Skipping barbs in GRADS

[Ioannis Koletsis]

Dear all,

I plot wind barbs using the maskout function. Each color corresponds to a different wind intensity (barbs), for example:

'set ccolor 9'
'd maskout(u*2,mag(u,v)-0;maskout(v*2,1.25-mag(u,v))'
'set ccolor 14'
'd maskout(u*2,mag(u,v)-1.26;maskout(v*2,3.75-mag(u,v))'
'set ccolor 4'
'd maskout(u*2,mag(u,v)-3.76;maskout(v*2,6.25-mag(u,v))'
e.t.c.

I would like to skip barbs in both x and y direction
 
I tried to use the skip function,  

'd skip(maskout(u*2,mag(u,v)-3.76;maskout(v*2,6.25-mag(u,v)),2,2)

but it didn't work!

Would somebody please help me? 
Any idea?

Thanks in advance

John


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Ioannis Koletsis
National Observatory of Athens
Institute for Environmental Research
Lofos Koufou
15236-Penteli
Athens-Greece
Tel: (+30) 210 8109140
e-mail: koletsis at meteo.noa.gr
           ikoletsis at gmail.com
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