geopfa.extrapolation.backfill_gdf_at_height

backfill_gdf_at_height(gdf, *, value_col, z_value, z_tol, X_grid, Y_grid, backfilled_array)[source]

Backfill missing values in a GeoDataFrame at a specific Z slice using a precomputed 2D grid of fill-in predictions.

Only rows whose z coordinate is within z_value ± z_tol and whose value_col is NaN will be filled. The fill values are obtained via nearest-neighbor lookup in the X-Y plane from the provided grid.

Parameters:

  • gdf (geopandas.GeoDataFrame) – Input GeoDataFrame containing numeric columns 'x', 'y', 'z', and the target value_col.

  • value_col (str) – Column name of the variable to fill.

  • z_value (float) – The Z slice to target.

  • z_tol (float) – Allowed absolute difference between a point’s z and z_value.

  • X_grid (numpy.ndarray) – 2-D array of X coordinates defining the grid.

  • Y_grid (numpy.ndarray) – 2-D array of Y coordinates defining the grid.

  • backfilled_array (numpy.ndarray) – 2-D array of predicted values corresponding to X_grid / Y_grid.

Returns:

geopandas.GeoDataFrame – A copy of the input GeoDataFrame where NaNs in value_col at the specified Z slice have been replaced with nearest-neighbor grid values.

Notes

  • Points outside the Z tolerance range are not modified.

  • Only NaN entries are filled; existing values are left unchanged.

  • Nearest-neighbor search is performed using scipy.spatial.cKDTree.

  • Grid shapes must match: X_grid.shape == Y_grid.shape == backfilled_array.shape.