Missing Values

[Steve Cocks <scocks@xxxxxxxxxxxxxxxxxx>]

Howdy,   again,


I have run into a problem working with data having missing values.  For
instance, I was working with a block of 656 gridpts having u and v wind
components of data; out of this block there were 112 gridpts coded with
missing values.  I then compute the divergence from the same u and v
components and write the data to *.nc file.  Lo and behold, now I have
256 missing values, over twice as many.  I checked the u and v
components and whenever a u comp has a missing value, the v comp does
too and vice-versa.

My questions are:

1)  What is ferret doing to produce the extra missing values?

2)  In the future to track this problem, how can I get ferret to plot
the missing value points on a horizontal map? (Tried
"fill/pal=grey/level(-1.0E+34)/nolab variable"  and it didn't work)

3)  Whenever the shade or fill command is given for a variable does:

     a) Ferret ignor the missing value and plots an average of the
nearest neighbors to the missing value?
     b)  Ferret  not plot the value at all unless told to?



Thanks in advance

Scocks
Dept of Amos Sciences
Texas A&M University