[gradsusr] Help on Areal average using Grads

[Anil Kumar]

Hi Grad Users,

 

I have NetCDF file having Ocean Current Data (attached for reference). Am using below command to display u_velocity and v_velocity and generating vector plot using SKIP() function from Grads.

 

reinit

sdfopen D:/rtofs_glo_2ds_f024_daily_prog.nc <http://rtofs_glo_2ds_f024_daily_prog.nc> 

set vpage 0 11 0 8.5

set parea 0 11 0 8.5

set lon 74 434

set lat -70 70

set mproj latlon

set display color white

set datawarn off

set grads off

set timelab off

set xlab off

set ylab off

set frame off

set t 1

set cint 40

set display color white

set background 0 

set gxout vector

set cthick 6

set ccolor 1

d skip(u_velocity*1.95,8,8);skip(v_velocity*1.95,8,8)

printim D:\output.png x1061 y587 -t 0

 

output is attached and unfortunately this is not what i need exactly. It is just plotting every 8th point. I want to plot areal average of every 8 points and want exactly the same plot.

 


​

 

NetCDF file has 4320 LON points  and 2160  LAT points. The “display” command is powerful enough to iterate along the longitude and latitude. But aave() <http://www.iges.org/grads/gadoc/gradfuncaave.html>  function needs fixed X and Y dimensions, no STRIDE option for X and Y. 

 

How can I achieve this using Grads??? Ultimately I need global vector output.

 

Please help me on this. Thanks in advance.

 

-Anil Kumar

 

 

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