skipping negative values in GRADS

[Douglas Clark]

Sachin,

You may be able to use the maskout function (see GrADS documentation).

e.g. d maskout(field1,field1)
will only display values where field1>=0. Can also be used when defining a new variable.

You can choose to include some negative values by using an offset, eg
d maskout(field1,field1+10)

If your "bad" data lie outside the range of all "good" data, them maskout should be easy enough, otherwise you may have to do a bit more work (e.g. to maskout a range of values).

Doug



>>> sachinghude at TROPMET.RES.IN 26/03/2007 10:10 >>>

some technical problem occurred while sending this mail. Therefore, i am repeating the same mail.
If you have already received this mail, excuse me for repetition.
Dear All,
I have 5-years of monthly data in nc formate. The values ranges from -999 to 500 unit. -999 is undef however, there are also some negative values in between -999 and 0. I gathered that values below 0 is because of some retrieval error. when I looked into the data I found that these negative vales dosen't appear regularly for every month/year for the same gird point.  While taking (1)area average, (2)plotting time series and (3) plotting climatological mean for a particular geographical location I want to skip these negative values for all of the above calculation.
Would somebody please tell me what to do next as i do not have a much skill in grads.
Sachin D Ghude


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