Function line_locate_point 

pub fn line_locate_point<L, P>(line: &L, point: &P) -> Option<f64>
where
    L: Linestring<Point = P>,
    P: Point<Scalar = f64> + PointMut + Default + Copy,
    <P::Cs as CoordinateSystem>::Family: SameAs<CartesianFamily>,
    CartesianClosestPoints: ClosestPointsStrategy<P, Segment<P>, Out = P>,
    Pythagoras: DistanceStrategy<P, P, Out = f64>,

Return the fractional arc-length position nearest to point.

Returns None for an empty linestring and Some(0.0) for a single-point or zero-length linestring. Ties retain the earliest position along the line.