S2polygon.getCentroid seems wrong in some case?

I encountered a problem where the centroid seems wrong, i.e., the centroid is outside the polygon even when the polygon itself is a convex.

The code below plots a hexagon but the centroid seems to be way off, did I do anything wrong, thanks a lot for help?

double[] coordinates = new double[]{
47.167511,-122.1521,
47.167568,-122.151952,
47.167684,-122.151952,
47.167746,-122.1521,
47.167691,-122.152248,
47.16757,-122.152248,
47.167511,-122.1521,
};
List s2Points = new ArrayList<>();
for (int i = 0; i < coordinates.length /2; i++) {
double lat = coordinates[2 * i];
double lng = coordinates[2 * i + 1];
System.out.println(lat + "," + lng + ",");
S2LatLng s2LatLng = S2LatLng.fromDegrees(lat, lng);
s2Points.add(s2LatLng.toPoint());
}
S2Loop s2Loop = new S2Loop(s2Points);
s2Loop.normalize();
S2Polygon s2Polygon = new S2Polygon(s2Loop);
S2Point s2PolygonCentroid = s2Polygon.getCentroid();
System.out.println("Center: " + s2PolygonCentroid.toDegreesString() + " in_polygon " + s2Polygon
.contains(s2PolygonCentroid));

Output:
Center: (47.167557150782145, -122.15163675765044) in_polygon false

Kml file:

layer

<LineStyle>
<color>ff000000</color>
<width>1.2000000476837158</width>
</LineStyle>
<PolyStyle>
<color>4d000000</color>
<fill>1</fill>
<outline>1</outline>
</PolyStyle>
<BalloonStyle>
<text>&lt;![CDATA[&lt;h3&gt;$[name]&lt;/h3&gt;]]&gt;</text>
</BalloonStyle>


<LineStyle>
<color>ff000000</color>
<width>1.7999999523162842</width>
</LineStyle>
<PolyStyle>
<color>4d000000</color>
<fill>1</fill>
<outline>1</outline>
</PolyStyle>
<BalloonStyle>
<text>&lt;![CDATA[&lt;h3&gt;$[name]&lt;/h3&gt;]]&gt;</text>
</BalloonStyle>



normal
#style-polygon-normal


highlight
#style-polygon-highlight



<LineStyle>
<color>ff000000</color>
<width>1.2000000476837158</width>
</LineStyle>
<PolyStyle>
<color>4d000000</color>
<fill>1</fill>
<outline>1</outline>
</PolyStyle>
<BalloonStyle>
<text>&lt;![CDATA[&lt;h3&gt;$[name]&lt;/h3&gt;]]&gt;</text>
</BalloonStyle>


<LineStyle>
<color>ff000000</color>
<width>1.7999999523162842</width>
</LineStyle>
<PolyStyle>
<color>4d000000</color>
<fill>1</fill>
<outline>1</outline>
</PolyStyle>
<BalloonStyle>
<text>&lt;![CDATA[&lt;h3&gt;$[name]&lt;/h3&gt;]]&gt;</text>
</BalloonStyle>



normal
#style-s2cell-normal


highlight
#style-s2cell-highlight



test
test
#style-polygon




-122.15210000000002,47.167511 -122.151952,47.16756800000001 -122.15195200000002,47.16768400000001 -122.15210000000002,47.167746 -122.15224799999999,47.167691000000005 -122.15224799999999,47.16757 -122.15210000000002,47.167511




-122.15163675765044,47.167557150782145

提供された S2Loop/S2Polygon の再現ケースと S2Polygon.getCentroid の呼び出しから始め、緯度/経度の値がどのように S2Point インスタンスになるかを確認します。返された点をポリゴンの座標および contains の結果と比較します。完了条件は、報告された外部の点の原因が重心計算にあるのか入力の解釈にあるのかを特定し、それを回帰テストでカバーすることです。

索引モデルが issue の本文から書いたものです。