[GRASS-user] r.hants -how to determine frequency

[Rajat Nayak]

Dear All,

I'm trying to reconstruct a cloud free NDVI time series using r.hants
module in GRASS.
I have a total of 318 files covering a period of 14 years (Feb 2000 - Dec
2013).
I would like to know if there is any quantitative test to set the frequency
for this data range.

I used frequency values 4, with base period as 14, and frequencies of 28,
42 and 56 without any value for base period. Other parameters set were,
high and low suppression flag, invalid data rejection range (-0.2 and 0.9),
Fit error tolerance of 0.05, and degree of over determinedness
as 155.

However, none of the curves obtained match the expected distribution. (in
the study area there is cloud cover for 4 continuous months ).

I would be grateful if anyone can help me in fitting a right curve using
the right parameters.

Thank you in advance.

Regards

Rajat Nayak
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