[SEDONA-631] Add ST_Expand (#1527)

* feat: add ST_Expand

* fix: snowflake tests

* fix: simplify the implementation, remove BBox implementation

* chore: undo changes in BBox

* docs: add additional behavior details

* add test to check preservation of SRID

common/src/main/java/org/apache/sedona/common/Functions.java

@@ -25,6 +25,7 @@
 import com.uber.h3core.exceptions.H3Exception;
 import com.uber.h3core.util.LatLng;
 import java.util.*;
+import java.util.List;
 import java.util.stream.Collectors;
 import org.apache.commons.lang3.tuple.Pair;
 import org.apache.sedona.common.geometryObjects.Circle;
@@ -37,6 +38,8 @@
 import org.locationtech.jts.algorithm.construct.MaximumInscribedCircle;
 import org.locationtech.jts.algorithm.hull.ConcaveHull;
 import org.locationtech.jts.geom.*;
+import org.locationtech.jts.geom.Point;
+import org.locationtech.jts.geom.Polygon;
 import org.locationtech.jts.geom.util.AffineTransformation;
 import org.locationtech.jts.geom.util.GeometryFixer;
 import org.locationtech.jts.io.ByteOrderValues;
@@ -90,6 +93,57 @@ public static Geometry boundary(Geometry geometry) {
     return boundary;
   }
 
+  public static Geometry expand(Geometry geometry, double uniformDelta) {
+    return expand(geometry, uniformDelta, uniformDelta, uniformDelta);
+  }
+
+  public static Geometry expand(Geometry geometry, double deltaX, double deltaY) {
+    return expand(geometry, deltaX, deltaY, 0);
+  }
+
+  public static Geometry expand(Geometry geometry, double deltaX, double deltaY, double deltaZ) {
+    if (geometry == null || geometry.isEmpty()) {
+      return geometry;
+    }
+
+    Coordinate[] coordinates = geometry.getCoordinates();
+    double minX = Double.MAX_VALUE;
+    double maxX = -Double.MAX_VALUE;
+    double minY = Double.MAX_VALUE;
+    double maxY = -Double.MAX_VALUE;
+    double minZ = Double.MAX_VALUE;
+    double maxZ = -Double.MAX_VALUE;
+
+    for (int i = 0; i < coordinates.length; i++) {
+      minX = Math.min(minX, coordinates[i].x);
+      maxX = Math.max(maxX, coordinates[i].x);
+      minY = Math.min(minY, coordinates[i].y);
+      maxY = Math.max(maxY, coordinates[i].y);
+      minZ = Math.min(minZ, coordinates[i].z);
+      maxZ = Math.max(maxZ, coordinates[i].z);
+    }
+
+    minX = minX - deltaX;
+    maxX = maxX + deltaX;
+    minY = minY - deltaY;
+    maxY = maxY + deltaY;
+
+    if (Functions.hasZ(geometry)) {
+      minZ = minZ - deltaZ;
+      maxZ = maxZ + deltaZ;
+      Coordinate[] newCoords = new Coordinate[5];
+      newCoords[0] = new Coordinate(minX, minY, minZ);
+      newCoords[1] = new Coordinate(minX, maxY, minZ);
+      newCoords[2] = new Coordinate(maxX, maxY, maxZ);
+      newCoords[3] = new Coordinate(maxX, minY, maxZ);
+      newCoords[4] = newCoords[0];
+      return geometry.getFactory().createPolygon(newCoords);
+    }
+    Geometry result = Constructors.polygonFromEnvelope(minX, minY, maxX, maxY);
+    result.setSRID(geometry.getSRID());
+    return result;
+  }
+
   public static Geometry buffer(Geometry geometry, double radius) {
     return buffer(geometry, radius, false, "");
   }

common/src/test/java/org/apache/sedona/common/FunctionsTest.java

@@ -2250,6 +2250,64 @@ public void nRingsMultiPolygonMixed() throws Exception {
     assertEquals(expected, actual);
   }
 
