iGN5117 commented on code in PR #877:
URL: https://github.com/apache/sedona/pull/877#discussion_r1248087645
##########
docs/api/sql/Function.md:
##########
@@ -381,6 +381,32 @@ SELECT ST_Centroid(polygondf.countyshape)
FROM polygondf
```
+## ST_ClosestPoint
+
+Introduction: Returns the 2-dimensional point on geom1 that is closest to
geom2. This is the first point of the shortest line between the geometries. If
using 3D geometries, the Z coordinates will be ignored. If you have a 3D
Geometry, you may prefer to use ST_3DClosestPoint.
+
Review Comment:
Update documentation here to include the thrown exception if any of the
geometry is empty
##########
common/src/test/java/org/apache/sedona/common/FunctionsTest.java:
##########
@@ -1200,6 +1199,74 @@ public void geometryTypeWithMeasuredCollection() {
assertEquals(expected4, actual4);
}
+ @Test
+ public void closestPoint() {
+ Point point1 = GEOMETRY_FACTORY.createPoint(new Coordinate(1, 1));
+ LineString lineString1 =
GEOMETRY_FACTORY.createLineString(coordArray(1, 0, 1, 1, 2, 1, 2, 0, 1, 0));
+ String expected1 = "POINT (1 1)";
+ String actual1 = Functions.closestPoint(point1, lineString1).toText();
+ assertEquals(expected1, actual1);
+
+ Point point2 = GEOMETRY_FACTORY.createPoint(new Coordinate(160, 40));
+ LineString lineString2 =
GEOMETRY_FACTORY.createLineString(coordArray(10, 30, 50, 50, 30, 110, 70, 90,
180, 140, 130, 190));
+ String expected2 = "POINT (160 40)";
+ String actual2 = Functions.closestPoint(point2, lineString2).toText();
+ assertEquals(expected2, actual2);
+ Point expectedPoint3 = GEOMETRY_FACTORY.createPoint(new
Coordinate(125.75342465753425, 115.34246575342466));
+ Double expected3 = Functions.closestPoint(lineString2,
point2).distance(expectedPoint3);
+ assertEquals(expected3, 0, 1e-6);
+
+ Point point4 = GEOMETRY_FACTORY.createPoint(new Coordinate(80, 160));
+ Polygon polygonA = GEOMETRY_FACTORY.createPolygon(coordArray(190, 150,
20, 10, 160, 70, 190, 150));
+ Geometry polygonB = Functions.buffer(point4, 30);
+ Point expectedPoint4 = GEOMETRY_FACTORY.createPoint(new
Coordinate(131.59149149528952, 101.89887534906197));
+ Double expected4 = Functions.closestPoint(polygonA,
polygonB).distance(expectedPoint4);
+ assertEquals(expected4, 0, 1e-6);
+ }
+
+ @Test
+ public void closestPoint3d() {
+ // One of the object is 3D
+ Point point1 = GEOMETRY_FACTORY.createPoint(new Coordinate(1,
1,10000));
+ LineString lineString1 =
GEOMETRY_FACTORY.createLineString(coordArray(1, 0, 1, 1, 2, 1, 2, 0, 1, 0));
+ String expected1 = "POINT (1 1)";
+ String actual1 = Functions.closestPoint(point1, lineString1).toText();
+ assertEquals(expected1, actual1);
+
+ // Both of the object are 3D
+ LineString lineString3D =
GEOMETRY_FACTORY.createLineString(coordArray3d(1, 0, 100, 1, 1, 20, 2, 1, 40,
2, 0, 60, 1, 0, 70));
+ String expected2 = "POINT (1 1)";
+ String actual2 = Functions.closestPoint(point1, lineString3D).toText();
+ assertEquals(expected2, actual2);
+ }
+
+ @Test
+ public void closestPointGeomtryCollection() {
+ LineString line = GEOMETRY_FACTORY.createLineString(coordArray(2, 0,
0, 2));
+ Geometry[] geometry = new Geometry[] {
+ GEOMETRY_FACTORY.createLineString(coordArray(2, 0, 2, 1)),
+ GEOMETRY_FACTORY.createPolygon(coordArray(0.0, 0.0, 1.0, 1.0,
1.0, 0.0, 0.0, 0.0))
+ };
+ GeometryCollection geometryCollection =
GEOMETRY_FACTORY.createGeometryCollection(geometry);
+ String actual1 = Functions.closestPoint(line,
geometryCollection).toText();
+ String expected1 = "POINT (2 0)";
+ assertEquals(actual1 ,expected1);
+ }
+
+ @Test
+ public void closestPointEmpty() {
+ // One of the object is empty
+ Point point = GEOMETRY_FACTORY.createPoint(new Coordinate(1, 1));
+ LineString emptyLineString = GEOMETRY_FACTORY.createLineString();
+ Geometry actual = Functions.closestPoint(point, emptyLineString);
+ assertNull(actual);
+
+ // Both objects are empty
+ Polygon emptyPolygon = GEOMETRY_FACTORY.createPolygon();
Review Comment:
refactor these test cases to catch the meaningful exception.
