Add two new functions ST_LineInterpolatePoint and ST_LineSubstring

docs/CHANGELOG.md

@@ -7,3 +7,5 @@
 + Add ST_ConcaveHull function
 + Improve ST_Graph function to keep a list of columns for the edges
 + Upgrade H2 database from 2.1.214 to 2.2.220
++ Add ST_LineSubstring and ST_LineInterpolatePoint functions
+

h2gis-functions/src/main/java/org/h2gis/functions/factory/H2GISFunctions.java

@@ -62,6 +62,8 @@
 import org.h2gis.functions.spatial.generalize.ST_PrecisionReducer;
 import org.h2gis.functions.spatial.generalize.ST_Simplify;
 import org.h2gis.functions.spatial.generalize.ST_SimplifyPreserveTopology;
+import org.h2gis.functions.spatial.linear_referencing.ST_LineInterpolatePoint;
+import org.h2gis.functions.spatial.linear_referencing.ST_LineSubstring;
 import org.h2gis.functions.spatial.mesh.ST_ConstrainedDelaunay;
 import org.h2gis.functions.spatial.mesh.ST_Delaunay;
 import org.h2gis.functions.spatial.mesh.ST_Tessellate;
@@ -320,7 +322,9 @@ public static Function[] getBuiltInsFunctions() {
                 new ST_MemSize(),
                 new ST_Multi(),
                 new ST_AsEWKB(),
-                new ST_ConcaveHull()
+                new ST_ConcaveHull(),
+                new ST_LineSubstring(),
+                new ST_LineInterpolatePoint()
         };
     }
 

h2gis-functions/src/main/java/org/h2gis/functions/spatial/linear_referencing/ST_LineInterpolatePoint.java

@@ -0,0 +1,83 @@
+/**
+ * H2GIS is a library that brings spatial support to the H2 Database Engine
+ * <a href="http://www.h2database.com">http://www.h2database.com</a>. H2GIS is developed by CNRS
+ * <a href="http://www.cnrs.fr/">http://www.cnrs.fr/</a>.
+ *
+ * This code is part of the H2GIS project. H2GIS is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU
+ * Lesser General Public License as published by the Free Software Foundation;
+ * version 3.0 of the License.
+ *
+ * H2GIS is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
+ * for more details <http://www.gnu.org/licenses/>.
+ *
+ *
+ * For more information, please consult: <a href="http://www.h2gis.org/">http://www.h2gis.org/</a>
+ * or contact directly: info_at_h2gis.org
+ */
+package org.h2gis.functions.spatial.linear_referencing;
+
+import org.h2gis.api.DeterministicScalarFunction;
+import org.locationtech.jts.geom.Coordinate;
+import org.locationtech.jts.geom.Geometry;
+import org.locationtech.jts.geom.LineString;
+import org.locationtech.jts.geom.MultiLineString;
+import org.locationtech.jts.linearref.LengthIndexedLine;
+
+import java.sql.SQLException;
+import java.util.ArrayList;
+
+/**
+ *  Returns a point interpolate along the input LineString or MultiLineString starting at the given fraction.
+ *  @author  Erwan Bocher, CNRS (2023)
+ */
+public class ST_LineInterpolatePoint extends DeterministicScalarFunction {
+
+    public ST_LineInterpolatePoint(){
+        addProperty(PROP_REMARKS, "Returns a point interpolate along the input LineString or MultiLineString starting at the given fraction.");
+    }
+
+    @Override
+    public String getJavaStaticMethod() {
+        return "execute";
+    }
+
+    /**
+     * Returns a point interpolate along the input LineString or MultiLineString starting at the given fractions.
+     * @param geometry the input lines
+     * @param start the start fraction between 0 and 1
+     * @return single or multiparts lines
+     * @throws SQLException
+     */
+    public static Geometry execute(Geometry geometry, double start) throws SQLException {
+        if(geometry==null){
+            return null;
+        }
+        if ( start < 0 || start > 1 ){
+            throw new SQLException("Allowed between 0 and  1");
+        }
+
+        if(geometry.isEmpty()){
+            return geometry;
+        }
+
+        if(geometry instanceof LineString){
+            double length = geometry.getLength();
+            LengthIndexedLine ll = new LengthIndexedLine(geometry);
+            return geometry.getFactory().createPoint(ll.extractPoint(start*length));
+        } else if (geometry instanceof MultiLineString) {
+            int nb = geometry.getNumGeometries();
+            ArrayList<Coordinate> points = new ArrayList<>();
+            for (int i = 0; i < nb; i++) {
+                Geometry line = geometry.getGeometryN(i);
+                double length = line.getLength();
+                LengthIndexedLine ll = new LengthIndexedLine(geometry.getGeometryN(i));
+                points.add(ll.extractPoint(start*length));
+            }
+            return geometry.getFactory().createMultiPointFromCoords(points.toArray(new Coordinate[0]));
+        }
+        throw new SQLException("Only LineString or MultiLineString are supported");
+    }
+}

h2gis-functions/src/main/java/org/h2gis/functions/spatial/linear_referencing/ST_LineSubstring.java

