Re: getting started finally

Hi Joe,

The "ncl_ncarg-5.2.1.MacOS_10.6_i386_64bit_nodap_gcc421.tar.gz" file you downloaded contains two major software packages: NCL and NCAR Graphics.

To use NCAR Graphics, one must either write a C or Fortran NCAR Graphics program and compile using a Fortran or C compiler. That's what the "ncargex cpex08" example is doing: copying an NCAR Graphics program to your local directory and trying to compile and execute it.

To use NCL, you don't need to compile anything. NCL is a "scripted" or "interpreted" language like python, which means in order to "run" your NCL script (also called "program"), you run the "ncl" interpreter on it from the UNIX command line. So, for example, if your NCL script that you included below is called "myscript.ncl", then you would run it on the UNIX command line with:

    ncl myscript.ncl

You have the graphical output going to a PS file called "old_out_xy.ps", so if your program finishes successfully, you should end up with a file by that name in your current directory.

For beginner information on using NCL, please see our getting started guide:

http://www.ncl.ucar.edu/get_started.shtml

Good luck,

--Mary

On May 22, 2011, at 5:36 PM, Joseph Cain wrote:

> So far I have failed to comprehend how to get any program going much less how to use NCL, so I thought I would ask a simple question having installed it on my IMac.
>
> I have tried using your examples like "ncargex cpex08"
> but after flailing around some it says
> The compile and link failed.
>
> At this time I have for example in my own directory
>
> [Joe-Mac-1008:~] josephcain% more .cshrc
> setenv NCARG_ROOT /applications/ncl_ncarg-5.2.1.MacOS_10.6_i386_64bit_nodap_gcc421
> setenv PATH /usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/texbin:/usr/X11/bin:/applications/ncl_ncarg-5.2.1.MacOS_10.6_i386_64bit_nodap_gcc421/bin
>
> I recall invoking the test code after the install, which I don't seem to be able to locate again, but it did produce a plot.
>
> I have the nice test program which Mary Haley wrote for me not long ago which I thought I would use as a test to get started and try to understand some of the constructs.
>
> It is below, and an extract of the file "old_out" follows. My questions to help me understand how to get it going include:
>
> 1. Should the three load lines below be modified in some way ? If so or not, how are they supposed to be used?
> 2. afterwards, how does one compile and execute the code between the begin and end below? It is not obvious in any of the material I have read.
>
>
>
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
>
> begin
> ;---Read 7 columns of data, and ignore first line.
> data = readAsciiTable("old_out", 7, "float", 1)
>
> year = data(:,0)
> dlat = data(:,1)
> dlon = data(:,2)
> alt = data(:,3)
> X = data(:,4)
> Y = data(:,5)
> Z = data(:,6)
>
> ;---Start the graphics.
> wks = gsn_open_wks ("ps", "old_out_xy")
>
> ;---Set some plot options
> res = True
> res@gsnMaximize = True ; Maximize plot in frame
> res@gsnDraw = False ; Don't draw plot
> res@gsnFrame = False ; Don't advance page
>
> res@vpWidthF = 0.8 ; Change aspect ratio
> res@vpHeightF = 0.2 ; of plot
>
> plotx = gsn_csm_xy(wks, dlat, X, res)
> ploty = gsn_csm_xy(wks, dlat, Y, res)
> plotz = gsn_csm_xy(wks, dlat, Z, res)
> plotalt = gsn_csm_xy(wks, dlat, alt, res)
>
> ;---Panel all three plots on one page as 4 rows, 1 column
> pres = True
> pres@gsnMaximize = True
> pres@txString = "Comparison between X, Y, Z, alt"
> gsn_panel(wks,(/plotx,ploty,plotz,plotalt/),(/4,1/),pres)
>
> end
> --------------
>
> [Joe-Mac-1008:projects/mars/plots] josephcain% ls
> old_out old_out_xy.ncl old_out_xy.ncl copy
> [Joe-Mac-1008:projects/mars/plots] josephcain% head old_out
> yr dlat dlon alt X Y Z
> 1999.0396 -77.4576 236.5607 196.1897 37.5075 -70.3262 -8.0432
> 1999.0396 -76.7379 235.7316 191.3689 38.1892 -82.7721 1.8762
> 1999.0396 -76.0140 234.9799 186.6699 37.1596 -92.6662 13.3272
> 1999.0396 -75.2865 234.2944 182.0940 41.3300 -101.3463 25.5609
> 1999.0396 -74.5554 233.6664 177.6428 49.4288 -104.8782 45.9377
> 1999.0396 -73.8211 233.0883 173.3159 60.1135 -99.3531 83.4698
> 1999.0396 -73.0837 232.5538 169.1160 59.3724 -75.3881 143.5756
> 1999.0396 -72.3436 232.0578 165.0432 37.8042 -25.8652 213.3564
> 1999.0396 -71.6007 231.5958 161.0989 7.6971 58.0769 251.1240
> [Joe-Mac-1008:projects/mars/plots] josephcain% tail old_out
> 1999.0396 -26.1934 221.1180 177.4133 72.2601 -154.9218 -123.6529
> 1999.0396 -25.8164 221.0692 179.6584 91.7922 -150.4562 -108.3534
> 1999.0396 -25.4399 221.0206 181.9377 103.3611 -140.1341 -90.3866
> 1999.0396 -25.0639 220.9722 184.2483 125.7770 -131.1891 -57.8323
> 1999.0396 -24.6883 220.9239 186.5920 127.5109 -118.4844 -48.5433
> 1999.0396 -24.3131 220.8758 188.9685 123.6467 -104.1106 -40.9750
> 1999.0396 -23.9385 220.8279 191.3767 126.3278 -94.2096 -36.4291
> 1999.0396 -23.5643 220.7801 193.8179 128.2590 -86.2677 -32.3723
> 1999.0396 -23.1906 220.7325 196.2905 120.9526 -74.2833 -28.5982
> 1999.0396 -22.8174 220.6851 198.7957 115.4841 -67.6852 -22.9296
> [Joe-Mac-1008:projects/mars/plots] josephcain%
>

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Received on Mon May 23 08:58:24 2011