[geos-commits] r3099 - trunk/include/geos/geom

[svn_geos at osgeo.org]

Author: strk
Date: 2010-08-27 14:13:44 +0000 (Fri, 27 Aug 2010)
New Revision: 3099

Modified:
   trunk/include/geos/geom/BinaryOp.h
Log:
Add code to check validity of CommonBits removal policy op (known as EnhancedPreicionOp in JTS). The check can be turned on at compile time. Currently defaults to off to avoid breaking a previously-almost-working test (robustness-invalid-output.xml). It'll need some discussion before going on with this as to whether we can accept to return invalid geometries or not..


Modified: trunk/include/geos/geom/BinaryOp.h
===================================================================
--- trunk/include/geos/geom/BinaryOp.h	2010-08-27 13:53:23 UTC (rev 3098)
+++ trunk/include/geos/geom/BinaryOp.h	2010-08-27 14:13:44 UTC (rev 3099)
@@ -58,6 +58,7 @@
 
 #include <geos/simplify/TopologyPreservingSimplifier.h>
 #include <geos/operation/valid/IsValidOp.h>
+#include <geos/operation/valid/TopologyValidationError.h>
 #include <geos/util/TopologyException.h>
 #include <geos/util.h>
 
@@ -65,7 +66,12 @@
 
 //#define GEOS_DEBUG_BINARYOP 1
 
+#ifdef GEOS_DEBUG_BINARYOP
+# include <iostream>
+# include <iomanip>
+#endif
 
+
 /*
  * Always try original input first
  */
@@ -101,6 +107,19 @@
 #endif
 
 /*
+ * Check validity of operation performed
+ * by common bits removal policy.
+ *
+ * This matches what EnhancedPrecisionOp does in JTS
+ * and fixes 5 tests of invalid outputs in our testsuite
+ * (stmlf-cases-20061020-invalid-output.xml)
+ * and breaks 1 test (robustness-invalid-output.xml) so much
+ * to prevent a result.
+ *
+ */
+//#define GEOS_CHECK_COMMONBITS_VALIDITY 1
+
+/*
  * Use snapping policy
  */
 #ifndef USE_SNAPPING_POLICY
@@ -116,8 +135,15 @@
 	operation::valid::IsValidOp ivo(&g);
 	if ( ! ivo.isValid() )
 	{
+#ifdef GEOS_DEBUG_BINARYOP
+		using operation::valid::TopologyValidationError;
+		TopologyValidationError* err = ivo.getValidationError();
 		std::cerr << label << " is INVALID: "
-			<< ivo.getValidationError()->toString() << std::endl;
+			<< err->toString()
+			<< " (" << std::setprecision(20)
+			<< err->getCoordinate() << ")"
+			<< std::endl;
+#endif
 		return false;
 	} 
 	return true;
@@ -143,7 +169,7 @@
 	// (not commonbits-removed) geoms
 	double snapTolerance = GeometrySnapper::computeOverlaySnapTolerance(*g0, *g1);
 #if GEOS_DEBUG_BINARYOP
-	std::cerr<<"Computed snap tolerance: "<<snapTolerance<<std::endl;
+	std::cerr<< std::setprecision(20) << "Computed snap tolerance: "<<snapTolerance<<std::endl;
 #endif
 
 
@@ -151,6 +177,9 @@
 	// Compute common bits
 	geos::precision::CommonBitsRemover cbr;
 	cbr.add(g0); cbr.add(g1);
+#if GEOS_DEBUG_BINARYOP
+	std::cerr<<"Computed common bits: "<<cbr.getCommonCoordinate()<<std::endl;
+#endif
 
 	// Now remove common bits
 	GeomPtr rG0( cbr.removeCommonBits(g0->clone()) );
@@ -168,6 +197,7 @@
 	const Geometry& operand1 = *g1
 #endif
 
+
 	GeometrySnapper snapper0( operand0 );
 	GeomPtr snapG0( snapper0.snapTo(operand1, snapTolerance) );
 
@@ -230,6 +260,12 @@
 
 #ifdef USE_COMMONBITS_POLICY
 	// Try removing common bits (possibly obsoleted by snapping below)
+	//
+	// NOTE: this policy was _later_ implemented 
+	//       in JTS as EnhancedPrecisionOp
+	// TODO: consider using the now-ported EnhancedPrecisionOp
+	//       here too
+	// 
 	try
 	{
 		GeomPtr rG0;
@@ -257,12 +293,30 @@
 		check_valid(*ret, "CBR: result (before common-bits addition)");
 #endif
 
-		cbr.addCommonBits( ret.get() );
+		cbr.addCommonBits( ret.get() ); 
 
 #if GEOS_DEBUG_BINARYOP
-		check_valid(*ret, "CBR: result (after common-bits addition)");
+		check_valid(*ret, "CBR: result (before common-bits addition)");
 #endif
 
+#if GEOS_CHECK_COMMONBITS_VALIDITY
+		// check that result is a valid geometry after the
+		// reshift to orginal precision (see EnhancedPrecisionOp)
+		using operation::valid::IsValidOp;
+		using operation::valid::TopologyValidationError;
+		using util::TopologyException;
+		IsValidOp ivo(ret.get());
+		if ( ! ivo.isValid() )
+		{
+			TopologyValidationError* e = ivo.getValidationError();
+			throw TopologyException(
+				"Result of overlay became invalid "
+				"after re-addin common bits of operand "
+				"coordinates: " + e->toString(),
+			        e->getCoordinate());
+		}
+#endif // GEOS_CHECK_COMMONBITS_VALIDITY
+
 		return ret;
 	}
 	catch (const util::TopologyException& ex)