[gradsusr] datawarn off suppresses plotting of constant field with holes

[Becker, Bernd]

Hello,

I wonder if this is a bug or a feature:

I define some blotch on a map, where it is hot
var=tmax
thresh=28
'define diff= 'var'.7(t='tim')-'var'.8(t='tim')'
'define hot= const(maskout(diff,diff-'thresh'),1)'

In winter, hot is undefined and I get 
"Blah blah undefined values" plotted on my map. 

I would like to not know about this, when it happens and accept 
no blotch is plotted. I am told, 
'set datwarn off'
 suppresses the message being printed to screen. Great!

but I note also, that using GrADS Version 2.0.a8.oga.1
'set datawarn off'
'd hot'  is not plotted at all if hot contains undefined values. 


set datawarn on
ga-> d hot
Constant field.  Value = 1
ga->         

fine, blotch plotted

set datwarn off : no blotch.

set datwarn on and blotch entirely undefined: no blotch plus message to
screen 

I suspect something not quite working with the logic of datawarn on or
off. 

Enjoy the weekend,
Bernd.

                  
--
Bernd Becker   Climate Impacts Product Development
Met Office Hadley Centre    FitzRoy Road  Exeter   Devon EX1 3PB  United
Kingdom
Tel.: +44 (0) 1392 884511 Fax: +44 (0)870 900 5050
E-mail:bernd.becker at metoffice.gov.uk -
http://www.metoffice.gov.uk/research/our-scientists/seasonal-to-decadal/
bernd-becker