[gradsusr] Ploting Cross/X at specific grid box

[Dan Zhang]

Dear James,

thanks a lot for your scripts and descriptions. It's great and I 
appreciate it a lot.
have a nice day!

Dan
> Dan:
>
> You can do this with two loops, one over X (lon) and the other over Y
> (lat).
> First open the data and plot something in order to plot scaling dimensions
> (if you don't want to display anything just set the maximum clev
> appropriately).
> Next, loop over all lat/lon and "set X" / "set Y" each step of the way,
> store the
> result in two variables.  Then, display your variable, and if equal to a
> valid
> point, draw a character.
>
> As an example, let's say you have a variable called "temp", with 360
> longitudes
> and 180 latitudes, with missing values equal to -999.
> *--------
> * open data set and display some variable
> 'sdfopen dansdata.nc'
> 'set cmax -10000'
> 'd temp'
>
> * loop over all lon/lat
> i = 1
> while ( i<= 360 )
>      j = 1
>      while ( j<= 180 )
> *  set location to (i,j) and store lon/lat response
>        'set x 'i
>        xlon = subwrd(result,4)
>        'set y 'j
>        ylat = subwrd(result,4)
> *  convert lon/lat to inches on the page
>        'q w2xy 'xlon' 'ylat
>        x1 = subwrd(result,3)
>        y1 = subwrd(result,6)
> *  display variable at this (i,j) point
>        'd temp'
>        val = subwrd(result,4)
> *  if value is not "missing", draw an "X" centered in the grid box
>        if ( val != -999 )
>           'set string 2 c'
>           'draw string 'x1' 'y1' X'
>        endif
>        j = j + 1
>      endwhile
>      i = i + 1
> endwhile
> *------
>
> Jim
>
>
>
> On 8/4/11 11:14 PM, Dan Zhang wrote:
>> Dear all,
>>
>> I have a global NetCDF file (resolution T31) with constant value of 1 and 1000
>> missing values. I would like to plot a cross/X at each grid box, except the
>> box with missing value.
>>
>> Questions:
>> Is it possible to do it by a loop of 'draw string x-position y-position X'?
>> Since x-position and y-position are related to the latitudes and longitudes
>> of  the boxes. But then how to exclude the boxes with missing value?
>> Or is there another easier way?
>>
>> Please help me out. Thanks a lot.
>> sincerely,
>>
>> Dan
>>
>>
>> ----------------------------------------------------------------------------------------------
>> Dan ZHANG
>>
>> Max Planck Institute for Meteorology
>> Meteorological Insititute, University Hamburg
>> KlimaCampus
>> Room 407, Grindelberg 5
>> D-20144, Hamburg
>> Germany
>>
>> Tel(office):+49 (0)40 42838 5067
>> Fax:+49 (0)40 42838 5066
>>
>> ----------------------------------------------------------------------------------------------
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-- 
---------------------------------------------------
Dan Zhang
Max Planck Institute for Meteorology;KlimaCampus, University Hamburg
Room 407,Grindelberg 5
Hamburg,Germany
Tel: 040 42838 5067
Email:zhangdan_49 at hotmail.com