There would be 2 asserts, 1 for the type of exception thrown, 1 for the
message in the exception.
Check implementation and tests of nRings for reference
##########
common/src/test/java/org/apache/sedona/common/FunctionsTest.java:
##########
@@ -1200,6 +1199,31 @@ public void geometryTypeWithMeasuredCollection() {
assertEquals(expected4, actual4);
}
+ @Test
+ public void closestPoint() {
+ Point point1 = GEOMETRY_FACTORY.createPoint(new Coordinate(1, 1));
+ LineString lineString1 =
GEOMETRY_FACTORY.createLineString(coordArray(1, 0, 1, 1, 2, 1, 2, 0, 1, 0));
+ String expected1 = "POINT (1 1)";
+ String actual1 = Functions.closestPoint(point1, lineString1).toText();
+ assertEquals(expected1, actual1);
+
+ Point point2 = GEOMETRY_FACTORY.createPoint(new Coordinate(160, 40));
+ LineString lineString2 =
GEOMETRY_FACTORY.createLineString(coordArray(10, 30, 50, 50, 30, 110, 70, 90,
180, 140, 130, 190));
+ String expected2 = "POINT (160 40)";
+ String actual2 = Functions.closestPoint(point2, lineString2).toText();
+ assertEquals(expected2, actual2);
+ Point expectedPoint3 = GEOMETRY_FACTORY.createPoint(new
Coordinate(125.75342465753425, 115.34246575342466));
+ Double expected3 = Functions.closestPoint(lineString2,
point2).distance(expectedPoint3);
+ assertEquals(expected3, 0, 1e-3);
+
+ Point point4 = GEOMETRY_FACTORY.createPoint(new Coordinate(80, 160));
+ Polygon polygonA = GEOMETRY_FACTORY.createPolygon(coordArray(190, 150,
20, 10, 160, 70, 190, 150));
+ Geometry polygonB = Functions.buffer(point4, 30);
+ Point expectedPoint4 = GEOMETRY_FACTORY.createPoint(new
Coordinate(131.59149149528952, 101.89887534906197));
+ Double expected4 = Functions.closestPoint(polygonA,
polygonB).distance(expectedPoint4);
+ assertEquals(expected4, 0, 1e-6);
+ }
Review Comment:
There could be many possible use cases. Like given a geometry collection
representing a neighborhood (polygon/multipolygon for houses), find closest
point to a given external point.
##########
docs/api/flink/Function.md:
##########
@@ -363,6 +363,31 @@ Input: `MULTILINESTRING((0 0, 10 0, 10 10, 0 10, 0 0),(10
10, 20 10, 20 20, 10 2
Output: `MULTIPOLYGON(((0 0,0 10,10 10,10 0,0 0)),((10 10,10 20,20 20,20 10,10
10)))`
+## ST_ClosestPoint
+
+Introduction: Returns the 2-dimensional point on geom1 that is closest to
geom2. This is the first point of the shortest line between the geometries.
+
+Format: `ST_ClosestPoint(g1: geomtry, g2: geometry)`
+
+Since: `1.5.0`
+
+Example1:
+```sql
+SELECT ST_AsText( ST_ClosestPoint(g1, g2)) As ptwkt;
Review Comment:
Update documentation here to include the thrown exception if any of the
geometry is empty
##########
common/src/main/java/org/apache/sedona/common/Functions.java:
##########
@@ -447,6 +448,17 @@ public static Geometry lineFromMultiPoint(Geometry
geometry) {
return GEOMETRY_FACTORY.createLineString(coordinates.toArray(new
Coordinate[0]));
}
+ public static Geometry closestPoint(Geometry left, Geometry right) {
+ DistanceOp distanceOp = new DistanceOp(left, right);
+ try {
+ Coordinate[] closestPoints = distanceOp.nearestPoints();
+ return GEOMETRY_FACTORY.createPoint(closestPoints[0]);
+ }
+ catch (Exception e) {
+ return null;
Review Comment:
Do not throw null here, throw a meaningful exception. If this is thrown if
the geometry is empty, throw an IllegalArgumentException with an appropriate
message
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