************************************************************************
>
> 'enable print hurricane_track.gx'
>
> *-----------------------------------------------------------------------
> * Define and plot track of minimum surface pressure for each dataset...
> *-----------------------------------------------------------------------
>
> nf=1
> while ( nf <= nmodels )
>
> * Open dataset file and define parameters...
>
> fname = subwrd(nc_file,nf)
> 'sdfopen 'fname
> 'set dfile 'nf
> 'q file'
> rec3 = sublin(result,3) ; binary_file = subwrd(rec3,2)
> say
> say
> say '*** 'binary_file' ***'
> say
> rec5 = sublin(result,5)
> nx = subwrd(rec5,3) ; ny = subwrd(rec5,6) ; nz = subwrd(rec5,9) ; nt =
> subwrd(rec5,12)
>
> if( nf = 1 )
>
> * Plot base map...
>
> plot_base_map(plot_vpage,plot_area,lon1,lon2,lat1,lat2)
>
> endif
>
> * Define locations of "hurricane center" for plotting points, and write
> * locations out to ASCII text file for read-in for plotting track later...
>
> hurricane.nf = 'hurricane_'nf'.txt'
>
> ts=2
> tt=ts
> while ( tt <= nt )
> 'set t 'tt
> say
> say '---------'
> say ' tt = 'tt
> say '---------'
> say
> 'set lon 'lon1' 'lon2
> 'set lat 'lat1' 'lat2
> 'set z 1'
> *
> * here is where you put in the name of your sea-level pressure variable:
> *
> 'define psl = name_of_your_sea_level_pressure_variable'
> 'set gxout shaded'
> 'd psl'
> *
> * following interactive "box location" code adapted from "cbar_line_box.gs
> "...
> *
> say 'Click where you want the left upper corner of the box'
> 'query bpos'
> xb1o = subwrd(result,3)
> yb2o = subwrd(result,4)
> say 'Click where you want the right lower corner of the box'
> 'query bpos'
> xb2o = subwrd(result,3)
> yb1o = subwrd(result,4)
>
> say
> say '...left upper corner of the box at X Y: 'xb1o' 'yb2o
> say '...right lower corner of the box at X Y: 'xb2o' 'yb1o
> *
> * draw box to show specified area for defining hurricane center...
> *
> 'set line 1 1'
> 'draw rec 'xb1o' 'yb1o' 'xb2o' 'yb2o
> *
> * convert box "xy" coordinates to "grid" coordinates
> * for finding minimum "pressure" (hurricane center)...
> *
> 'q xy2gr 'xb1o' 'yb2o
> x1o = subwrd(result,3) ; x1 = math_int(x1o+0.5)
> y2o = subwrd(result,6) ; y2 = math_int(y2o+0.5)
> 'q xy2gr 'xb2o' 'yb1o
> x2o = subwrd(result,3) ; x2 = math_int(x2o+0.5)
> y1o = subwrd(result,6) ; y1 = math_int(y1o+0.5)
> say
> say 'Specified grid coordinates (x1o,x2o), (y1o,y2o) from box,'
> say 'rounded to (x1,x2), (y1,y2) for finding minimum "pressure"...'
> say
> say ' (x1o,x2o) = ('x1o','x2o') --> (x1,x2) = ('x1','x2')'
> say ' (y1o,y2o) = ('y1o','y2o') --> (y1,y2) = ('y1','y2')'
> *
> * find minimum "pressure" within box area (x1,x2), (y1,y2)...
> *
> 'set x 'x1
> 'set y 'y1
> 'set z 1'
> 'set t 'tt
> 'set gxout print'
> nxp = x2-x1+1
> * say ' nxp = 'nxp
> nyp = y2-y1+1
> * say ' nyp = 'nyp
> 'd minloc(min(psl,y='y1',y='y2'),x='x1',x='x2')'
> rec=sublin(result,nxp+3)
> xc=subwrd(rec,1)
> 'd minloc(min(psl,x='x1',x='x2'),y='y1',y='y2')'
> rec=sublin(result,nyp+3)
> yc=subwrd(rec,1)
> say
> say 'location of minimum "pressure"...'
