gis.road_graph

Parameters

Name	Type	Mode
_params	jsonb	IN

Definition

DECLARE
    edge record;
    keep_node record;
    remove_node_id integer;
    extended_edge_id integer;
BEGIN
    -- The edge may have been removed or modified by a previous fix
    SELECT e.*
    INTO edge
    FROM road_graph.edges AS e
    WHERE e.id = (_params->>'edge_id')::integer
    ;
    IF edge.id IS NULL THEN
        RETURN jsonb_build_object(
            'status', 'skipped',
            'message', format('The edge %s does not exist anymore', _params->>'edge_id')
        );
    END IF;
    IF NOT ARRAY[edge.start_node, edge.end_node] @> ARRAY[
        (_params->>'keep_node_id')::integer, (_params->>'remove_node_id')::integer
    ] THEN
        RETURN jsonb_build_object(
            'status', 'skipped',
            'message', format('The nodes of the edge %s have changed', edge.id)
        );
    END IF;
    IF (SELECT count(*) FROM road_graph.edges AS e WHERE e.road_code = edge.road_code) = 1 THEN
        RETURN jsonb_build_object(
            'status', 'error',
            'message', format('The edge %s is the only edge of the road %s', edge.id, edge.road_code)
        );
    END IF;
    -- An edge starting and ending at the same node, for example an edge reduced to a point
    -- after being cut, is only deleted
    IF edge.start_node = edge.end_node THEN
        DELETE FROM road_graph.edges AS e
        WHERE e.id = edge.id
        ;
        RETURN jsonb_build_object(
            'status', 'success',
            'message', format(
                'The edge %s starting and ending at the node %s has been deleted', edge.id, edge.start_node
            )
        );
    END IF;

SELECT n.*
    INTO keep_node
    FROM road_graph.nodes AS n
    WHERE n.id = (_params->>'keep_node_id')::integer
    ;
    remove_node_id = (_params->>'remove_node_id')::integer;

-- The edges extended or moved below run along the short edge and pass near the node to remove:
    -- the variables prevent the triggers from splitting them at the crossings with the short edge
    -- and at the node to remove (see after_edge_insert_or_update)
    PERFORM set_config('road.graph.edge.crossing.node.creation.pending', 'yes', true);
    PERFORM set_config('road.graph.merge.edges.useless.node', remove_node_id::text, true);

-- The edge of the same road following the short edge at the node to remove, if there is only one,
    -- is extended with the geometry of the short edge up to the node to keep: the geometry of the road is kept
    SELECT e.id
    INTO extended_edge_id
    FROM road_graph.edges AS e
    WHERE e.road_code = edge.road_code
    AND e.id != edge.id
    AND (
        (remove_node_id = edge.end_node AND e.start_node = remove_node_id)
        OR (remove_node_id = edge.start_node AND e.end_node = remove_node_id)
    )
    AND (
        SELECT count(*)
        FROM road_graph.edges AS x
        WHERE x.road_code = edge.road_code
        AND x.id != edge.id
        AND remove_node_id IN (x.start_node, x.end_node)
    ) = 1
    ;
    IF extended_edge_id IS NOT NULL THEN
        UPDATE road_graph.edges AS e
        SET geom = ST_RemoveRepeatedPoints(
            CASE
                WHEN remove_node_id = edge.end_node THEN ST_MakeLine(edge.geom, e.geom)
                ELSE ST_MakeLine(e.geom, edge.geom)
            END
        )
        WHERE e.id = extended_edge_id
        ;
    END IF;

-- Move the start and end points of the other edges of the node to remove to the node to keep,
    -- for example the edges of the other roads: the triggers use the closest node, i.e. the node to keep
    UPDATE road_graph.edges AS e
    SET geom = ST_SetPoint(e.geom, 0, keep_node.geom)
    WHERE e.start_node = remove_node_id
    AND e.id != edge.id
    ;
    UPDATE road_graph.edges AS e
    SET geom = ST_SetPoint(e.geom, ST_NPoints(e.geom) - 1, keep_node.geom)
    WHERE e.end_node = remove_node_id
    AND e.id != edge.id
    ;
    PERFORM set_config('road.graph.edge.crossing.node.creation.pending', 'no', true);
    PERFORM set_config('road.graph.merge.edges.useless.node', '-1', true);

-- Delete the short edge, then the node to remove if it is not used anymore
    DELETE FROM road_graph.edges AS e
    WHERE e.id = edge.id
    ;
    DELETE FROM road_graph.nodes AS n
    WHERE n.id = remove_node_id
    AND NOT EXISTS (
        SELECT 1
        FROM road_graph.edges AS e
        WHERE remove_node_id IN (e.start_node, e.end_node)
    )
    ;

-- Check no edge uses the node to remove anymore.
    -- If not, the exception cancels the changes of this fix (see fix_graph_issue)
    IF EXISTS (
        SELECT 1
        FROM road_graph.edges AS e
        WHERE remove_node_id IN (e.start_node, e.end_node)
    ) THEN
        RAISE EXCEPTION 'The edges of the node % could not be moved to the node %', remove_node_id, keep_node.id;
    END IF;

RETURN jsonb_build_object(
        'status', 'success',
        'message', format(
            'The edge %s has been deleted%s, and the edges of the node %s have been moved to the node %s',
            edge.id,
            CASE
                WHEN extended_edge_id IS NULL THEN ''
                ELSE format(' and its geometry added to the edge %s', extended_edge_id)
            END,
            remove_node_id, keep_node.id
        )
    );
END;

fix_graph_collapse_edge(_params jsonb)

Description

Parameters

Definition