+  @Test
+  public void testExpand() throws ParseException {
+    Geometry geometry =
+        GEOMETRY_FACTORY.createPolygon(coordArray(50, 50, 50, 80, 80, 80, 80, 50, 50, 50));
+    String actual = Functions.asWKT(Functions.expand(geometry, 10, 0));
+    String expected = "POLYGON ((40 50, 40 80, 90 80, 90 50, 40 50))";
+    assertEquals(expected, actual);
+
+    geometry = Constructors.geomFromWKT("POINT (10 20 1)", 4326);
+    Geometry result = Functions.expand(geometry, 10);
+    actual = Functions.asWKT(result);
+    expected = "POLYGON Z((0 10 -9, 0 30 -9, 20 30 11, 20 10 11, 0 10 -9))";
+    assertEquals(expected, actual);
+    assertEquals(4326, result.getSRID());
+
+    geometry = Constructors.geomFromWKT("LINESTRING (0 0, 1 1, 2 2)", 0);
+    actual = Functions.asWKT(Functions.expand(geometry, 10, 10));
+    expected = "POLYGON ((-10 -10, -10 12, 12 12, 12 -10, -10 -10))";
+    assertEquals(expected, actual);
+
+    geometry =
+        Constructors.geomFromWKT(
+            "MULTIPOLYGON (((52 68 1, 42 64 1, 66 62 2, 88 64 2, 85 68 2, 72 70 1, 52 68 1)), ((50 50 2, 50 80 2, 80 80 3, 80 50 2, 50 50 2)))",
+            4326);
+    actual = Functions.asWKT(Functions.expand(geometry, 10.5, 2, 5));
+    expected = "POLYGON Z((31.5 48 -4, 31.5 82 -4, 98.5 82 8, 98.5 48 8, 31.5 48 -4))";
+    assertEquals(expected, actual);
+
+    geometry = Constructors.geomFromWKT("MULTIPOINT((10 20 1), (20 30 2))", 0);
+    actual = Functions.asWKT(Functions.expand(geometry, 9.5, 3.5));
+    expected = "POLYGON Z((0.5 16.5 1, 0.5 33.5 1, 29.5 33.5 2, 29.5 16.5 2, 0.5 16.5 1))";
+    assertEquals(expected, actual);
+
+    geometry =
+        Constructors.geomFromWKT(
+            "MULTILINESTRING ((1 0 4, 2 0 4, 4 0 4),(1 0 4, 2 0 4, 4 0 4))", 0);
+    actual = Functions.asWKT(Functions.expand(geometry, 0));
+    expected = "POLYGON Z((1 0 4, 1 0 4, 4 0 4, 4 0 4, 1 0 4))";
+    assertEquals(expected, actual);
+
+    geometry =
+        Constructors.geomFromWKT(
+            "GEOMETRYCOLLECTION (POINT (10 10),LINESTRING (20 20, 30 30),POLYGON ((25 25, 35 35, 35 35, 25 25)),MULTIPOINT (30 30, 40 40),MULTILINESTRING ((40 40, 50 50), (45 45, 55 55)),MULTIPOLYGON (((50 50, 60 60, 60 60, 50 50)), ((55 55, 65 65, 65 65, 55 55))))",
+            1234);
+    result = Functions.expand(geometry, 10);
+    actual = Functions.asWKT(result);
+    expected = "POLYGON ((0 0, 0 75, 75 75, 75 0, 0 0))";
+    assertEquals(expected, actual);
+    assertEquals(1234, result.getSRID());
+
+    // The function drops the M dimension
+    geometry =
+        Constructors.geomFromWKT("POLYGON M((50 50 1, 50 80 2, 80 80 3, 80 50 2, 50 50 1))", 0);
+    actual = Functions.asWKT(Functions.expand(geometry, 0));
+    expected = "POLYGON ((50 50, 50 80, 80 80, 80 50, 50 50))";
+    assertEquals(expected, actual);
+  }
+
   @Test
   public void testBuffer() {
     Polygon polygon =

docs/api/flink/Function.md

@@ -1211,6 +1211,45 @@ Output:
 POLYGON ((0 0, 0 3, 1 3, 1 0, 0 0))
 ```
 
+## ST_Expand
+
+Introduction: Returns a geometry expanded from the bounding box of the input. The expansion can be specified in two ways:
+
+1. By individual axis using `deltaX`, `deltaY`, or `deltaZ` parameters.
+2. Uniformly across all axes using the `uniformDelta` parameter.
+
+!!!Note
+    Things to consider when using this function:
+
+    1. The `uniformDelta` parameter expands Z dimensions for XYZ geometries; otherwise, it only affects XY dimensions.
+    2. For XYZ geometries, specifying only `deltaX` and `deltaY` will preserve the original Z dimension.
+    3. If the input geometry has an M dimension then using this function will drop the said M dimension.
+
+Format:
+
+`ST_Expand(geometry: Geometry, uniformDelta: Double)`
+
+`ST_Expand(geometry: Geometry, deltaX: Double, deltaY: Double)`
+
+`ST_Expand(geometry: Geometry, deltaX: Double, deltaY: Double, deltaZ: Double)`
+
+Since: `v1.6.1`
+
+SQL Example:
+
+```sql
+SELECT ST_Expand(
+        ST_GeomFromWKT('POLYGON Z((50 50 1, 50 80 2, 80 80 3, 80 50 2, 50 50 1))'),
+        10
+   )
+```
+
+Output:
+
+```
+POLYGON Z((40 40 -9, 40 90 -9, 90 90 13, 90 40 13, 40 40 -9))
+```
+
 ## ST_ExteriorRing
 
 Introduction: Returns a LINESTRING representing the exterior ring (shell) of a POLYGON. Returns NULL if the geometry is not a polygon.

docs/api/snowflake/vector-data/Function.md

@@ -933,6 +933,43 @@ SELECT ST_Envelope(polygondf.countyshape)
 FROM polygondf
 ```
 
