Add wrappers for Projected CRS and Coordinate Operation.

Test the transform of a point from geographic to projected CRS.

Author: desruisseaux

geoapi/src/main/java/org/locationtech/proj4j/geoapi/AbstractCRS.java

@@ -28,21 +28,20 @@
 
 /**
  * Wraps a PROJ4J implementation behind the equivalent GeoAPI interface.
- * The CRS is assumed two-dimensional.
  *
  * @author Martin Desruisseaux (Geomatys)
  */
 @SuppressWarnings("serial")
 abstract class AbstractCRS extends Wrapper implements SingleCRS, CoordinateSystem, Serializable {
     /**
-     * The number of dimensions of the CRS.
+     * The wrapped PROJ4 implementation.
      */
-    private static final int BIDIMENSIONAL = 2;
+    final org.locationtech.proj4j.CoordinateReferenceSystem impl;
 
     /**
-     * The wrapped PROJ4 implementation.
+     * Whether this CRS is three-dimensional instead of two-dimensional.
      */
-    private final org.locationtech.proj4j.CoordinateReferenceSystem impl;
+    final boolean is3D;
 
     /**
      * The coordinate system axes, computed and cached when first requested.
@@ -55,23 +54,29 @@ abstract class AbstractCRS extends Wrapper implements SingleCRS, CoordinateSyste
     /**
      * Creates a new wrapper for the given PROJ4J implementation.
      */
-    AbstractCRS(final org.locationtech.proj4j.CoordinateReferenceSystem impl) {
+    AbstractCRS(final org.locationtech.proj4j.CoordinateReferenceSystem impl, final boolean is3D) {
         this.impl = impl;
+        this.is3D = is3D;
     }
 
     /**
      * Wraps the given implementation.
      *
      * @param  impl the implementation to wrap, or {@code null}
+     * @param  is3D whether to return a three-dimensional CRS instead of a two-dimensional one
      * @return the wrapper, or {@code null} if the given implementation was null
      */
-    static AbstractCRS wrap(final org.locationtech.proj4j.CoordinateReferenceSystem impl) {
+    static AbstractCRS wrap(final org.locationtech.proj4j.CoordinateReferenceSystem impl, final boolean is3D) {
         if (impl != null) {
             final Projection proj = impl.getProjection();
             if (proj == null || proj.isGeographic()) {
-                return new GeographicCRSWrapper(impl);
+                return new GeographicCRSWrapper(impl, is3D);
             } else {
-                // TODO
+                /*
+                 * TODO: there is a possibility that the PROJ4J `projection` is actually for something
+                 * else than a map projection. But there is apparently no easy way to determine that.
+                 */
+                return new ProjectedCRSWrapper(impl, is3D);
             }
         }
         return null;
@@ -111,11 +116,11 @@ public CoordinateSystem getCoordinateSystem() {
     }
 
     /**
-     * {@return the number of dimensions, which is fixed to 2}.
+     * {@return the number of dimensions, which is 2 or 3}.
      */
     @Override
     public final int getDimension() {
-        return BIDIMENSIONAL;
+        return is3D ? TRIDIMENSIONAL : BIDIMENSIONAL;
     }
 
     /**
@@ -147,7 +152,7 @@ public final CoordinateSystemAxis getAxis(int dimension) {
         Axis[] axes = this.axes;
         if (axes == null) {
             final Axis[] axesForAllDirections = axesForAllDirections();
-            axes = Arrays.copyOfRange(axesForAllDirections, Axis.INDEX_OF_EAST, axesForAllDirections.length);
+            axes = Arrays.copyOfRange(axesForAllDirections, Axis.INDEX_OF_EAST, Axis.INDEX_OF_EAST + getDimension());
             final Projection proj = impl.getProjection();
             if (proj != null) {
                 final AxisOrder order = proj.getAxisOrder();

geoapi/src/main/java/org/locationtech/proj4j/geoapi/GeographicCRSWrapper.java

@@ -21,7 +21,6 @@
 
 /**
  * Wraps a PROJ4J implementation behind the equivalent GeoAPI interface.
- * The CRS is assumed two-dimensional.
  *
  * @author Martin Desruisseaux (Geomatys)
  */
@@ -30,8 +29,8 @@ final class GeographicCRSWrapper extends AbstractCRS implements EllipsoidalCS, G
     /**
      * Creates a new wrapper for the given PROJ4J implementation.
      */
-    GeographicCRSWrapper(final org.locationtech.proj4j.CoordinateReferenceSystem impl) {
-        super(impl);
+    GeographicCRSWrapper(org.locationtech.proj4j.CoordinateReferenceSystem impl, boolean is3D) {
+        super(impl, is3D);
     }
 
     /**

geoapi/src/main/java/org/locationtech/proj4j/geoapi/IdentifierEPSG.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright 2025, PROJ4J contributors
+ *
+ * Licensed 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.locationtech.proj4j.geoapi;
+
+import java.util.Collections;
+import java.util.Set;
+import org.opengis.referencing.ReferenceIdentifier;
+
+
+/**
+ * A simple EPSG identifier made of only a code and a code space.
+ *
+ * @author Martin Desruisseaux (Geomatys)
+ */
+final class IdentifierEPSG extends Wrapper {
+    /**
+     * The EPSG code.
+     */
+    private final int code;
+
+    /**
+     * Creates a new identifier for the given EPSG code.
+     */
+    private IdentifierEPSG(final int code) {
+        this.code = code;
+    }
+
+    /**
+     * Wraps the given EPSG code.
+     *
+     * @param  code the EPSG code, or 0 if none
+     * @return the wrapper, or an empty set if the given EPSG code was 0
+     */
+    static Set<ReferenceIdentifier> wrap(final int code) {
+        return (code != 0) ? Collections.singleton(new IdentifierEPSG(code)) : Collections.emptySet();
+    }
+
+    /**
+     * {@return the EPSG code}.
+     */
+    @Override
+    Object implementation() {
+        return code;
+    }
+
+    /**
+     * {@return the code space, which is fixed to "EPSG"}.
+     */
+    @Override
+    public String getCodeSpace() {
+        return "EPSG";
+    }
+
+    /**
+     * {@return the string representation of the EPSG code}.
+     */
+    @Override
+    public String getCode() {
+        return Integer.toString(code);
+    }
+
+    /**
+     * {@return the string representation of this identifier}.
+     */
+    @Override
+    public String toString() {
+        return getCodeSpace() + ':' + code;
+    }
+}