I am using QGIS in order to delineate a watershed, and am using 1/3 arcsecond DEMs. I have created a Filled DEM using the SAGA Fill Sinks xxl (Wang & Liu) tool. Next I ran the SAGA Channels and Drainage Basins tool, where the Channels were the only useful result. From here, using the Coordinate Capture plugin I was able to exact a coordinate point on the most downstream part of the channel (or river in this case) that I am trying to create the watershed of.
From here, I ran the SAGA Upslope Area tool using the Filled DEM raster and the (x,y) coordinate I just captured. The resulting layer that I created, however, was all black and the histogram distribution is
max=0. Why does this Upslope Area Layer not give me a result in which the
min = 0 and the
max = 100 and the resulting layer shows me the Upslope portion above that point in white and everything else in black?
What would the sources of my problems be? How do I fix them?