jiayuasu commented on code in PR #2831:
URL: https://github.com/apache/sedona/pull/2831#discussion_r3104407590
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common/src/main/java/org/apache/sedona/common/geography/Functions.java:
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@@ -75,14 +71,91 @@ private static S2Polygon rectToPolygon(double lngLo, double
latLo, double lngHi,
v.add(S2LatLng.fromDegrees(latHi, lngLo).toPoint());
S2Loop loop = new S2Loop(v);
- // Optional: normalize for canonical orientation (keeps the smaller-area
side)
loop.normalize();
return new S2Polygon(loop);
}
+ // ─── Level 1: JTS-only structural operations ─────────────────────────────
+
+ /** Return the number of points in a geography. */
+ public static int nPoints(Geography g) {
+ if (g == null) return 0;
+ return toJTS(g).getNumPoints();
+ }
+
+ // ─── Level 2: JTS + S2 geodesic metrics ──────────────────────────────────
+
+ /**
+ * Geometry-to-geometry geodesic distance in meters. Uses S2ClosestEdgeQuery
for true minimum
+ * distance between any two points on the geometries (not
centroid-to-centroid). Consistent with
+ * sedona-db's s2_distance implementation.
+ */
+ public static Double distance(Geography g1, Geography g2) {
+ if (g1 == null || g2 == null) return null;
+ if (g1 instanceof WKBGeography && g2 instanceof WKBGeography) {
+ WKBGeography w1 = (WKBGeography) g1;
+ WKBGeography w2 = (WKBGeography) g2;
+ // Fast path: point-to-point distance without building ShapeIndex
+ if (w1.isPoint() && w2.isPoint()) {
+ S1Angle angle = new S1Angle(w1.extractPoint(), w2.extractPoint());
+ return angle.radians() * EARTH_RADIUS_METERS;
+ }
+ // Fast path: point-to-complex uses PointTarget (avoids building
ShapeIndex for point side)
+ if (w1.isPoint()) {
+ double radians = Distance.S2_distancePointToIndex(w1.extractPoint(),
toShapeIndex(w2));
+ return radiansToMeters(radians);
+ }
+ if (w2.isPoint()) {
+ double radians = Distance.S2_distancePointToIndex(w2.extractPoint(),
toShapeIndex(w1));
+ return radiansToMeters(radians);
+ }
+ }
+ // General path via ShapeIndex
+ Distance dist = new Distance();
+ double radians = dist.S2_distance(toShapeIndex(g1), toShapeIndex(g2));
+ return radiansToMeters(radians);
+ }
+
+ // ─── Level 3: S2 spherical predicates ────────────────────────────────────
+
+ /** Spherical containment test using S2 boolean operations. */
+ public static boolean contains(Geography g1, Geography g2) {
+ if (g1 == null || g2 == null) return false;
+ // A point (dimension 0) cannot contain anything
+ if (g1.dimension() == 0) return false;
+
+ Predicates pred = new Predicates();
+ return pred.S2_contains(toShapeIndex(g1), toShapeIndex(g2), s2Options());
+ }
+
/** Return EWKT for geography object */
public static String asEWKT(Geography geography) {
return geography.toEWKT();
}
+
+ // ─── Helpers
───────────────────────────────────────────────────────────────
+
+ private static Geometry toJTS(Geography g) {
+ if (g instanceof WKBGeography) return ((WKBGeography) g).getJTSGeometry();
+ return Constructors.geogToGeometry(g);
+ }
+
+ private static ShapeIndexGeography toShapeIndex(Geography g) {
+ if (g instanceof WKBGeography) {
+ return ((WKBGeography) g).getShapeIndexGeography();
+ }
+ return new ShapeIndexGeography(g);
+ }
+
+ private static S2BooleanOperation.Options s2Options() {
+ return new S2BooleanOperation.Options();
+ }
+
+ /** Mean Earth radius in meters (WGS84 mean radius). */
+ private static final double EARTH_RADIUS_METERS = 6371008.8;
Review Comment:
There is another place in Sedona codebase (Distance Spheroid / Sphere) also
hard code the value of earth radius. can you unify them together?
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