Re: Variance and missing_value

[Steve Hankin <Steven.C.Hankin@xxxxxxxx>]

Hi Tony,

You haven't included the OPeNDAP URL, so I cannot test ... this is a guess.

It looks to me like in your dataset missing value points are represented as
zero's.  In the bottom figure (with white continents) the dataset documents
the missing value flag, either with the missing_value attribute or with the
_FillValue attribute.  In the top figure the missing value flag is
undocumented.

If my above guess is correct then to fix this problem you need only include
the command

    SET VARIABLE/BAD=0.0 <my_var_name>

prior to making the plot.  In the context of LAS such a command would normally
by included in the initialization script for the dataset.

I hope this helps.

    - steve

=============================================

Tony Jolibois wrote:

>           Hi ferreters,
>
> I have a problem ploting a variance on an opendap dataset. Please see
> the images attached.
> I don't understand why on one plot the land are purple (the minimum of
> the palette).
> Is it a problem with the missing_value of the netCDF ?
>
> Thanks in advance,
> Tony
>
> Ferret v5.5
> The dataset are in netcdf served by a grads-dods server.
>
>   ------------------------------------------------------------------------
>  [Image]  [Image]

--

Steve Hankin, NOAA/PMEL -- Steven.C.Hankin@noaa.gov
7600 Sand Point Way NE, Seattle, WA 98115-0070
ph. (206) 526-6080, FAX (206) 526-6744