Merge pull request #16 from prakaa/data_dir

Add data dir explanation

README.md

@@ -45,7 +45,20 @@ Simply import `mms_monthly_cli` as follows:
 import mms_monthly_cli.mms_monthly as mms_monthly
 ```
 
-This will expose the following functions (accessed using `mms_monthly.<func_name>`):
+This will expose the functions listed below (accessed using `mms_monthly.<func_name>`).
+
+> [!NOTE]
+> The `data_dir` argument requires you to specify which folder within `MMSDM_YYYY_MM` you are interested in.
+> Most users will be interested in tables within `DATA` (i.e. `data_dir="DATA"`).
+>
+> You can also access `PREDISP_ALL_DATA` (pre-dispatch data)
+> and `P5MIN_ALL_DATA` (5-minute pre-dispatch data). Data tables in the `PREDISP_ALL_DATA` folders
+> contain *all* forecasts for an interval of interest, whereas `PREDISPATCH` data tables in the `DATA` folder only contain the latest interval
+> (refer to [this part of the NEMSEER docs for more detail](https://nemseer.readthedocs.io/en/latest/quick_start.html#predispatch-tables)).
+> It is unclear if the same is true for `P5MIN_ALL_DATA`; `P5MIN` data tables in `DATA` appear have the same data with some minor differences
+> (e.g. one column name is different in the constraint files).
+>
+> If you are accessing pre-dispatch data, consider using [NEMSEER](https://github.com/UNSW-CEEM/NEMSEER).
 
 ---
 ```python