[GitHub] [lucene] iverase opened a new issue, #11883: Spatial3d: Wrong intersection detected between small polygons

[GitBox]

iverase opened a new issue, #11883:
URL: https://github.com/apache/lucene/issues/11883

   ### Description
   
   The following polygon corresponds to the uber h3 boundary cell 
"8cc373cb54069ff":
   ```
   POLYGON((-64.2102198418716 -39.14233318389477,-64.21016450005413 
-39.142267144439614,-64.21021077465937 -39.1421844504783,-64.21031239098929 
-39.142167795785085,-64.2103677330169 -39.14223383513698,-64.21032145850448 
-39.14231652928534,-64.2102198418716 -39.14233318389477))
   ```
   
   And this polygon  corresponds to the uber h3 boundary cell "8cc373cb54065ff":
   
   ```
   POLYGON((-64.20991499254879 -39.14238314705201,-64.20985965132967 
-39.14231710755475,-64.20990592624541 -39.142234413886875,-64.21000754228744 
-39.142217759529174,-64.21006288371667 -39.14228379892317,-64.21001660889377 
-39.14236649277811,-64.20991499254879 -39.14238314705201))"
   ```
   The cells are close to each other but they are not neighbours:
   
   <img width="177" alt="image" 
src="https://user-images.githubusercontent.com/29038686/198230964-f8fe118b-5b78-4780-a04d-b9558d07063c.png";>
   
   Still if you construct them with spatial3d library, the library detects and 
intersection between them:
   
   ```
    public void testH3CellsWrongIntersection() {
       final List<GeoPoint> points1 = new ArrayList<>();
       addToList(points1, PlanetModel.SPHERE, -64.2102198418716, 
-39.14233318389477);
       addToList(points1, PlanetModel.SPHERE, -64.21016450005413, 
-39.142267144439614);
       addToList(points1, PlanetModel.SPHERE, -64.21021077465937, 
-39.1421844504783);
       addToList(points1, PlanetModel.SPHERE, -64.21031239098929, 
-39.142167795785085);
       addToList(points1, PlanetModel.SPHERE, -64.2103677330169, 
-39.14223383513698);
       addToList(points1, PlanetModel.SPHERE, -64.21032145850448, 
-39.14231652928534);
       final List<GeoPoint> points2 = new ArrayList<>();
       addToList(points2, PlanetModel.SPHERE, -64.20991499254879, 
-39.14238314705201);
       addToList(points2, PlanetModel.SPHERE, -64.20985965132967, 
-39.14231710755475);
       addToList(points2, PlanetModel.SPHERE, -64.20990592624541, 
-39.142234413886875);
       addToList(points2, PlanetModel.SPHERE, -64.21000754228744, 
-39.142217759529174);
       addToList(points2, PlanetModel.SPHERE, -64.21006288371667, 
-39.14228379892317);
       addToList(points2, PlanetModel.SPHERE, -64.21001660889377, 
-39.14236649277811);
      
       final GeoPolygon polygon1 = 
GeoPolygonFactory.makeGeoPolygon(PlanetModel.SPHERE, points1);
       final GeoPolygon polygon2 = 
GeoPolygonFactory.makeGeoPolygon(PlanetModel.SPHERE, points2);
       assertFalse(polygon1.intersects(polygon2));
     }
   
     private static void addToList(List<GeoPoint> points, PlanetModel 
planetModel, double lon, double lat) {
       points.add(
               new GeoPoint(
                       planetModel,
                       Geo3DUtil.fromDegrees(lat),
                       Geo3DUtil.fromDegrees(lon)));
     }
   ```
   A quick look make me think the issue is related with the current vector 
minimum resolution. 
   
   Taking into account that those cells are at H3 resolution 12 which means the 
[average 
area](https://h3geo.org/docs/core-library/restable/#average-area-in-m2) of 
those hexagons is 307.092 m2, I think we should be able to detect spatial 
relationships properly.
   
   
   <br class="Apple-interchange-newline">  
   
   
   
   ### Version and environment details
   
   _No response_


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