@@ -0,0 +1,92 @@
+/**
+ * H2GIS is a library that brings spatial support to the H2 Database Engine
+ * <a href="http://www.h2database.com">http://www.h2database.com</a>. H2GIS is developed by CNRS
+ * <a href="http://www.cnrs.fr/">http://www.cnrs.fr/</a>.
+ *
+ * This code is part of the H2GIS project. H2GIS is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU
+ * Lesser General Public License as published by the Free Software Foundation;
+ * version 3.0 of the License.
+ *
+ * H2GIS is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
+ * for more details <http://www.gnu.org/licenses/>.
+ *
+ *
+ * For more information, please consult: <a href="http://www.h2gis.org/">http://www.h2gis.org/</a>
+ * or contact directly: info_at_h2gis.org
+ */
+
+package org.h2gis.functions.spatial.linear_referencing;
+
+import org.h2gis.api.DeterministicScalarFunction;
+import org.locationtech.jts.geom.Geometry;
+import org.locationtech.jts.geom.LineString;
+import org.locationtech.jts.geom.MultiLineString;
+import org.locationtech.jts.linearref.LengthIndexedLine;
+
+import java.sql.SQLException;
+import java.util.ArrayList;
+
+/**
+ * @author  Erwan Bocher, CNRS (2023)
+ * Extract a section of the input line starting and ending at the given fractions.
+ */
+public class ST_LineSubstring extends DeterministicScalarFunction {
+
+
+    public ST_LineSubstring(){
+        addProperty(PROP_REMARKS, "Extract a section of the input LineString or MultiLineString starting and ending at the given fractions.");
+    }
+
+    @Override
+    public String getJavaStaticMethod() {
+        return "execute";
+    }
+
+    /**
+     * Extract a section of the input LineString or MultiLineString starting and ending at the given fractions.
+     * @param geometry the input lines
+     * @param start the start fraction between 0 and 1
+     * @param end the end fraction between 0 and 1
+     * @return single or multiparts lines
+     * @throws SQLException
+     */
+    public static Geometry execute(Geometry geometry, double start, double end) throws SQLException {
+        if(geometry==null){
+            return null;
+        }
+        if ( start < 0 || start > 1 ){
+            throw new SQLException("Allowed between 0 and  1");
+        }
+
+        if ( end < 0 || end > 1 ){
+            throw new SQLException("Allowed between 0 and  1");
+        }
+
+        if(start> end){
+            throw new SQLException("Start fraction must be smaller than end fraction");
+        }
+        if(geometry.isEmpty()){
+            return geometry;
+        }
+
+        if(geometry instanceof LineString){
+            double length = geometry.getLength();
+            LengthIndexedLine ll = new LengthIndexedLine(geometry);
+            return ll.extractLine(start*length, end*length);
+        } else if (geometry instanceof MultiLineString) {
+            int nb = geometry.getNumGeometries();
+            ArrayList<LineString> lines = new ArrayList<>();
+            for (int i = 0; i < nb; i++) {
+                Geometry line = geometry.getGeometryN(i);
+                double length = line.getLength();
+                LengthIndexedLine ll = new LengthIndexedLine(geometry.getGeometryN(i));
+                lines.add((LineString) ll.extractLine(start*length, end*length));
+            }
+            return geometry.getFactory().createMultiLineString(lines.toArray(new LineString[0]));
+        }
+        throw new SQLException("Only LineString or MultiLineString are supported");
+    }
+}

h2gis-functions/src/test/java/org/h2gis/functions/spatial/linear_referencing/LinearReferencingTest.java

