[GH-2610] Integrate proj4sedona for CRS transformation

common/pom.xml

@@ -124,6 +124,11 @@
             <groupId>org.datasyslab</groupId>
             <artifactId>campskeleton</artifactId>
         </dependency>
+        <!-- proj4sedona for CRS transformation (pure Java, no LGPL dependencies) -->
+        <dependency>
+            <groupId>org.datasyslab</groupId>
+            <artifactId>proj4sedona</artifactId>
+        </dependency>
     </dependencies>
     <build>
         <sourceDirectory>src/main/java</sourceDirectory>

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

@@ -264,20 +264,24 @@ public static Geometry lineFromText(String geomString) {
   }
 
   public static Geometry polygonFromEnvelope(double minX, double minY, double maxX, double maxY) {
+    return polygonFromEnvelope(minX, minY, maxX, maxY, GEOMETRY_FACTORY);
+  }
+
+  public static Geometry polygonFromEnvelope(
+      double minX, double minY, double maxX, double maxY, GeometryFactory factory) {
     Coordinate[] coordinates = new Coordinate[5];
     coordinates[0] = new Coordinate(minX, minY);
     coordinates[1] = new Coordinate(minX, maxY);
     coordinates[2] = new Coordinate(maxX, maxY);
     coordinates[3] = new Coordinate(maxX, minY);
     coordinates[4] = coordinates[0];
-    return GEOMETRY_FACTORY.createPolygon(coordinates);
+    return factory.createPolygon(coordinates);
   }
 
   public static Geometry makeEnvelope(
       double minX, double minY, double maxX, double maxY, int srid) {
-    Geometry envelope = polygonFromEnvelope(minX, minY, maxX, maxY);
-    envelope.setSRID(srid);
-    return envelope;
+    GeometryFactory geometryFactory = new GeometryFactory(new PrecisionModel(), srid);
+    return polygonFromEnvelope(minX, minY, maxX, maxY, geometryFactory);
   }
 
   public static Geometry makeEnvelope(double minX, double minY, double maxX, double maxY) {
@@ -315,10 +319,6 @@ public static Geometry geomFromMySQL(byte[] binary) throws ParseException {
 
     buffer.get(wkb);
 
-    Geometry geom = geomFromWKB(wkb);
-
-    geom.setSRID(srid);
-
-    return geom;
+    return geomFromWKB(wkb, srid);
   }
 }

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

@@ -270,9 +270,7 @@ public static Geometry expand(Geometry geometry, double deltaX, double deltaY, d
       newCoords[4] = newCoords[0];
       return geometry.getFactory().createPolygon(newCoords);
     }
-    Geometry result = Constructors.polygonFromEnvelope(minX, minY, maxX, maxY);
-    result.setSRID(geometry.getSRID());
-    return result;
+    return Constructors.polygonFromEnvelope(minX, minY, maxX, maxY, geometry.getFactory());
   }
 