+## ST_Expand
+
+Introduction: Returns a geometry expanded from the bounding box of the input. The expansion can be specified in two ways:
+
+1. By individual axis using `deltaX`, `deltaY`, or `deltaZ` parameters.
+2. Uniformly across all axes using the `uniformDelta` parameter.
+
+Format:
+
+`ST_Expand(geometry: Geometry, uniformDelta: Double)`
+
+`ST_Expand(geometry: Geometry, deltaX: Double, deltaY: Double)`
+
+`ST_Expand(geometry: Geometry, deltaX: Double, deltaY: Double, deltaZ: Double)`
+
+!!!Note
+    Things to consider when using this function:
+
+    1. The `uniformDelta` parameter expands Z dimensions for XYZ geometries; otherwise, it only affects XY dimensions.
+    2. For XYZ geometries, specifying only `deltaX` and `deltaY` will preserve the original Z dimension.
+    3. If the input geometry has an M dimension then using this function will drop the said M dimension.
+
+SQL Example:
+
+```sql
+SELECT ST_Expand(
+        ST_GeomFromWKT('POLYGON Z((50 50 1, 50 80 2, 80 80 3, 80 50 2, 50 50 1))'),
+        10
+   )
+```
+
+Output:
+
+```
+POLYGON Z((40 40 -9, 40 90 -9, 90 90 13, 90 40 13, 40 40 -9))
+```
+
 ## ST_ExteriorRing
 
 Introduction: Returns a line string representing the exterior ring of the POLYGON geometry. Return NULL if the geometry is not a polygon.