@@ -0,0 +1,117 @@
+/**
+ * H2GIS is a library that brings spatial support to the H2 Database Engine
+ * <a href="http://www.h2database.com">http://www.h2database.com</a>. H2GIS is developed by CNRS
+ * <a href="http://www.cnrs.fr/">http://www.cnrs.fr/</a>.
+ *
+ * This code is part of the H2GIS project. H2GIS is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU
+ * Lesser General Public License as published by the Free Software Foundation;
+ * version 3.0 of the License.
+ *
+ * H2GIS is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
+ * for more details <http://www.gnu.org/licenses/>.
+ *
+ *
+ * For more information, please consult: <a href="http://www.h2gis.org/">http://www.h2gis.org/</a>
+ * or contact directly: info_at_h2gis.org
+ */
+package org.h2gis.functions.spatial.linear_referencing;
+
+import org.h2gis.functions.factory.H2GISDBFactory;
+import org.junit.jupiter.api.*;
+
+import java.sql.Connection;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+
+import static org.h2gis.unitTest.GeometryAsserts.assertGeometryEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+/**
+ *  @author  Erwan Bocher, CNRS (2023)
+ */
+public class LinearReferencingTest {
+
+    private static Connection connection;
+    private Statement st;
+
+    @BeforeAll
+    public static void tearUp() throws Exception {
+        connection = H2GISDBFactory.createSpatialDataBase(LinearReferencingTest.class.getSimpleName());
+    }
+
+    @AfterAll
+    public static void tearDown() throws Exception {
+        connection.close();
+    }
+
+    @BeforeEach
+    public void setUpStatement() throws Exception {
+        st = connection.createStatement();
+    }
+
+    @AfterEach
+    public void tearDownStatement() throws Exception {
+        st.close();
+    }
+
+    @Test
+    public void test_ST_LineSubstring1() throws Exception {
+        ResultSet rs = st.executeQuery("SELECT ST_LineSubstring('LINESTRING(0 0, 10 0)'::GEOMETRY, 0, 0.5)");
+        assertTrue(rs.next());
+        assertGeometryEquals("LINESTRING(0 0, 5 0)", rs.getObject(1));
+        rs.close();
+    }
+
+    @Test
+    public void test_ST_LineSubstring2() throws Exception {
+        assertThrows(SQLException.class, () -> {
+            st.executeQuery("SELECT ST_LineSubstring('LINESTRING(0 0, 10 0)'::GEOMETRY, 1, 10)");
+        });
+    }
+
+    @Test
+    public void test_ST_LineSubstring3() throws Exception {
+        ResultSet rs = st.executeQuery("SELECT ST_LineSubstring('MULTILINESTRING((0 0, 10 0), (10 10, 10 20))'::GEOMETRY, 0, 0.5)");
+        assertTrue(rs.next());
+        assertGeometryEquals("MULTILINESTRING ((0 0, 5 0), (10 10, 10 15))", rs.getObject(1));
+        rs.close();
+    }
+
+    @Test
+    public void test_ST_LineSubstring4() throws Exception {
+        ResultSet rs = st.executeQuery("SELECT ST_LineSubstring('LINESTRINGZ(0 0 0, 10 0 10)'::GEOMETRY, 0, 0.5)");
+        assertTrue(rs.next());
+        assertGeometryEquals("LINESTRING Z (0 0 0, 5 0 5)", rs.getObject(1));
+        rs.close();
+    }
+
+    @Test
+    public void test_ST_LineInterpolatePoint1() throws Exception {
+        ResultSet rs = st.executeQuery("SELECT ST_LineInterpolatePoint('LINESTRING(0 0, 10 0)'::GEOMETRY, 0.5)");
+        assertTrue(rs.next());
+        assertGeometryEquals("POINT(5 0)", rs.getObject(1));
+        rs.close();
+    }
+
+    @Test
+    public void test_ST_LineInterpolatePoint2() throws Exception {
+        ResultSet rs = st.executeQuery("SELECT ST_LineInterpolatePoint('MULTILINESTRING((0 0, 10 0), (10 10, 10 20))'::GEOMETRY,0.5)");
+        assertTrue(rs.next());
+        assertGeometryEquals("MULTIPOINT ((5 0), (10 15))", rs.getObject(1));
+        rs.close();
+    }
+
+    @Test
+    public void test_ST_LineInterpolatePoint3() throws Exception {
+        ResultSet rs = st.executeQuery("SELECT ST_LineInterpolatePoint('LINESTRINGZ(0 0 0, 10 0 10)'::GEOMETRY, 0.5)");
+        assertTrue(rs.next());
+        assertGeometryEquals("POINT Z (5 0 5)", rs.getObject(1));
+        rs.close();
+    }
+
+}