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Filling missing Value.

Added by Pugazenthi K 2 months ago

Hi everybody!
I have common doubt on cdo arithmetic operators.

While performing any one of the arithmetic operation for any two files, If one file has some missing timestep, then how it is filled??

For this I have just gone through cdo Github page https://github.com/AZed/cdo/blob/master/src/Arith.c,
There i was able fine some lines related to filling missing value for timestep, Variable and some other thing (Sorry iam not good at C) and concluded that it is filling from the first time step.

That is for Version 1.6.8 and Is there any up-gradation in filling value of missing timestep by any other method like averaging whole timestep or from mean of nearby timesteps ?
or else the refered git code itself doing the different job and i had interrupted wrongly

Thanks in advance and also sorry if this question is non reasonable.


Replies (5)

RE: Filling missing Value. - Added by Pugazenthi K 2 months ago

Sorry friends,
I have posted without compete surfing,
I have found recent version Arith.c in the repository directory, and found some advancements.
But I am still confusion in filling missing value and how it is filled.

Somebody kindly give some clarity or any documentation.

RE: Filling missing Value. - Added by Uwe Schulzweida 2 months ago

The filling in Arith is very simple. If infile1 has N steps and infile2 has only one step, all steps in infile1 will be arithmetically processed with the data of infile2. Arith has other filling modes, but in principle they work in the same way.

RE: Filling missing Value. - Added by Pugazenthi K 2 months ago

Simple nice explanation.
Is it possible to improve the filling technique with some additional options like taking averaging of preceding and succeeding lead times (which would be better for continuous variable in daily timescale) instead of copying previous year.
May be provided with options like 1 and 2 or may be as arguments.

Thanks @Uwe Schulzweida for quick response.

RE: Filling missing Value. - Added by Uwe Schulzweida about 2 months ago

From my point of view, the complexity limit has been reached in Arith.cc. But you are of course welcome to try to implement your ideas.
If I have understood you correctly, you want to fill in missing time steps depending on the preceding and succeeding time steps.
This seems to me to be technically similar to temporal interpolation. In this case, I would rather adapt Inttime.cc to your needs.

RE: Filling missing Value. - Added by Pugazenthi K about 2 months ago

Thanks for the greetings!
Yes, my idea is more or less same as time interpolation. But with little more option.
I will try to understand more about that and get back.

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