Using booleanContains cannot accurately determine the inclusion result of line segments and concave convex polygons

[Steve245270533]

Using booleanContains cannot accurately determine the inclusion result of line segments and concave convex polygons.

version: 6.5.0

import { lineString, polygon, booleanContains } from '@turf/turf';

const turf_polygon = polygon([
  [
    [0, 0],
    [4, 0],
    [4, 1],
    [3, 1],
    [3, 2],
    [2, 2],
    [2, 1],
    [1, 1],
    [1, 3],
    [0, 3],
    [0, 0],
  ],
]);

const turf_line = lineString([
  [1, 2],
  [4, 0],
]);

console.log(booleanContains(turf_polygon, turf_line));

The final result is true, and it is evident from the image that this line segment is not completely contained within the polygon.

I'm not sure if there's a problem with my usage. Is there any way to correctly determine the inclusion of line segments and polygons?

[oscar9]

I'm also having the same issue with a very similar case. Thanks in advance.

For the case geometry 1 is polygon, geometry 2 is line. Looking at the code, looks like the issue is in isLineInPoly method. To calculate if the line is contained in the polygon, it only checks if the mid point of that line is inside the polygon. https://github.com/Turfjs/turf/blob/88dfdbb2617b70c833e30923590400dc0189e601/packages/turf-boolean-contains/index.ts#L196C27-L196C27
In the above case, the mid point of the red line is inside the polygon.

[samuelarbibe]

Hey! added a PR to fix this.
#2848

[Janickvw]

Having the same issues. Is there any updates on getting #2848 merged in @samuelarbibe? Thanks for getting a PR up.

[samuelarbibe]

Waiting for a review from a maintainer :)

[smallsaucepan]

Related issue with different geometries at #2595 (poly / poly). The issues are related in as much as they return false positives if all the points are inside, without noting whether the lines between the points venture outside the other polygon.

Not suggesting this PR needs to fix that as well - just that the issues (and fixes) might have similarities.