> say
> say ' (xc,yc) = ('xc','yc')'
> *
> * find "world" coordinates of (xc,yc) and convert "world" coordinates
> * to "xy" coordinates for plotting track of hurricane center...
> *
> 'set x 'xc
> lonval = subwrd(result,4)
> 'set y 'yc
> latval = subwrd(result,4)
> say ' (lonval,latval) = ('lonval','latval')'
> 'q w2xy 'lonval' 'latval
> xpos = subwrd(result,3)
> ypos = subwrd(result,6)
> say ' (xpos,ypos) = ('xpos','ypos')'
> *
> * write (xpos,ypos) to output file...
> *
> res = write (''hurricane.nf'','t = 'tt' xpos = 'xpos' ypos = 'ypos'')
>
> pause()
> *
> * erase box showing area for defining hurricane center...
> *
> * 'set line 0 1'
> * 'draw rec 'xb1o' 'yb1o' 'xb2o' 'yb2o
> tt=tt+1
> endwhile
>
> res = close (''hurricane.nf'')
>
> nf=nf+1
> endwhile
>
> * Clear frame and re-plot base map...
>
> plot_base_map(plot_vpage,plot_area,lon1,lon2,lat1,lat2)
>
> * Plot track(s)...
>
> nf=1
> while ( nf <= nmodels )
>
> * Specify drawing primitives
>
> marktype = marks.nf
> lcolor = colors.nf
>
> say ' marktype, marksize, lcolor, lstyle and lthick:'
> say ' 'marktype ' ' marksize ' ' lcolor ' ' lstyle ' ' lthick
>
> tt=ts
> *
> * read (xpos,ypos) from ASCII text input file...
> *
> res = read(''hurricane.nf'') ; rc = sublin(res,1)
> if( rc != 0 )
> say '"read" status = 'rc
> exit
> endif
> rec = sublin(res,2) ; say '"hurricane.'nf'" record: 'rec
> xc = subwrd(rec,6) ; yc = subwrd(rec,9)
>
> 'set line 'lcolor' 'lstyle' 'lthick
> 'draw mark 'marktype' 'xc' 'yc' 'marksize
> tt = tt+1
> while ( tt <= nt )
> res = read(''hurricane.nf'') ; rc = sublin(res,1)
> if( rc != 0 )
> say '"read" status = 'rc
> exit
> endif
> rec = sublin(res,2) ; say '"hurricane.'nf'" record: 'rec
> xn = subwrd(rec,6) ; yn = subwrd(rec,9)
> say ' 'xc' 'yc' 'xn' 'yn
> 'draw line 'xc' 'yc' 'xn' 'yn
> 'draw mark 'marktype' 'xn' 'yn' 'marksize
> tt=tt+1
> xc = xn
> yc = yn
> endwhile
>
> nf=nf+1
> endwhile
>
> say
> say '...plot legend'
> ''legend_plotter' -x 3 -y 6 'legend_info
> say
>
> 'print'
> 'disable print'
>
> say
> say '************************************************'
> say ' Finished with this script.'
> say '************************************************'
> say
>
> return
>
> function plot_base_map(plot_vpage,plot_area,lon1,lon2,lat1,lat2)
>
> * Plots base map...
>
> 'c'
> 'set vpage 'plot_vpage
> 'set parea 'plot_area
> 'set lon 'lon1' 'lon2
> 'set lat 'lat1' 'lat2
> 'set mproj latlon'
> 'set mpt * 1 1 5'
> 'set mpdset hires'
> 'set poli on'
> * 'set grid on'
> 'set grads off'
> 'set gxout contour'
> 'draw map'
>
> * add lon/lat lines...
>
> 'set ccolor 1'
> 'set cstyle 5' ; 'd lon'
> 'set cstyle 5' ; 'd lat'
>
> * add title, x- and y-labels...
>
> 'draw title \\ Track of Minimum Surface Pressure'
> 'draw xlab Longitude \\'
> 'draw ylab \\ Latitude'
>
> return
>
> _______________________________________________
> gradsusr mailing list
> gradsusr at gradsusr.org
> http://gradsusr.org/mailman/listinfo/gradsusr
>
>
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