Right when the rows really are independent, and the cleanest way to MEASURE what geography is worth: run it against spatial_cv() on the same points and the gap is the spatial optimism.
Arguments
- k
Number of folds.
- test_frac
Share held out as the test set, drawn first.
- group
"auto" keeps the rows of one profile_id together when the table repeats profiles; NULL or "row" makes each row its own unit; a column name, or a vector with one label per row, names the groups.
- seed
Seed for the partition only (see with_local_seed): a fixed plan reproduces even when the training seeds change.
- calibration_frac
Share of ALL the points held out as a calibration set for the intervals, carved after the test set by the same criterion; 0 for none. It trains nothing and chooses nothing: dsm_final() predicts it and calibrates its "split" interval there.