SHAP values over space, time

[jds485]

We could display SHAP values as maps to accompany the data splits that we have (seasons, land covers, physio regions).

• Sum the SHAP values for all data for each reach
• Plot a map for each feature
• Maybe side by side with a map of the mean value of that feature
  This would reveal how features are used differently across the reach network

We could also display SHAP values over time, aggregated over reaches

• One SHAP timeseries for each feature
• Maybe also showing the feature value timeseries