hydromt_sfincs.workflows.downscaling.adjust_zsmax_dilation#

hydromt_sfincs.workflows.downscaling.adjust_zsmax_dilation(zsmax: UgridDataArray | DataArray, factor: float) → UgridDataArray | DataArray[source]#

Cell-space WSE dilation pre-step — works on both quadtree and regular grids.

For each already-wet cell/pixel, raise its zsmax to the max of (own, wet-neighbour values) within a radius of (0.5 + factor) cell widths. Dry cells stay dry — the wet-cell set is preserved (key safeguard: no new cells are flooded).

Typical use is to close 1 m-DEM connectivity gaps behind coarse-cell levees, where the parent cell’s single WSE sits below the levee crest on the fine DEM. Expanding each cell’s WSE plateau by a modest fraction of its own size lets the flood cross the crest continuously without introducing new wet cells elsewhere.

Parameters:

zsmax (xu.UgridDataArray or xr.DataArray) – Maximum water level (m). NaN where dry. Quadtree grids are dispatched to a cKDTree-based implementation on the cell centres; regular grids to a scipy.ndimage.maximum_filter with a disk footprint in pixel units.
factor (float) – Fraction of cell size. factor=0 picks up only the cell itself on a uniform grid; factor=0.5 reaches the 4 edge-neighbours; factor=1.0 reaches ~1.5 cell widths (full 3×3 stencil on a uniform grid). Must be >= 0. Returned unchanged when factor <= 0.

Returns:

Dilated zsmax on the same grid and with the same wet-cell set as the input. dilated >= zsmax on every wet cell.

Return type:

xu.UgridDataArray or xr.DataArray