Station mapping and wind vectors

[Tess Parker]

List - I am plotting the calculated geostrophic wind using station data. My
GrADS commands are as follows:

$  grads
ga-> open geomthstn.ctl
ga-> set xsize 750 550
ga->  set grads off
ga-> set mproj nps
ga-> set lon 0  360
ga-> set lat 70  90
ga-> set digsize 0.05
ga-> set dignum 2
ga-> set gxout vector
ga-> set arrlab on
ga-> d u;v
ga-> draw title Monthly Geostrophic Wind

The problem I have is that the scale arrow at the bottom of the plot, which
usually displays with gridded data from the 'set arrlab on' command, does
not appear on station mapping plots for some reason? This makes it hard to
see the scale of the vectors, as each plot is different.

Any help gratefully received.