not working for this test case

[kunzhoudk]

@Test
public void test() {
    List<Point> points = new ArrayList<>();
    addPointToList(points, 119.65450502825215, 234.97190110269844);
    addPointToList(points, 120.94208471603682, 241.47274889005215);
    addPointToList(points, 120.57389187028015, 240.42380619065557);
    addPointToList(points, 120.40553233952696, 239.3249423106921);
    addPointToList(points, 120.44278575100797, 238.2138802324909);
    addPointToList(points, 120.68437322950616, 237.12876169126298);
    addPointToList(points, 121.12200129996195, 236.1068378045508);
    addPointToList(points, 121.74064659481407, 235.18319027576013);
    addPointToList(points, 122.51907159233552, 234.38952707167576);
    TestCase.assertTrue(SimplePolygonValidator.simplePolygon(GeometryTransformation.toPolygon(points)));
}

it is failed to detect the case where the polygon is self-intersecting.

[bosborn]

I am not sure what other(?) library you are using, but don't recognize the GeometryTransformation class, SimplePolygonValidator class, or even the addPointToList method.

Using the base simple feature classes (ignoring the geojson wrappers), the isSimple() method uses a Shamos-Hoey simple polygon detection.

@Test
public void test() {

	  LineString ring = new LineString();
	  ring.addPoint(new Point(119.65450502825215, 234.97190110269844));
	  ring.addPoint(new Point(120.94208471603682, 241.47274889005215));
	  ring.addPoint(new Point(120.57389187028015, 240.42380619065557));
	  ring.addPoint(new Point(120.40553233952696, 239.3249423106921));
	  ring.addPoint(new Point(120.44278575100797, 238.2138802324909));
	  ring.addPoint(new Point(120.68437322950616, 237.12876169126298));
	  ring.addPoint(new Point(121.12200129996195, 236.1068378045508));
	  ring.addPoint(new Point(121.74064659481407, 235.18319027576013));
	  ring.addPoint(new Point(122.51907159233552, 234.38952707167576));
	  Polygon polygon = new Polygon();
	  polygon.addRing(ring);
	  
	  TestCase.assertTrue(polygon.isSimple());
	  
	  ring.addPoint(new Point(119.65450502825215, 241.47274889005215));
	  
	  TestCase.assertFalse(polygon.isSimple());

}

[kunzhoudk]

Really sorry, I pasted the wrong codes but with right coordinates. In the test you created above, the polygon is a self-intersecting a polygon, why TestCase.assertTrue(polygon.isSimple()) passed, what is the definition of "Simple" here? see the figure, thanks

@Test
public void test() {

	LineString ring = new LineString();
	ring.addPoint(new Point(119.65450502825215, 234.97190110269844));
	ring.addPoint(new Point(120.94208471603682, 241.47274889005215));
	ring.addPoint(new Point(120.57389187028015, 240.42380619065557));
	ring.addPoint(new Point(120.40553233952696, 239.3249423106921));
	ring.addPoint(new Point(120.44278575100797, 238.2138802324909));
	ring.addPoint(new Point(120.68437322950616, 237.12876169126298));
	ring.addPoint(new Point(121.12200129996195, 236.1068378045508));
	ring.addPoint(new Point(121.74064659481407, 235.18319027576013));
	ring.addPoint(new Point(122.51907159233552, 234.38952707167576));
	Polygon polygon = new Polygon();
	polygon.addRing(ring);

	TestCase.assertTrue(polygon.isSimple());

}

[bosborn]

OK, thanks. Must be a bug in the ported code then. The original code has been take down, but this npm library seems to work for that case.

const isSimple = require('shamos-hoey')

const box = {type: 'Polygon', coordinates: [[
[119.65450502825215, 234.97190110269844], 
[120.94208471603682, 241.47274889005215], 
[120.57389187028015, 240.42380619065557], 
[120.40553233952696, 239.3249423106921], 
[120.44278575100797, 238.2138802324909], 
[120.68437322950616, 237.12876169126298], 
[121.12200129996195, 236.1068378045508], 
[121.74064659481407, 235.18319027576013], 
[122.51907159233552, 234.38952707167576]]]}
isSimple(box)

false

[bosborn]

ngageoint/simple-features-java#1

[bosborn]

To be fixed in simple features version 2.2.1, simple features geojson version 3.3.2.

[bosborn]

Fixed in version 3.3.2 through simple features version 2.2.1