boolean-within returning false positives at horseshoe polygons

[RobertOrthofer]

Please provide the following when reporting an issue:

• The version of Turf you are using, and any other relevant versions.

@turf/boolean-within 6.3.0

• GeoJSON data as a gist file or geojson.io (filename extension must be .geojson).

https://gist.github.com/RobertOrthofer/cf45710fabdcbde73d2b5e39b4deebd9

Code to reproduce in RunKit:
https://runkit.com/embed/7bxlrywqnurr

boolean-within falsely returns true for horseshoe polygons intersecting a simple line features. By that i mean Polygons shaped like a U, intersecting, but not fully containing a LineString. At first i thought i misinterpreted the docs, but adding just an additional segment to the LineString outside the Polygon makes booleanWithin return false, which seems correct to me.

This is probably related to #2049 and #1897

[kudlav]

Same the following, returns true but it shouldn't:

turf.booleanWithin(
  {
    type: "Feature",
    properties: {},
    geometry: {
      type: "LineString",
      coordinates: [ [9.15, 32.46], [12.33, 41.6] ],
    },
  },
  {
    type: "Feature",
    properties: {},
    geometry: {
      type: "Polygon",
      coordinates: [
        [ [-0.64, 23.73], [0.89, 24.06], [0.91, 24.34], [1.65, 24.58], [2.22, 24.89], [2.48, 25.14], [2.9, 25.78], [2.78, 25.86], [3.95, 28.17], [4.16, 28.05], [5.36, 30.12], [5.38, 30.25], [5.48, 30.34], [5.49, 30.49], [5.57, 30.55], [5.57, 30.66], [5.67, 30.77], [5.69, 30.9], [5.8, 31.04], [5.81, 31.11], [5.75, 31.23], [5.77, 31.3], [5.55, 31.44], [5.6, 31.54], [5.83, 31.43], [5.89, 31.53], [5.71, 31.7], [5.77, 31.79], [5.81, 31.77], [5.82, 31.79], [5.92, 31.72], [5.9, 31.7], [6, 31.66], [6.04, 31.7], [6.25, 31.59], [6.27, 31.57], [6.36, 31.23], [7.13, 31.6], [9.08, 32.05], [9.03, 32.42], [9.15, 32.46], [9.26, 32.45], [9.33, 32.18], [9.51, 32.21], [9.58, 31.88], [10.05, 31.93], [10.12, 31.7], [10.96, 31.97], [10.79, 32.39], [13.87, 33.69], [13.97, 33.68], [13.99, 33.55], [13.87, 33.5], [13.86, 33.47], [13.92, 33.33], [13.92, 33.29], [13.98, 33.25], [14, 33.19], [14.09, 33.2], [14.26, 33.26], [14.13, 33.54], [14.15, 33.58], [14.09, 33.63], [14.23, 33.63], [14.47, 33.77], [14.6, 33.79], [14.65, 33.88], [14.78, 33.93], [14.9, 33.93], [14.99, 33.97], [15.07, 33.57], [15.27, 33.6], [15.25, 33.87], [15.27, 33.87], [15.31, 33.55], [15.45, 33.55], [15.44, 33.72], [15.35, 33.8], [15.34, 33.84], [15.36, 33.86], [15.46, 33.76], [15.75, 33.72], [15.97, 33.73], [16.24, 33.66], [16.19, 33.24], [16.28, 33.21], [16.32, 33.2], [16.44, 33.32], [16.68, 33.24], [16.9, 33.27], [17.1, 33.19], [17.19, 33.3], [17.93, 33.36], [18.27, 33.25], [17.91, 32.5], [18.45, 32.33], [18.62, 32.87], [18.67, 32.86], [18.83, 32.7], [18.83, 32.65], [19.31, 32.51], [21.4, 32.27], [23.41, 32.26], [23.27, 33.59], [23.79, 34.31], [23.99, 34.46], [24.24, 34.54], [24.75, 34.52], [25.93, 34.61], [26.03, 34.67], [26.14, 34.68], [26.31, 34.38], [26.4, 34.42], [26.29, 34.63], [26.35, 34.65], [26.37, 34.63], [26.36, 34.58], [26.49, 34.38], [26.57, 34.32], [26.7, 34.32], [26.66, 34.66], [26.69, 34.72], [27.12, 34.89], [27.36, 35.2], [28.19, 37.15], [28.46, 37.95], [28.43, 38.03], [28.56, 38.13], [28.58, 38.07], [28.66, 37.99], [28.74, 38.06], [28.7, 38.11], [28.74, 38.18], [28.67, 38.28], [29.11, 38.62], [29.08, 38.65], [29.34, 38.86], [30.31, 39.88], [30.51, 40.01], [30.54, 40.08], [30.83, 40.15], [30.84, 40.11], [30.89, 40.13], [30.88, 40.16], [31.15, 40.25], [31.72, 40.38], [31.79, 40.07], [31.89, 40], [32.05, 40.05], [32.36, 40.08], [32.32, 40.16], [32.48, 40.22], [32.47, 40.26], [32.54, 40.29], [32.58, 40.17], [32.64, 40.15], [33.17, 40.25], [33.46, 40.4], [33.37, 40.75], [33.56, 40.79], [33.65, 40.46], [33.8, 40.11], [33.9, 40.16], [33.81, 40.48], [33.77, 40.8], [33.81, 40.81], [33.68, 41.6], [21.08, 41.6], [20.37, 41.21], [17.49, 41.15], [13.6, 41.36], [9.29, 39.94], [6.59, 39.49], [2.53, 38.38], [-0.3, 36.01], [-0.64, 35.35], [-0.64, 23.73] ],
      ],
    },
  }
);

Using turf@7.0.0-alpha.114
Broken even after simplifying using turf.simplify.

[kudlav]

turf-boolean-within wasn't testing if the last point of the LineString was within Polygon. I've created a fix in PR #2599

[kudlav]

Fixed in @turf/turf@7.0.0-alpha.115

[twelch]

Closing, please feel free to reopen @RobertOrthofer if this doesn't fix your particular use case.