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name: graph-modeling-io description: "Manipulate OSMnx NetworkX/GeoPandas graph data structures and persist or restore them safely." disable-model-invocation: true metadata: disco-role: operating license: MIT

Graph Modeling and I/O

Use this sub-skill when the task is about an existing OSMnx graph or GeoDataFrame: validating its schema, converting between NetworkX and GeoPandas representations, projecting CRS, simplifying or consolidating topology, truncating components, or saving/loading graph files.

Route here

• Validate OSMnx graph, node/edge GeoDataFrame, or features GeoDataFrame invariants.
• Convert MultiDiGraph/MultiGraph objects to/from node and edge GeoDataFrames.
• Create directed/undirected graph views with to_digraph or to_undirected.
• Project geometries, GeoDataFrames, or graphs with project_geometry, project_gdf, or project_graph.
• Simplify topology, consolidate intersections, truncate by distance/bbox/polygon, or keep the largest weak/strong component.
• Persist or restore graph data with GraphML, GeoPackage, or OSM XML.

Route elsewhere

• Downloading, geocoding, Overpass/Nominatim settings, OSM tag queries, or local XML acquisition belong to data-acquisition.
• Nearest-node/edge search, route computation, network statistics, bearings, orientation entropy, speeds, or travel times belong to routing-analysis.
• Elevation, grade calculation, and plotting belong to elevation-visualization.

Operating references

Read these before acting:

1. Data model and transformations for graph/GDF invariants, validation, conversion, projection, simplification, consolidation, truncation, and difficult recovery patterns.
2. Persistence and file formats for GraphML, GeoPackage, OSM XML, dtype restoration, and format-choice rules.
3. Troubleshooting graph modeling and I/O for predictable validation, CRS, simplification, truncation, and save/load failures.

Bundled smoke script:

• Graph/GDF/GraphML smoke test creates a tiny graph, validates it, round-trips through GeoDataFrames, saves/loads GraphML in a temporary directory, and prints a concise success summary.

Minimal workflow

1. Identify the object type: OSMnx networkx.MultiDiGraph, node/edge GeoDataFrames, features GeoDataFrame, geometry, or file path.
2. Validate early with osmnx.convert.validate_graph, validate_node_edge_gdfs, or validate_features_gdf.
3. Normalize the data model before analysis or persistence: ensure CRS, node x/y, edge (u, v, key) index, edge osmid, and edge length are present with compatible types.
4. Use projection before distance/tolerance operations that require metric units, then project back to lat-long only when needed for geographic output.
5. Choose persistence format deliberately: GraphML for future OSMnx work, GeoPackage for GIS layer exchange, OSM XML only for unsimplified/unprojected OSM-style export.
6. Run the bundled smoke script when an environment or installation may be suspect.