Proximity Graphs
The Proximity Graphs panel builds spatial networks from feature objects: single-layer graphs (KNN, radius, Delaunay…), multi-layer graphs that connect different feature types, and group-node graphs that link polygons to the points they contain. It is split into five subpanels.
The header subpanel only describes the capability. Generation parameters live in the Single-Layer, Multi-Layer, and Group Nodes subpanels, while Advanced Settings and Visualization apply across them.
Feature inputs must be City2Graph/OSM feature objects (a green checkmark with the feature count confirms a valid object). Both OSMnx feature objects and Overture/city2graph objects (such as building_overture) are accepted; polygon or line inputs are reduced to one representative point per feature automatically. Use Get as Points or Convert to Centroids in Data Import when you want explicit point inputs. The shared feature selector in Data Import and OSMnx Features can create these objects from Overture layers, OSMnx presets, or custom OSM tags such as amenity=restaurant.
Subpanel — Single-Layer Graphs
Builds one graph over a single set of features.
| Control | Description |
|---|---|
| Features | The feature object to build the graph from. |
| Graph Type | Topology rule (see table below). |
| Distance Metric | Euclidean, Manhattan, or Network (shortest path along an OSMnx street network). |
| Network | Required when the metric is Network: the OSMnx street network object. |
Graph types
| Type | Meaning | Extra parameter |
|---|---|---|
| K-Nearest Neighbors | Connect each node to its K closest nodes. | K (Neighbors) — must be < feature count. |
| Delaunay | Delaunay triangulation. | — |
| Fixed Radius | Connect all nodes within a distance (Gilbert graph). | Radius (meters). |
| Waxman | Probabilistic graph; edge likelihood decays with distance. | Beta, R0, Seed. |
| Gabriel | Gabriel graph (a subset of Delaunay). | — |
| Relative Neighborhood | Relative Neighborhood Graph (RNG). | — |
| EMST | Euclidean Minimum Spanning Tree. | — |
| Contiguity | Polygon adjacency graph. | Contiguity Type: Queen (share edges or vertices) / Rook (share only edges). |
Generate Graph builds the network.
Subpanel — Multi-Layer Graphs
Connects features across layers (e.g. restaurants → hospitals → schools).
| Control | Description |
|---|---|
| Layer 1 / Layer 2 | The two required feature layers. |
| Layer 3 (Optional) | A third optional layer. |
| Method | K-Nearest Neighbors (set K) or Fixed Radius (set Radius). |
| Metric | Euclidean / Manhattan / Network (with a Network object). |
| Generate Multi-Layer Graph | Builds the cross-layer bridge graph; per-edge-type attributes are created for coloring. |
Subpanel — Group Nodes (Polygon → Point)
Connects polygon zones to the points they contain (e.g. districts → buildings).
| Control | Description |
|---|---|
| Polygons | Polygon feature object (zones). |
| Points | Point feature object. |
| Predicate | Containment rule: Covered By, Within (strict interior), or Intersects (boundary or interior). |
| Metric | Euclidean / Manhattan / Network (with a Network object). |
| Generate Group Nodes | Connects each point to its containing polygon(s). |
Subpanel — Advanced Settings
Controls duplicate handling, useful when OSM ways/relations were imported as many vertices.
| Control | Description |
|---|---|
| Deduplicate Points | Merge coincident points before building the graph. |
| Dedup Tolerance | Points within this distance (meters) are merged. |
Subpanel — Visualization
Controls how generated edges and nodes are displayed.
| Control | Description |
|---|---|
| Edge Thickness | Thickness of the curve edges. |
| Visualize Limit | Maximum number of edges to render (caps very dense graphs). |
| Color by Attribute | Tag nodes/edges with per-type attributes. Inspect them in the Spreadsheet editor and drive colors via Geometry Nodes or shaders. |
Step-by-step tutorial
For a worked example using Burjassot, follow Build proximity graphs.