gis.road_graph

Parameters

Name	Type	Mode
_road_code	text	IN
_marker_code	integer	IN
_abscissa	real	IN
_offset	real	IN
_side	text	IN

Definition

DECLARE
    get_downstream_multilinestring_from_reference record;
    _closest_marker_abscissa real;
    _downstream_road geometry(MULTILINESTRING, 2154);
    result_point geometry(POINT, 2154);
    raise_notice text;
BEGIN

-- Notice
    raise_notice = coalesce(current_setting('road.graph.raise.notice', true), 'no');

-- Add default values for offset and side if they are NULL
    _offset = Coalesce(_offset, 0.0);
    _side = Coalesce(_side, 'right');

-- Get downstream MULTILINESTRING
    SELECT
        closest_marker_abscissa,
        downstream_road
    FROM
        jsonb_to_record(
            road_graph.get_downstream_multilinestring_from_reference(
                _road_code, _marker_code, _abscissa
            )
        ) AS (
            road_code text, marker_code integer, abscissa real,
            closest_marker_abscissa real,
            downstream_road geometry(MULTILINESTRING, 2154)
        )
    INTO get_downstream_multilinestring_from_reference
    ;

_closest_marker_abscissa = get_downstream_multilinestring_from_reference.closest_marker_abscissa;
    _downstream_road = get_downstream_multilinestring_from_reference.downstream_road;

-- Return point
    SELECT INTO result_point
    ST_ReducePrecision(
        -- extract first point of resulting multipoint from ST_LocateAlong
        ST_GeometryN(
            -- Remove M measure from the result multipoint
            ST_Force2D(
                -- Locate the point on the measured downstream road part
                ST_LocateAlong(
                    -- Add measure to the downstream road part from 0 to length
                    ST_AddMeasure(_downstream_road, 0, ST_Length(_downstream_road)),
                    -- Abscissa cannot be above length
                    -- We must also add the marker abscissa
                    CASE
                        WHEN "_abscissa" - _closest_marker_abscissa >= ST_Length(_downstream_road)
                            THEN ST_Length(_downstream_road)
                        ELSE "_abscissa" - _closest_marker_abscissa
                    END,
                    -- JSON helper to choose side and offset
                    ((json_build_object('left', +1, 'right', -1))->>("_side"))::integer * "_offset"
                )
            )
            , 1
        ),
        0.01
    )::geometry(POINT, 2154)
    ;

-- Return full JSONb with parameters and computed geometry
    RETURN jsonb_build_object(
        'road_code', _road_code,
        'marker_code', _marker_code,
        'abscissa', _abscissa,
        'offset', _offset,
        'side', _side,
        'closest_marker_abscissa', _closest_marker_abscissa,
        'geom', result_point
    );

END;

get_road_point_from_reference(_road_code text, _marker_code integer, _abscissa real, _offset real, _side text)

Description

Parameters

Definition