Descontinuidade de drenagem no ArcGIS 10.6

Question

Estou usando o ArcGIS 10.6.1 para delinear a rede de drenagem a partir do DEM SRTM de 30 metros. Usei a ferramenta ArcHydro para isso. Percebi que há uma descontinuidade na rede de drenagem ao usar a projeção UTM, mas a drenagem contínua foi gerada na projeção GCS com os mesmos dados DEM.<\/P> A transformação de projeção pode deslocar o raster, mas como pode alterar o valor do pixel? Por favor, me informe se isso é um bug da versão 10.6.1, pois não enfrentei esses problemas na versão 9.x.<\/P> Obrigado.<\/P>

DeanDjokic · Answer

Process of "projecting" (really resampling) DEM can introduce "sinks" into the elevation model.  That would explain the discontinuities you are seeing.  Make sure you fill sinks in the projected DEM before running flow direction and flow accumulation functions.

RupeshSinha · Answer

Thankyou for your reply, I have reproject the dem using both (Bilinear and Cubic) resampling method but still I am getting discontinuous river network.

See the above image where Red line showing the river extracted from GCS dem where there are no discontinuous network while in river extracted from reprojected dem using bilinear and cubic method, there are so many river were discontinued.

GregBarrett2 · Answer

It sounds like your DEM could have been projected using nearest neighbor resampling, which is what you don't want with continuous data like a DEM. See the section titled, "Reprojecting the Right Way: Reprojecting Rasters with ArcToolbox" in this article for more information: https://www.esri.com/about/newsroom/arcuser/looking-good/