cityImage.clean_duplicate_edges#

cityImage.clean_duplicate_edges(nodes_gdf, edges_gdf, preserve_direction=False)[source]#

Cleans and deduplicates network edges, and removes unused nodes.

The function performs the following:

  • Generates a unique ‘code’ for each edge, based on node IDs, with or without preserving direction.

  • Removes self-loop edges (edges from a node to itself).

  • Drops duplicate edges based on geometry (including reversal if direction is not preserved).

  • Removes edges that are geometrically duplicates, even if node order is reversed (for undirected graphs).

  • Updates the node GeoDataFrame to keep only those nodes actually used by the remaining edges.

Parameters:

  • nodes_gdf (GeoDataFrame) – GeoDataFrame containing nodes, must include a ‘nodeID’ column.

  • edges_gdf (GeoDataFrame) – GeoDataFrame containing edges, must include ‘u’, ‘v’, and ‘geometry’ columns.

  • preserve_direction (bool, optional) – If True, edge direction is preserved; edges (u,v) and (v,u) are considered distinct. If False, edges are treated as undirected and geometric duplicates (with reversed coords) are removed. Default is False.

Returns:

  • nodes_gdf (GeoDataFrame) – Filtered nodes GeoDataFrame, containing only nodes referenced by the cleaned edges.

  • edges_gdf (GeoDataFrame) – Cleaned edges GeoDataFrame, deduplicated and without self-loops.