Fix Douglas Peucker simplifier for XYZM coordinates (#1045)

locationtech · Jan 3, 2025 · 658365a · 658365a
1 parent b1313ad
commit 658365a
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Showing 3 changed files with 35 additions and 12 deletions.
diff --git a/modules/core/src/main/java/org/locationtech/jts/simplify/DouglasPeuckerLineSimplifier.java b/modules/core/src/main/java/org/locationtech/jts/simplify/DouglasPeuckerLineSimplifier.java
@@ -68,7 +68,7 @@ public Coordinate[] simplify()
     CoordinateList coordList = new CoordinateList();
     for (int i = 0; i < pts.length; i++) {
       if (usePt[i])
-        coordList.add(new Coordinate(pts[i]));
+        coordList.add(pts[i].copy());
     }
 
     if (! isPreserveEndpoint && CoordinateArrays.isRing(pts)) {

diff --git a/modules/core/src/test/java/org/locationtech/jts/simplify/DouglasPeuckerSimplifierTest.java b/modules/core/src/test/java/org/locationtech/jts/simplify/DouglasPeuckerSimplifierTest.java
@@ -86,6 +86,12 @@ public void testLineStringTiny() {
         10,
         "LINESTRING (0 5, 5 5)");
   }
+
+  public void testLineStringWithFourDimensions() {
+    checkDPXYZM("LINESTRING ZM(0 5 114.6 1709024189000, 1 5 114.6 1709024190000, 2 5 114.5 1709024192000, 5 5 114.5 1709024196000)",
+        10,
+        "LINESTRING ZM(0 5 114.6 1709024189000, 5 5 114.5 1709024196000)");
+  }
 
   public void testMultiPoint() {
     checkDPNoChange("MULTIPOINT(80 200, 240 200, 240 60, 80 60, 80 200, 140 199, 120 120)",
@@ -166,7 +172,13 @@ private void checkDP(String wkt, double tolerance, String wktExpected) {
     Geometry expected = read(wktExpected);
     checkEqual(expected, result);
   }
-
+    private void checkDPXYZM(String wkt, double tolerance, String wktExpected) {
+    Geometry geom = read(wkt);
+    Geometry result = DouglasPeuckerSimplifier.simplify(geom, tolerance);
+    Geometry expected = read(wktExpected);
+    checkEqualXYZM(expected, result);
+  }
+
   private void checkDPNoChange(String wkt, double tolerance) {
     checkDP(wkt, tolerance, wkt);
   }

diff --git a/modules/core/src/test/java/test/jts/GeometryTestCase.java b/modules/core/src/test/java/test/jts/GeometryTestCase.java
@@ -126,48 +126,60 @@ protected void checkEqual(Geometry expected, Geometry actual, double tolerance)
   protected void checkEqualXYZ(Geometry expected, Geometry actual) {
     Geometry actualNorm = actual.norm();
     Geometry expectedNorm = expected.norm();
-    boolean equal = equalsExactXYZ(actualNorm, expectedNorm);
+    boolean equal = equalsExactMultipleDimension(actualNorm, expectedNorm, 3);
     if (! equal) {
       System.out.format(CHECK_EQUAL_FAIL, 
           writerZ.write(expectedNorm), 
           writerZ.write(actualNorm) );
     }
     assertTrue(equal);
   }
+
+  protected void checkEqualXYZM(Geometry expected, Geometry actual) {
+    Geometry actualNorm = actual.norm();
+    Geometry expectedNorm = expected.norm();
+    boolean equal = equalsExactMultipleDimension(actualNorm, expectedNorm, 4);
+    if (! equal) {
+      System.out.format(CHECK_EQUAL_FAIL,
+          writerZ.write(expectedNorm),
+          writerZ.write(actualNorm) );
+    }
+    assertTrue(equal);
+  }
 
-  private boolean equalsExactXYZ(Geometry a, Geometry b) {
+  private boolean equalsExactMultipleDimension(Geometry a, Geometry b, int dimension) {
     if (a.getClass() != b.getClass()) return false;
     if (a.getNumGeometries() != b.getNumGeometries()) return false;
     if (a instanceof Point) {
-      return isEqualDim(((Point) a).getCoordinateSequence(), ((Point) b).getCoordinateSequence(), 3);
+      return isEqualDim(((Point) a).getCoordinateSequence(), ((Point) b).getCoordinateSequence(), dimension);
     }
     else if (a instanceof LineString) {
-      return isEqualDim(((LineString) a).getCoordinateSequence(), ((LineString) b).getCoordinateSequence(), 3);
+      return isEqualDim(((LineString) a).getCoordinateSequence(), ((LineString) b).getCoordinateSequence(), dimension);
     }
     else if (a instanceof Polygon) {
-      return equalsExactXYZPolygon( (Polygon) a, (Polygon) b);
+      return equalsExactMultipleDimensionPolygon( (Polygon) a, (Polygon) b, dimension);
     }
     else if (a instanceof GeometryCollection) {
       for (int i = 0; i < a.getNumGeometries(); i++) {
-        if (! equalsExactXYZ(a.getGeometryN(i), b.getGeometryN(i)))
+        if (! equalsExactMultipleDimension(a.getGeometryN(i), b.getGeometryN(i), dimension))
           return false;
       }
       return true;
     }
     return false;
   }
 
-  private boolean equalsExactXYZPolygon(Polygon a, Polygon b) {
+  private boolean equalsExactMultipleDimensionPolygon(Polygon a, Polygon b, int dimension) {
     LinearRing aShell = a.getExteriorRing();
     LinearRing bShell = b.getExteriorRing();
-    if (! isEqualDim(aShell.getCoordinateSequence(), bShell.getCoordinateSequence(), 3))
+    if (! isEqualDim(aShell.getCoordinateSequence(), bShell.getCoordinateSequence(), dimension))
       return false;
     if (a.getNumInteriorRing() != b.getNumInteriorRing())
       return false;
     for (int i = 0; i < a.getNumInteriorRing(); i++) {
       LinearRing aHole = a.getInteriorRingN(i);
       LinearRing bHole = b.getInteriorRingN(i);
-      if (! isEqualDim(aHole.getCoordinateSequence(), bHole.getCoordinateSequence(), 3))
+      if (! isEqualDim(aHole.getCoordinateSequence(), bHole.getCoordinateSequence(), dimension))
         return false;        
     }
     return true;
@@ -198,7 +210,6 @@ protected void checkEqualXYZ(Coordinate expected, Coordinate actual) {
     assertEquals("Coordinate Y", expected.getY(), actual.getY() );
     assertEquals("Coordinate Z", expected.getZ(), actual.getZ() );
   }
-
   protected void checkEqualXY(String message, Coordinate expected, Coordinate actual) {
     assertEquals(message + " X", expected.getX(), actual.getX() );
     assertEquals(message + " Y", expected.getY(), actual.getY() );