The GRQA data package contains a main folder (GRQA) with a folder for data, metadata and figures.

The data folder contains the CSV files for processed observation data (*_GRQA.csv) along with corresponding metadata (observation site information, etc) for 42 different water quality parameters.

The meta folder contains the following files:
List of parameter codes in GRQA used for looping over during parallel processing (GRQA_param_codes.txt)
Potential duplicate observation sites per parameter (*_dup_obs.csv)
Basic statistics of GRQA observation time series per parameter (GRQA_param_stats.csv)

The following figures are included in the dataset for each parameter:
Map of spatial distribution of observation sites per source dataset (*_spatial_dist.png)
Map of monthly availability of time series per site (*_availability.png)
Map of monthly continuity of time series per site (*_continuity.png)
Map of median observation values per site (*_median.png)
Temporal distribution plot of observations per source dataset (*_temporal_hist.png)
Histogram of observation values per source dataset (*_hist.png)
Box plot of observation values per source dataset (*_box.png)

Additional grid plots (GRQA_*_grid.png) of each of the aforementioned seven plot types showing DO, DOC, TP and TSS were created to be included in the scientific paper describing GRQA.

In addition, there is a folder for each of the five source datasets (CESI, GEMSTAT, GLORICH, WATERBASE and WQP) containing metadata and statistics collected from both raw and processed data.

The raw/meta folder contains the following files:
Lookup tables used for harmonizing the parameters and units (*_code_map.csv, WQP_code_map.txt)
Unit files for sources with multiple units per parameter (*_units.csv)
Remark code lookup for GLORICH (GLORICH_remark_codes.csv)
US state codes used for downloading WQP temperature data (fips_state.csv)

The processed/meta folder contains the following files:
Number of missing values in source file columns (*_missing_values.csv)
Source file size and row count information (*_file_info.csv)
Observation data statistics per parameter before harmonization (*_raw_stats.csv)
Observation data statistics per parameter after harmonization (*_processed_stats.csv)
Duplicate site IDs in source data (*_dup_sites.csv)

Scripts used for the creation of GRQA are found at the GitHub page of the Landscape Geoinformatics Lab of University of Tartu: https://github.com/LandscapeGeoinformatics/GRQA_src