pyflwdir.FlwdirRaster.upscale

FlwdirRaster.upscale(scale_factor, method='ihu', uparea=None, **kwargs)

Upscale flow direction network to lower resolution. Available methods are Iterative hydrography upscaling method (IHU) [2], Effective Area Method (EAM) [3] and Double Maximum Method (DMM) [4].

Note: This method only works for D8 or LDD flow directon data.

[2]

Eilander et al. in preperation (TODO update ref)

[3]

Yamazaki D, Masutomi Y, Oki T and Kanae S 2008 “An Improved Upscaling Method to Construct a Global River Map” APHW

[4]

Olivera F, Lear M S, Famiglietti J S and Asante K 2002 “Extracting low-resolution river networks from high-resolution digital elevation models” Water Resour. Res. 38 13-1-13-8 Online: https://doi.org/10.1029/2001WR000726

Parameters:

• scale_factor (int) – number gridcells in resulting upscaled gridcell

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

• uparea (2D array of int, optional) – 2D raster with upstream area, by default None; calculated on the fly.

• uparea – 2D raster with basin IDs, by default None. If provided it is used as an additional constrain to the IHU method to increase the upscaling speed.

Returns:

• flw (FlwdirRaster) – upscaled Flow Direction Raster

• idxs_out (2D array of int) – linear indices of subgrid outlets