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Is This Wheat Short of Water?

From texture features of a chlorophyll fluorescence image, how water-stressed is this wheat plant? Catching stress early lets a farmer water before yield is lost.

Use caseBiologyPredictionModel evaluation

The table

1,188 wheat images described by texture features from chlorophyll fluorescence, labelled by water-stress class. It's in Welt's research catalogue as Wheat Water Stress Texture Features, 1,188 rows by 23 columns, licensed CC0. The catalogue measures its signal at 0.30. At 1,188 rows and 22 features, TabICLv2, Kumo Tabular Medium and Mitra-v2 take the table as it is. The others can't take a table this size, so the walkthrough leaves them out.

Walkthrough

  1. Load it from the catalogue

    Find the table, read its recorded target and print the column names.

    import pandas as pd
    from welt import Client
    
    with Client() as client:
        item = client.research_datasets(q="wheat water stress texture", limit=1)["items"][0]
        info = client.research_dataset(item["id"])
        data = client.load_research_dataset(item["id"])
    
    target = info["targets"][0]
    target = target["name"] if isinstance(target, dict) else target
    print([column["name"] for column in info["schema"]], target)
  2. Pick the rows

    Set aside 20 rows to predict at the end, and keep the rest for the models to learn from.

    known = data.dropna(subset=[target])
    new_rows = known.sample(20, random_state=1)
    table = known.drop(new_rows.index)
  3. Compare the models and predict

    The models compete on the same folds against a simple guess, then the top-ranked one is fitted on the whole table. ROC AUC runs from 0.5, a coin toss, to 1, a perfect ranking, and a lower Brier score means the probabilities can be trusted more. The last table puts each prediction next to the real answer.

    with Client() as client:
        evaluation = client.evaluate(table, target, task="classification", seed=7,
                                     models=["tabicl-v2", "kumo-medium", "mitra-v2"])
        model = evaluation.fit()
    
    print(evaluation.summary()[["name", "rank", "roc_auc_mean", "brier_mean"]])
    features = new_rows.drop(columns=target)
    print(pd.DataFrame({"actual": new_rows[target].values, "predicted": model.predict(features),
                        "probability": model.predict_proba(features).max(axis=1)}))

What you get

A stress class per plantWith a probability for each level.
Earlier wateringSpot stress before it shows to the eye.
An honest signalThe catalogue measures a modest signal, so read the baseline comparison.

Try it

Use Open with to run the research datasets notebook in Colab, Kaggle or Jupyter and search for "wheat water stress texture", or run the code above after pip install "welt-client[parquet]".