   public static Geometry buffer(Geometry geometry, double radius) {

common/src/main/java/org/apache/sedona/common/FunctionsProj4.java

@@ -0,0 +1,194 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.sedona.common;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import org.datasyslab.proj4sedona.core.Proj;
+import org.datasyslab.proj4sedona.jts.JTSGeometryTransformer;
+import org.datasyslab.proj4sedona.parser.CRSSerializer;
+import org.locationtech.jts.geom.Geometry;
+
+/**
+ * CRS transformation functions using proj4sedona library.
+ *
+ * <p>This class provides coordinate reference system (CRS) transformation for vector geometries
+ * using the proj4sedona library, which is a pure Java implementation without LGPL dependencies.
+ *
+ * <h2>Supported CRS Input Formats</h2>
+ *
+ * <ul>
+ *   <li><b>EPSG code</b>: "EPSG:4326", "EPSG:3857"
+ *   <li><b>WKT1</b>: OGC Well-Known Text format (PROJCS[...] or GEOGCS[...])
+ *   <li><b>WKT2</b>: ISO 19162:2019 format (PROJCRS[...] or GEOGCRS[...])
+ *   <li><b>PROJ string</b>: "+proj=longlat +datum=WGS84 +no_defs"
+ *   <li><b>PROJJSON</b>: JSON representation of CRS ({"type": "GeographicCRS", ...})
+ * </ul>
+ *
+ * <h2>NAD Grid Support</h2>
+ *
+ * <p>NAD grid files can be specified in PROJ strings using the +nadgrids parameter:
+ *
+ * <ul>
+ *   <li><b>Local file</b>: "+nadgrids=/path/to/grid.gsb"
+ *   <li><b>PROJ CDN</b>: "+nadgrids=@us_noaa_conus.tif" (@ prefix means optional)
+ *   <li><b>HTTPS URL</b>: "+nadgrids=https://cdn.proj.org/us_noaa_conus.tif"
+ * </ul>
+ *
+ * <p>Grid files with @ prefix are optional - if not found, the transformation continues without the
+ * grid. Without @ prefix, the grid is mandatory and an error is thrown if not found.
+ *
+ * @since 1.9.0
+ */
+public class FunctionsProj4 {
+
+  /** Pattern to match EPSG codes (e.g., "EPSG:4326", "epsg:2154") */
+  private static final Pattern EPSG_PATTERN =
+      Pattern.compile("^EPSG:(\\d+)$", Pattern.CASE_INSENSITIVE);
+
+  /**
+   * Transform a geometry from the source CRS specified by the geometry's SRID to the target CRS.
+   *
+   * @param geometry The geometry to transform
+   * @param targetCRS Target CRS definition (EPSG code, WKT, PROJ string, or PROJJSON)
+   * @return The transformed geometry with SRID set to the target CRS EPSG code (if identifiable)
+   * @throws IllegalArgumentException if source CRS cannot be determined from geometry SRID
+   */
+  public static Geometry transform(Geometry geometry, String targetCRS) {
+    return transform(geometry, null, targetCRS);
+  }
+
+  /**
+   * Transform a geometry from one CRS to another with lenient parameter.
+   *
+   * <p><b>Note:</b> The {@code lenient} parameter is accepted for API compatibility with GeoTools
+   * but is ignored. proj4sedona always performs strict transformation.
+   *
+   * @param geometry The geometry to transform
+   * @param sourceCRS Source CRS definition (EPSG code, WKT, PROJ string, or PROJJSON), or null to
+   *     use geometry's SRID
+   * @param targetCRS Target CRS definition (EPSG code, WKT, PROJ string, or PROJJSON)
+   * @param lenient Ignored parameter, kept for API compatibility
+   * @return The transformed geometry with SRID set to the target CRS EPSG code (if identifiable)
+   * @throws IllegalArgumentException if source CRS is null and geometry has no SRID
+   */
+  public static Geometry transform(
+      Geometry geometry, String sourceCRS, String targetCRS, boolean lenient) {
+    // lenient parameter is ignored - proj4sedona doesn't support it
+    return transform(geometry, sourceCRS, targetCRS);
+  }
+
+  /**
+   * Transform a geometry from one CRS to another.
+   *
+   * @param geometry The geometry to transform
+   * @param sourceCRS Source CRS definition (EPSG code, WKT, PROJ string, or PROJJSON), or null to
+   *     use geometry's SRID
+   * @param targetCRS Target CRS definition (EPSG code, WKT, PROJ string, or PROJJSON)
+   * @return The transformed geometry with SRID set to the target CRS EPSG code (if identifiable)
+   * @throws IllegalArgumentException if source CRS is null and geometry has no SRID
+   */
+  public static Geometry transform(Geometry geometry, String sourceCRS, String targetCRS) {
+    if (geometry == null) {
+      return null;
+    }
+
+    // Determine source CRS
+    String effectiveSourceCRS = sourceCRS;
+    if (effectiveSourceCRS == null || effectiveSourceCRS.isEmpty()) {
+      int srid = geometry.getSRID();
+      if (srid != 0) {
+        effectiveSourceCRS = "EPSG:" + srid;
+      } else {
+        throw new IllegalArgumentException(
+            "Source CRS must be specified. No SRID found on geometry.");
+      }
+    }
+
+    // Check if source and target are the same EPSG code
+    Integer sourceSRID = extractEpsgCode(effectiveSourceCRS);
+    Integer targetSRID = extractEpsgCode(targetCRS);
+
+    if (sourceSRID != null && sourceSRID.equals(targetSRID)) {
+      // Same CRS, just update SRID if needed
+      if (geometry.getSRID() != targetSRID) {
+        Geometry result = geometry.copy();
+        result = Functions.setSRID(result, targetSRID);
+        result.setUserData(geometry.getUserData());
+        return result;
+      }
+      return geometry;
+    }
+
+    // Perform transformation using cached projections to avoid per-row overhead.
+    // JTSGeometryTransformer.cached() uses Proj4.cachedConverter() internally,
+    // which caches parsed Proj objects for repeated transformations.
+    JTSGeometryTransformer transformer =
+        JTSGeometryTransformer.cached(effectiveSourceCRS, targetCRS);
+    Geometry transformed = transformer.transform(geometry);
+
+    // Set SRID on result
+    if (targetSRID == null) {
+      try {
+        Proj targetProj = new Proj(targetCRS);
+        String epsgCode = CRSSerializer.toEpsgCode(targetProj);
+        if (epsgCode != null) {
+          Integer epsg = extractEpsgCode(epsgCode);
+          if (epsg != null) {
+            targetSRID = epsg;
+          }
+        }
+      } catch (Exception e) {
+        // Could not identify EPSG code, leave SRID as 0
+      }
+    }
+
+    if (targetSRID == null) {
+      targetSRID = 0;
+    }
+    transformed = Functions.setSRID(transformed, targetSRID);
+
+    // Preserve user data
+    transformed.setUserData(geometry.getUserData());
+
+    return transformed;
+  }
+
+  /**
+   * Extract EPSG code from a CRS string if it's in EPSG format.
+   *
+   * @param crs CRS string (may be EPSG code, WKT, PROJ string, etc.)
+   * @return EPSG code as integer, or null if not an EPSG code format
+   */
+  private static Integer extractEpsgCode(String crs) {
+    if (crs == null || crs.isEmpty()) {
+      return null;
+    }
+
+    Matcher matcher = EPSG_PATTERN.matcher(crs.trim());
+    if (matcher.matches()) {
+      try {
+        return Integer.parseInt(matcher.group(1));
+      } catch (NumberFormatException e) {
+        return null;
+      }
+    }
+    return null;
+  }
+}