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I am using the bfastSpatial package in R. One of the parameters that I have to set is the QC_val=0x 'a number'. I do not understand what number I have to insert. I am using MOD11A2 product (MODIS LST 8-day product). I have read that QC values to KEEP in the data. But what I can not understand is what are the values. For example, the range of the values in the QC images that I use is [2-90].

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  • What function in that package needs that parameter? I can't see any mention of QC_val here: loicdutrieux.net/bfastSpatial
    – Spacedman
    Dec 13, 2018 at 10:42
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    The function cleanMODIS. Here is an example: MODISclean <- cleanMODIS(x=modis, data_SDS=1, QC_SDS=3, bit=TRUE, QC_val=0x19, fill = (32761:32767))
    – Dolby
    Dec 13, 2018 at 10:53
  • Have you read the help for that function? If so, what part of it do you not understand. Please edit your question.
    – Spacedman
    Dec 13, 2018 at 11:06
  • I have edited my question. I hope that now I have made my problem more clear.
    – Dolby
    Dec 13, 2018 at 11:15

1 Answer 1

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From documentation:

Numeric or vector of numerics. Quality control values to keep in the data. If bit is set to TRUE QC_val is a BYTE (hexadecimal or decimal) where each bit refers to a bit in the QC layer element (i.e.: bitpos = 0xA1 targets bits 7, 5 and 0 --- 1010 0001). When bits targetted by QC_val are activated, the corresponding observation in the data layer is filtered out.

Check product documentation to know which QA flag you need to preserve: https://lpdaac.usgs.gov/sites/default/files/public/product_documentation/mod11_user_guide.pdf

If you still don't know how to handle QA Flags, convert QA flags to layers and mask layers after: MOD09A1 QC layer

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