Workflow/Quality-control.md

-Coming soon
+**ICOADS quality control indicator**
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+-----------------------------------
+- The `irf` variable stands for intermediate reject flag. A value of 2 indicates
+ that the report lacks suitable quality. This data is rejected from the ship [data
+ selection](Workflow/data-selection) in [split_by_type.R](https://git.noc.ac.uk/brecinosrivas/icoads-r-hostace/-/blob/master/rscripts/split_by_type.R) 
+
+- Deck priority assinged in [`add_dck_priority.R `](https://git.noc.ac.uk/brecinosrivas/icoads-r-hostace/-/blob/master/rutils/add_dck_priority.R): 
+
+    A certain priority is assign to some decks which are known to have a good quality data. The data expected to be of best quality is assigned a priority of 1, data with larger priority numbers will be flagged as the worst duplicate if identified as potential matches. These priority values are based on those from ICOADS (see https://icoads.noaa.gov/edoc/other/ for details)
+
+**Met Office climatological check**
+----------------------------------
+A precision criteria on selected variables is used to perform a 
+climatological quality control on the data.
+ 
+The precision criteria for each key variable per DCK,
+year and/or SID can be found in the following [file]()  (**Needs adding a link to the prec_file**)
+
+Having a precision criteria not only leads to a quality control of the climatological data stored on each report but helps to set tolerances when comparing variables from suspected duplicates. 
+
+A comparison of climatological variables allows for a match between reports in the duplicate identification procedure.
+
+**Needs liking to a script**
+
+**Met Office track check**
+-----------------------------------
+
+Several DCK have IDs that indicate a logbook, sheet or other block of data, that can be linked together to form ship tracks. 
+
+Before these reports can be linked, ID's need to be [pre-process](Workflow/processing-of-ids), to allow joins between records with similar supplemental ship names that can form plausible ship tracks using the Met Office Quality Control tracking scheme (MOQC track check from [IMMA](https://git.noc.ac.uk/brecinosrivas/icoads-r-hostace/-/wikis/How-to-install#install-dependencies-with-conda-all-platforms))
+
+The linked IDs are then checked using the MOQC track check, and for time duplicates. Reports that fail the track check are flag as the worst duplicate. Where positions (lat, lon) are similar the best duplicate is select by dck priority and number of quality variables as explained in previous sections.
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