Is
QC
Screening Dashboard for Precipitation Stable Isotope Records
Preview (first 10 rows)

Station Data Availability Over Time

Introduction

IsoQC is an interactive quality‑control dashboard designed for analysing stable isotope records (δ¹⁸O and δ²H) from precipitation samples.
The app helps users:

  • upload and inspect their own datasets,
  • visualise temporal availability,
  • compare a station’s measurements with nearby stations,
  • identify potential outliers based on thresholds,
  • export time‑series diagnostics.

This guide walks you through the complete usage of the application.

1. Uploading Your Data

Supported file types

You may upload the following:

  • Excel files: .xlsx, .xls
  • CSV files: .csv
  • Maximum file size: 500 MB

Required columns

Your uploaded dataset must contain:

  • Station – station name or code
  • Date – observation date (DD/MM/YYYY, YYYY-MM-DD, etc.)
  • Latitude – decimal degrees
  • Longitude – decimal degrees
  • Altitude – metres above sea level
  • δ¹⁸O (‰)
  • δ²H (‰)

Additional rules

  • If using Excel, ensure that the Date column has proper date formatting.
  • For CSV, you may manually specify:
    • delimiter (comma / semicolon / tab),
    • date format (any lubridate-compatible format, e.g. %d/%m/%Y).
  • Rows with both δ¹⁸O and δ²H missing are automatically removed.
  • The first row must contain column names only (no multi‑header files).

2. Column Mapping

After uploading, the app requests you to map the correct columns:

  • Station name
  • Altitude
  • Latitude
  • Longitude
  • Date
  • δ¹⁸O
  • δ²H

Once completed, click “Upload Data” to load your dataset into IsoQC.

A built‑in test dataset is also available via the Use Slovenian test dataset from Hatvani et al. (2025) button.

3. Data Preview and Availability

Dataset preview

The app displays:

  • a raw preview (first rows of your file),
  • a mapped preview (only the required and selected columns).

Station availability plot

You can visualise how many stations have data in a given period at:

  • Daily resolution
  • Monthly resolution
  • Yearly resolution

This helps identify data gaps and temporal coverage issues.

4. Using the Dashboard

Once your dataset is imported, the Dashboard tab activates the core functionality.

4.1 Station selection

Choose a station from the searchable dropdown.
The app will automatically:

  • focus the map on the selected station,
  • refresh the date range bounds,
  • update all plots.

4.2 Nearby stations and thresholds

You can customise:

  • Search radius (km) for selecting nearby stations
  • Thresholds for:
    • δ¹⁸O
    • δ²H
    • D‑excess
  • Elevation‑correction parameters (default: Kern et al. 2020)

Nearby stations appear on the map:

  • Blue → selected station
  • Dark grey → nearby stations within radius
  • Light grey → other stations
  • Black lines show station–neighbour distances.

5. Date Range Handling

IsoQC includes an advanced date‑range controller:

  • A slider for fast interval selection
  • Direct From / To date inputs
  • A Reset date range button
  • Station‑specific date limits
  • Smooth interaction: recalculation happens only after final slider release

If data are unavailable in the chosen interval, the app warns you (e.g., no δ¹⁸O or no δ²H).

6. Time-Series Plots

IsoQC provides multiple diagnostic plots, including:

δ¹⁸O corrected

δ²H corrected

D‑excess

δ²H vs. δ¹⁸O (XY plot)

For each variable:

  • The selected station is shown in colour.
  • Nearby stations appear in grey.
  • The nearby average appears as a black dashed line.
  • Difference bars use an interpretative colour scheme:
    • Light grey → below threshold
    • Dark grey → below threshold but above 2×SD
    • Purple → above threshold
    • Purple with black outline → strongly suspicious (above threshold & above 2×SD)

The XY plot distinguishes:

  • All points
  • Points under thresholds
  • Points above thresholds

7. Exporting Time-Series Data

Use the Download mean time series button to export a .csv containing:

  • Selected station values
  • Nearby mean values
  • Differences
  • Date range metadata
  • Thresholds
  • Elevation correction parameters
  • Search radius

The export includes UTF‑8 encoding with BOM for Excel compatibility.

8. Filling Missing Months (Optional)

If the dataset contains gaps for a specific month, you may:

  1. Insert a dummy numeric value for that month in your original file.
  2. Upload the updated file again.

IsoQC will compute an average for that month, which can be used as an estimated replacement.

9. Data Privacy Notice

IsoQC does not store user-uploaded datasets. Uploaded files are processed only for the active session and are released when the session ends.

To support operation, troubleshooting, security, and basic usage statistics, IsoQC stores a limited set of technical usage logs in an internal SQLite database. These may include:

  • session start and end time,
  • session duration,
  • active tab,
  • app version,
  • session token,
  • limited technical event details,
  • the country associated with the session.

IsoQC does not store the exact IP address in its SQLite usage log.

The country value is determined at session start from network information. In the current implementation, the browser contacts a geolocation service (ipapi.co) to obtain the country value. The returned country may be stored in the app log, while the exact IP address is used only transiently for the lookup and is not stored by IsoQC in the SQLite database.

These limited logs are used only for:

  • secure and reliable operation of the app,
  • troubleshooting and maintenance,
  • basic aggregated usage statistics.

For general information about HUN-REN CSFK website data processing, please see the institutional Privacy Notice: [HUN-REN CSFK Website Privacy Notice]

Need help?

If you encounter any unexpected behaviour, refer to:

Thank you for using IsoQC!