# Grdvector in lon/time instead of lon/lat

Hi there,

The question is pretty much in the title. I have a NetCDF file containing wind vectors :

``````float u(time, latitude, longitude) ;
float v(time, latitude, longitude) ;
``````

But instead of plotting the arrows in lon-lat diagram, I’d like to plot them in lon-time.

The first step seems to be to average `v` for each time increment using grdfilter (`-Fm[...]` within my box of interest), then to plot it.

The question is how ? How do I achieve these two steps ?

Something like this :

Well, compute
`lon, lat, time, angle, length`

and plot -Sv but `length` must be in plot units

`lon, time, angle, length`

What do you mean ?

Something like

``````gmt grdvector \$file?u[lon,time] \$file?v[lon,time]
``````

?

No, I men `psxy -Sv .... -Rlon/time`

Hm, I’ll give it a shot. Thanks @Joaquim for the suggestion.