# skspatial.objects.Line.transform_points¶

Line.transform_points(points: Union[ndarray, Sequence]) [source]

Transform points to a one-dimensional coordinate system defined by the line.

The point on the line acts as the origin of the coordinate system.

This is analogous is projecting the points onto the line, then computing the signed distance from the line point to the projections.

Parameters
points(N, D) array_like

Array of N points with dimension D.

Returns
ndarray

(N,) array of N coordinates.

Examples

```>>> from skspatial.objects import Line
```
```>>> points = [[-1, 1], [0, 1], [1, 1], [2, 1]]
```
```>>> Line([0, 0], [1, 0]).transform_points(points)
array([-1.,  0.,  1.,  2.])
```

The point on the line acts as the origin of the coordinates.

```>>> Line([1, 0], [1, 0]).transform_points(points)
array([-2., -1.,  0.,  1.])
```

The sign of the coordinates depends on the direction of the line.

```>>> Line([0, 0], [-1, 0]).transform_points(points)
array([ 1.,  0., -1., -2.])
```

The magnitude of the direction vector is irrelevant.

```>>> Line([0, 0], [5, 0]).transform_points(points)
array([-1.,  0.,  1.,  2.])
```