Why NDR model generate streams bigger than routedem?

[MayJi]

I wonder why the stream from Route dem is different from the stream of NDR. Or I did something wrong.
I use TFA 3000 for both models.

Please suggestions
Regards,
May

[esoth]

Hi @MayJi,
Your file is called stream_mask_D8_up.tif, so I assume you selected the D8 routing algorithm for RouteDEM. NDR uses the MFD algorithm, so they will produce different results.

If you select the MFD algorithm in RouteDEM, it should produce the same result as NDR. They use the same underlying pygeoprocessing algorithms to (1) fill pits in the DEM, (2) calculate flow direction from the filled DEM, (3) calculate flow accumulation from the flow direction raster, and (4) extract streams from the flow accumulation raster, given the TFA value.

[MayJi]

@esoth, thank you for your explanation. I got it now.
May