I have a fairly complex and large river system that I would like to calculate length downstream between any two points within the river network. I have a calculation between any two points in the network in distance, but not downstream distance.
The river system was generated from aerial photography. It is connected as a network (it successfully produced distance between all points of interest in the network using network analyst). It also has river order. We are imposing flow on the river system now.
I made a trial geometric network with a simple river line I drew. I assigned a hydroID and generated From/To Nodes along the line. It populates the field "LENGTHDOWN" with 0s when I run "Calculate Length Downstream for Edges". Not sure what's up.
What is a workflow for being able to use the "calculate length downstream for edges" in the archydro toolbox using a river line generated not from a DEM?