City2Graph · Map an OD matrix

Turn an external origin-destination flow matrix plus a zones layer into a spatial graph, with edges drawn between zone centroids and weighted by flow.

This walkthrough mirrors the Mobility panel.

Before you begin

Prepare two things:

  • A zones object (polygons) with a unique ID column — load it in Import urban data (Load File).
  • An OD matrix CSV (edgelist or adjacency) of flows between those zone IDs.

1. Set the zones

In Mobility, set the Zones Object and the Zone ID Column (e.g. zone_id) that matches the IDs in your matrix.

Selecting the zones object and ID column.

2. Load the OD matrix

Set the OD Matrix Path, choose the Matrix Type (Edgelist or Adjacency) and, for edgelists, the Source, Target and Weight columns. Press Load OD Matrix.

Loading the OD matrix and mapping its columns.

3. Build the OD graph

Set a Threshold to drop weak flows and toggle Directed, then press OD to Graph. Edges are drawn between zone centroids and weighted by flow.

The OD flow graph between zone centroids.

Next steps

Continue with Post-process a graph to filter, clip or build isochrones on any graph.

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