polytube woes

[Janet Sprintall <janet@xxxxxxxxxxxxx>]

Hi,
I  have a data set (eddy.cdf) that consists of a time series the 
latitude (alat1) and longitude (along1) for 39 eddies:

yes? sh data
    currently SET data sets:
   1> ./eddy.cdf  (default)
name     title                                                       
I         J         K         L
ALAT1    ALAT[G=MY_GRID]                  1:39      ...       ...       
1:200
ALONG1   ALONG[G=MY_GRID]            1:39      ...       ...       1:200

I can plot the time series of the change in latitude of the 39 eddies using:
>plot/nolab/i=1/line=1/vlim=-63:-55/t=15-nov-1992:18-mar-1998 alat1
>repeat/i=1:39 plot/nolab/line=1/over alat1

But now I would like to color the lines using longitude. I have been 
successful in getting the outLINE of the polygons to do this using:

>let dum = t[g=alat1]
>let mask = if alat1 then 1
>let dm=dum*mask
>go polytube 
polygon/over/vlimit=-63:-55/line/nolab/nokey/levels=(280,310,2)/fill 
dm[i=1] alat1[i=1] along1[i=1] 0.6
>repeat/i=1:39 (go polytube 
polygon/over/line/pal=terrestrial/noaxes/nolab/nokey/levels=(280,310,2)/fill 
dm alat1 along1 0.6; ppl shaset reset)

But very few of all the polygons are actually filled with the palette! 
In fact only the very first eddy has all the polygons filled 
(correctly!), the next two have a couple of boxes filled (also 
correctly), and the remainder consist of just the outlined polygons - 
the polygons are in the correct place, but they are not filled!

Can anyone help me to fill my polygons?

thanks!
Janet