# Calculating length downstream of edges in a network

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?

• If you are able to compute all distances, one set of them are distances to outlet.? – FelixIP Apr 18 at 22:55
• I added a picture. We went to know the downstream distance between any two points, not to the outlet. – wingingit Apr 22 at 18:29
• Why is it not 80/110? What was the logic to choose 30/110? – Hornbydd Apr 23 at 18:00
• It could be 80/110, its just the inverse so either number is acceptable. The purpose of having this proportion for each point is to help in a statistical model that will try to guess where new communities may pop up. (higher downstream proportion/lower upstream proportion between point and a large number of other points = likely spot for a community) – wingingit Apr 23 at 19:38
• If steps 6 or 7 from this documentation don't work, I would try focusing on the line features as feature classes and using the Geometry Attributes tool. – Jacob Helfman Jul 28 at 23:36