Set Flow Direction (Trace Network)


Sets the flow direction of line features in a version 1 trace network.


  • Flow direction can only be set with Set Flow Direction tool for line features that participate in a version 1 trace network.


    The Set Flow Direction tool is not supported with Trace Network Version 2 or later. Use the FLOWDIRECTION network attribute field to set or modify the flow direction of a line feature in the network.

  • The network topology must be enabled.

  • Flow direction can be specified at the feature level with digitized direction, against digitized direction, or as indeterminate. When a selection of features exists on the map, the flow direction will be set for only those features.

    Learn more about how to set flow direction

Syntax, in_edges, flow_direction)
ParameterExplanationData Type

The trace network that contains the line feature class on which the flow direction will be set.


This parameter requires a Trace Network Version 1 as input.

Trace Network; Trace Network Layer

The polyline features that participate in the input trace network.

Feature Layer

Specifies the flow direction of the edges.

  • WITH_DIGITIZED_DIRECTIONFlow direction will be along the digitized direction of the edges.
  • AGAINST_DIGITIZED_DIRECTIONFlow direction will be against the digitized direction of the edges.
  • INDETERMINATEFlow direction will be indeterminate.

Derived Output

NameExplanationData Type

The updated trace network.

Trace Network

Code sample

SetFlowDirection example (Python window)

Set the flow direction with digitized direction for the HydroLines edge class.

import arcpy
                          "HydroLines", "WITH_DIGITIZED_DIRECTION")


This tool does not use any geoprocessing environments.

Licensing information

  • Basic: No
  • Standard: Yes
  • Advanced: Yes

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