shell scripts:

mvector.sh

Syntax

Eammple: Tides in the Skagerak

first copying the file userdef.ncl from /home/arnem/lib/ncl-metno/
then, specifying the title to
```
mytitle= "Skagerak circulation"
```

further, modifying the contents of four lines near the top to

x1= 50     ; Leftmost  grid point to depict, for dimension  x  or  lon
x2=150     ; Rightmost grid point to depict
y1= 45     ; Lowermost grid point to depict, for dimension  y  or  lat
y2=120     ; Uppermost grid point to depict

in order to zoom in

and modifying the vector specification further down to

vsz= 0.04   ; Size (length) of reference vector
vsp= 0.20   ; Speed         of reference vector
vd = 0.04   ; Distance between vectors
curly_on= 1 ; =1: Use curly vectors, otherwise, use standard vectors

Finally, the following command was issued:

mvector.sh 4d bio4km_uv.nc u v 1 1 43 -25

By executing this command, a set of ppm & gif images for time step no. 1 through 43 results. When the gif images assembled as an animation, the result is:

mvector.sh: syntax

mvector.sh --help

        mvector.sh  /  ncl-metno 1.2

>>>
>>>
>>> Syntax:
>>> =======
>>>
>>> NOTE: This script will provide a set of output files, where
>>>  the value of the final (3rd or 4th) dimension changes from
>>>  one output file to the next. Below, we assume that this
>>>  dimension is time.
>>>
>>> ...if  <option> is  4d  or  4dmap:
>>>  mvector.sh <option> <file> <u> <v> <depth> <first> <last> (<step>)
>>> ...if  <option> is  3d  or  3dmap:
>>>  mvector.sh <option> <file> <u> <v> <first> <last> (<step>)
>>> where
>>>    <option>    specifies dimensions and geo- or nongeo-grid
>>>                 implemented:
>>>                  [34]d    - [34]D fields
>>>                  [34]dmap - [34]D fields, dims. are lon & lat
>>>                  ...[34]dmap will be displayed on a geogr. map
>>>    <file>      name of the netcdf file
>>>    <u>         name of variable w/ velocity in the x-direction
>>>                 on the netcdf file (case sensitive)
>>>    <v>         name of variable w/ velocity in the y-direction
>>>                 on the netcdf file (case sensitive)
>>>    <depth>     vertical level no.
>>>    <first>     first time step no.
>>>    <last>      last  time step no.
>>>    <step>      time step between consequtive frames
>>>                 (optional, set to  1  if not specified by user)
>>>    <delay>     frame delay in ms (optional, set to  10  if not specified by user)
>>>
>>>  The script will produce a gif animation.
>>>
>>>
>>> User specifications:
>>> ====================
>>>
>>>  By copying the default spec.s from
>>> /home/arnem/lib/ncl-metno/userdef.ncl
>>>  to the directory where the command 'mvector.sh' is given,
>>>  the user may specify
>>>   * title
>>>   * font
>>>   * zooming
>>>   * vector spec.s (size, distance, curly/regular vectors)
>>>   * plot size limits
>>>   for geographical maps:
>>>   * names of longitude & latitude variables
>>>   * map projection
>>>   * coastline detail level
>>>   (look up, or copy, this file to edit your own 'userdef' file).
>>>
>>>
>>> Example:
>>> =========
>>>
>>>  mvector.sh 4dmap hydrography.nc u v 1 5 15 2
>>>    will produce vectors on a lon-lat grid w/ a map, of
>>>     the first vertical level and time steps no. 5, 7, 9, 11, 13 and 15,
>>>     based on variables 'u' and 'v' on the file 'hydrography.nc'
>>>
>>>
>>> Terminating.