[ferret_users] poly_vectors on curvilinear grid

[jean li <xgeast@xxxxxxxxx>]

Hi all:

 

I am trying to use ploy_vectors to plot the vectors on curvilinear grid. It seems to me that my script is fine, but I couldn't get the plt_x_arrow, plt_y_arrow generated by poly_vectors.  I checked the variables that went into the poly_vectors, they are correct.

Maybe the subsampling of the u,v on curvilinear grid causes the problem? 

 

Thanks for your help.  

 

Jean

 

Below is my script:

use test.nc
show data

let lon_vec=lon[gx=water_u] + 0*lat[gy=water_u];
let lat_vec=0*lon[gx=water_u] + lat[gy=water_u];

let lon_vec_s=lon_vec[x=1:320:20,y=1:428:20];
let lat_vec_s=lat_vec[x=1:320:20,y=1:428:20];

let u_vec=water_u[l=1,x=1:320:20,y=1:428:20];
let v_vec=water_v[l=1,x=1:320:20,y=1:428:20];

set mem/size=500
go poly_vectors.jnl lon_vec_s lat_vec_s u_vec v_vec 8 "arrow"

let val=ysequence(u_vec);
polygon/over/nolabel/nokey/pal=green plt_x_arrow, plt_y_arrow, val

 

My data file look like:

 

    1> ./test.nc  (default)
 name     title                             I         J         K         L
 LON      longitude                        1:320     1:428     ...       ...
 LAT      latitude                         1:320     1:428     ...       ...
 WATER_U  Eastward Water Velocity          1:320     1:428     ...       1:240
 WATER_V  Northward Water Velocity         1:320     1:428     ...       1:240