ayushtkn commented on code in PR #6581:
URL: https://github.com/apache/hive/pull/6581#discussion_r3653186891
##########
ql/src/java/org/apache/hadoop/hive/ql/udf/esri/ST_GeodesicLengthWGS84.java:
##########
@@ -66,37 +70,100 @@ public DoubleWritable evaluate(BytesWritable geomref) {
return null;
}
- OGCGeometry ogcGeometry = GeometryUtils.geometryFromEsriShape(geomref);
- if (ogcGeometry == null) {
+ Geometry geom = GeometryUtils.geometryFromEsriShape(geomref);
+ if (geom == null) {
LogUtils.Log_ArgumentsNull(LOG);
return null;
}
- Geometry esriGeom = ogcGeometry.getEsriGeometry();
- switch (esriGeom.getType()) {
- case Point:
- case MultiPoint:
- resultDouble.set(0.);
- break;
- default:
- MultiPath lines = (MultiPath) (esriGeom);
- int nPath = lines.getPathCount();
- double length = 0.;
- for (int ix = 0; ix < nPath; ix++) {
- int curPt = lines.getPathStart(ix);
- int pastPt = lines.getPathEnd(ix);
- Point fromPt = lines.getPoint(curPt);
- Point toPt = null;
- for (int vx = curPt + 1; vx < pastPt; vx++) {
- toPt = lines.getPoint(vx);
- length += GeometryEngine.geodesicDistanceOnWGS84(fromPt, toPt);
- fromPt = toPt;
+ switch (geom.getGeometryType()) {
+ case "Point", "MultiPoint" -> resultDouble.set(0.0);
+ case "LineString", "LinearRing" ->
resultDouble.set(lineStringLength((LineString) geom));
+ case "MultiLineString" -> {
+ MultiLineString mls = (MultiLineString) geom;
+ double total = 0.0;
+ for (int i = 0; i < mls.getNumGeometries(); i++) {
+ total += lineStringLength((LineString) mls.getGeometryN(i));
}
+ resultDouble.set(total);
}
- resultDouble.set(length);
- break;
+ default -> resultDouble.set(0.0);
}
return resultDouble;
}
+
+ /**
+ * Computes the geodesic length of a single LineString by summing the
ellipsoidal
+ * (WGS84) distances between consecutive vertices. Iterates the
CoordinateSequence
+ * directly to avoid per-vertex Point object allocation.
+ */
+ private static double lineStringLength(LineString line) {
+ CoordinateSequence seq = line.getCoordinateSequence();
+ int nPts = seq.size();
+ if (nPts < 2) {
+ return 0.0;
+ }
+ double length = 0.0;
+ for (int i = 1; i < nPts; i++) {
+ length += vincentyDistanceMeters(
+ seq.getX(i - 1), seq.getY(i - 1),
+ seq.getX(i), seq.getY(i));
+ }
+ return length;
+ }
+
+ /**
+ * Ellipsoidal geodesic distance between two lon/lat points on the WGS84
spheroid,
+ * using Vincenty's inverse formula (the same ellipsoidal model the ESRI
library used,
+ * so results match the previous implementation). Coordinates are in
degrees, result
Review Comment:
Reverted the reimplementation. ST_GeodesicLengthWGS84 delegates to
GeometryEngine.geodesicDistanceOnWGS84.
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