I would like to delineate the polygon of a basin from an already delineated stream work. In the example, I want to extract an approximate polygon from the selected stream network in yellow without using a DEM. Any solution in ArcGIS?

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  • Welcome back to GIS SE. Please take the time to complete our Tour. Unfortunately our "Focused question / Best answer" model requires one question per Question, and calling out three different GIS software options is effectively three questions. Please choose one package, research basin delineation with that package, and alter this question to focus on any problem you encounter. – Vince Jan 21 '18 at 15:48
  • Fixed! It is not the same question as I don't use as input a DEM. – Guido A. Herrera Jan 21 '18 at 16:00
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    Assign 1 to selected, assign 2 to the rest. Use euclidian allocation, convert raster to polygons and clip by catchment. network is dense enough to expect reasonable result. – FelixIP Jan 21 '18 at 16:42
  • @FelixIP I think their desire not to use a DEM is suggesting that they do not have the Spatial Analyst extension as any other approach will be a crude approximation, not honouring watershed boundaries. The euclidean allocation tool requires the Spatial Analyst extension. Guido if you do Have the SA extension then you can download free SRTM data to construct catchment boundaries with. Or have a look at HYDROSHEDS before you invest too much effort. – Hornbydd Jan 21 '18 at 19:52

If you insist on not using a DEM, you can use trace upstream from utility network analysis toolbar, and then create an convex hull of the selected network using Minimum Bounding Geometry.

But the resulting convex hull should be only an approximation of the real catchment area polygon.

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