Match streets to rivers with attention to underlying DEM

[barneydobson]

I don't think I agree with the logic here. Using only a buffer distance to identify a water body that a node can drain to is not necessarily hydraulically feasible. A raindrop trace operation needs to be done to ensure that a water body exists at the downstream of nodes (so it can drain to) and, if desired, within an allowable distance. You can do this with pyflwdir.

I think I should've phrased my question better. I understand what this specific set of functions is doing, but my question was: How does it fit in the overall workflow? When do these get applied, and what information is included at this stage? IMHO, only using elevation to determine the outlet location is impractical. In practice, a lot more considerations, especially environmental ones, go into selecting them. So, I am trying to understand the implications of relying solely on the elevation data for this purpose.

Off the top of my head, two of the most important factors are the min discharge velocity at the outfall (in the US, depending on the municipality it can be 5, 10, or 20 ft/s) and existence of fish habitat and such in the water body.

Originally posted by @cheginit in #144 (comment)

I think in general can use this issue to discuss which factors are important for outfall identification:

• Network topology (included with Improve identify outlets #144 )
• DEM (as mentioned above)
• Environmental considerations (@cheginit do you mean by this like flow in the receiving water body?)
• Minimum velocity required

.. any other factors?