pyflwdir.FlwdirRaster.upscale

FlwdirRaster.upscale(scale_factor: int, method: Literal['ihu', 'eam_plus', 'eam', 'dmm'] = 'ihu', uparea: ndarray | None = None, **kwargs) → tuple[FlwdirRaster, ndarray]

Upscale a flow-direction network to a lower resolution.

Available methods are Iterative Hydrography Upscaling (IHU) [2], Effective Area Method (EAM) [3] and Double Maximum Method (DMM) [4].

This method supports D8 and LDD flow-direction data only.

[2]

Eilander, D. et al (2021). A hydrography upscaling method for scale-invariant parametrization of distributed hydrological models. Hydrology and Earth System Sciences, 25(9), 5287–5313. https://doi.org/10.5194/hess-25-5287-2021

[3]

Yamazaki, D. et al (2008). An Improved Upscaling Method to Construct a Global River Map. Proceedings of the 4th Asia-Pacific Hydrology and Water Resources (APHW) Conference.

[4]

Olivera, F. et al (2002). Extracting low-resolution river networks from high-resolution digital elevation models. Water Resources Research, 38(11), 13-1-13–18. https://doi.org/10.1029/2001WR000726

Parameters:

• scale_factor (int) – Number of high-resolution cells along each side of an upscaled cell.

• method ({'ihu', 'eam_plus', 'eam', 'dmm'}) – Upscaling method, by default ‘ihu’.

• uparea (2D array of float or int, optional) – Raster of upstream area. Calculated on the fly if not provided.

• **kwargs (dict) – Additional keyword arguments passed to the selected upscaling method. For IHU, these include minlen_ratio, minupa_ratio, r_ratio, niter, opt_rivlen, min_error, and pit_out_of_cell.

Returns:

• flw (FlwdirRaster) – Upscaled flow-direction raster.

• idxs_out (2D array of int) – Linear indices of the high-resolution outlet cells corresponding to each upscaled cell.