docs/api/sql/Function.md

@@ -1216,6 +1216,45 @@ Output:
 POLYGON ((0 0, 0 3, 1 3, 1 0, 0 0))
 ```
 
+## ST_Expand
+
+Introduction: Returns a geometry expanded from the bounding box of the input. The expansion can be specified in two ways:
+
+1. By individual axis using `deltaX`, `deltaY`, or `deltaZ` parameters.
+2. Uniformly across all axes using the `uniformDelta` parameter.
+
+!!!Note
+    Things to consider when using this function:
+
+    1. The `uniformDelta` parameter expands Z dimensions for XYZ geometries; otherwise, it only affects XY dimensions.
+    2. For XYZ geometries, specifying only `deltaX` and `deltaY` will preserve the original Z dimension.
+    3. If the input geometry has an M dimension then using this function will drop the said M dimension.
+
+Format:
+
+`ST_Expand(geometry: Geometry, uniformDelta: Double)`
+
+`ST_Expand(geometry: Geometry, deltaX: Double, deltaY: Double)`
+
+`ST_Expand(geometry: Geometry, deltaX: Double, deltaY: Double, deltaZ: Double)`
+
+Since: `v1.6.1`
+
+SQL Example:
+
+```sql
+SELECT ST_Expand(
+        ST_GeomFromWKT('POLYGON Z((50 50 1, 50 80 2, 80 80 3, 80 50 2, 50 50 1))'),
+        10
+   )
+```
+
+Output:
+
+```
+POLYGON Z((40 40 -9, 40 90 -9, 90 90 13, 90 40 13, 40 40 -9))
+```
+
 ## ST_ExteriorRing
 
 Introduction: Returns a line string representing the exterior ring of the POLYGON geometry. Return NULL if the geometry is not a polygon.

flink/src/main/java/org/apache/sedona/flink/Catalog.java

@@ -70,6 +70,7 @@ public static UserDefinedFunction[] getFuncs() {
       new Functions.ST_ConcaveHull(),
       new Functions.ST_ConvexHull(),
       new Functions.ST_CrossesDateLine(),
+      new Functions.ST_Expand(),
       new Functions.ST_Envelope(),
       new Functions.ST_Difference(),
       new Functions.ST_Dimension(),

flink/src/main/java/org/apache/sedona/flink/expressions/Functions.java

@@ -244,6 +244,35 @@ public Geometry eval(
     }
   }
 
+  public static class ST_Expand extends ScalarFunction {
+    @DataTypeHint(value = "RAW", bridgedTo = org.locationtech.jts.geom.Geometry.class)
+    public Geometry eval(
+        @DataTypeHint(value = "RAW", bridgedTo = org.locationtech.jts.geom.Geometry.class) Object o,
+        @DataTypeHint(value = "Double") Double uniformDelta) {
+      Geometry geom = (Geometry) o;
+      return org.apache.sedona.common.Functions.expand(geom, uniformDelta);
+    }
+
+    @DataTypeHint(value = "RAW", bridgedTo = org.locationtech.jts.geom.Geometry.class)
+    public Geometry eval(
+        @DataTypeHint(value = "RAW", bridgedTo = org.locationtech.jts.geom.Geometry.class) Object o,
+        @DataTypeHint(value = "Double") Double deltaX,
+        @DataTypeHint(value = "Double") Double deltaY) {
+      Geometry geom = (Geometry) o;
+      return org.apache.sedona.common.Functions.expand(geom, deltaX, deltaY);
+    }
+
+    @DataTypeHint(value = "RAW", bridgedTo = org.locationtech.jts.geom.Geometry.class)
+    public Geometry eval(
+        @DataTypeHint(value = "RAW", bridgedTo = org.locationtech.jts.geom.Geometry.class) Object o,
+        @DataTypeHint(value = "Double") Double deltaX,
+        @DataTypeHint(value = "Double") Double deltaY,
+        @DataTypeHint(value = "Double") Double deltaZ) {
+      Geometry geom = (Geometry) o;
+      return org.apache.sedona.common.Functions.expand(geom, deltaX, deltaY, deltaZ);
+    }
+  }
+
   public static class ST_Dimension extends ScalarFunction {
     @DataTypeHint("Integer")
     public Integer eval(

flink/src/test/java/org/apache/sedona/flink/FunctionTest.java

@@ -379,6 +379,45 @@ public void testEnvelope() {
         first(linestringTable).getField(0).toString());
   }
 
+  @Test
+  public void testExpand() {
+    Table baseTable =
+        tableEnv.sqlQuery(
+            "SELECT ST_GeomFromWKT('POLYGON ((50 50 1, 50 80 2, 80 80 3, 80 50 2, 50 50 1))') as geom");
+    String actual =
+        (String)
+            first(
+                    baseTable
+                        .select(call(Functions.ST_Expand.class, $("geom"), 10))
+                        .as("geom")
+                        .select(call(Functions.ST_AsText.class, $("geom"))))
+                .getField(0);
+    String expected = "POLYGON Z((40 40 -9, 40 90 -9, 90 90 13, 90 40 13, 40 40 -9))";
+    assertEquals(expected, actual);
+
+    actual =
+        (String)
+            first(
+                    baseTable
+                        .select(call(Functions.ST_Expand.class, $("geom"), 5, 6))
+                        .as("geom")
+                        .select(call(Functions.ST_AsText.class, $("geom"))))
+                .getField(0);
+    expected = "POLYGON Z((45 44 1, 45 86 1, 85 86 3, 85 44 3, 45 44 1))";
+    assertEquals(expected, actual);
+
+    actual =
+        (String)
+            first(
+                    baseTable
+                        .select(call(Functions.ST_Expand.class, $("geom"), 6, 5, -3))
+                        .as("geom")
+                        .select(call(Functions.ST_AsText.class, $("geom"))))
+                .getField(0);
+    expected = "POLYGON Z((44 45 4, 44 85 4, 86 85 0, 86 45 0, 44 45 4))";
+    assertEquals(expected, actual);
+  }
+
   @Test
   public void testFlipCoordinates() {
     Table pointTable = createPointTable_real(testDataSize);

python/sedona/sql/st_functions.py

@@ -511,6 +511,31 @@ def ST_Envelope(geometry: ColumnOrName) -> Column:
     return _call_st_function("ST_Envelope", geometry)
 
 
+@validate_argument_types
+def ST_Expand(geometry: ColumnOrName, deltaX_uniformDelta: Union[ColumnOrName, float], deltaY: Optional[Union[ColumnOrName, float]] = None, deltaZ: Optional[Union[ColumnOrName, float]] = None) -> Column:
+    """Expand the given geometry column by a constant unit in each direction
+
+    :param geometry: Geometry column to calculate the envelope of.
+    :type geometry: ColumnOrName
+    :param deltaX_uniformDelta: it is either deltaX or uniformDelta depending on the number of arguments provided
+    :type deltaX_uniformDelta: Union[ColumnOrName, float]
+    :param deltaY: Constant unit of deltaY
+    :type deltaY: Union[ColumnOrName, float]
+    :param deltaZ: Constant unit of deltaZ
+    :type deltaZ: Union[ColumnOrName, float]
+    :return: Envelope of geometry as a geometry column.
+    :rtype: Column
+    """
+    if deltaZ is None:
+        args = (geometry, deltaX_uniformDelta, deltaY)
+        if deltaY is None:
+            args = (geometry, deltaX_uniformDelta)
+    else:
+        args = (geometry, deltaX_uniformDelta, deltaY, deltaZ)
+
+    return _call_st_function("ST_Expand", args)
+
+
 @validate_argument_types
 def ST_ExteriorRing(polygon: ColumnOrName) -> Column:
     """Get a linestring representing the exterior ring of a polygon geometry