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# BinaryOp.h

    00001 /**********************************************************************
    00002  * $Id: BinaryOp.h 3606 2012-04-10 15:02:23Z strk $
    00003  *
    00004  * GEOS - Geometry Engine Open Source
    00005  * http://geos.refractions.net
    00006  *
    00007  * Copyright (C) 2006 Refractions Research Inc.
    00008  *
    00009  * This is free software; you can redistribute and/or modify it under
    00010  * the terms of the GNU Lesser General Public Licence as published
    00011  * by the Free Software Foundation.
    00012  * See the COPYING file for more information.
    00013  *
    00014  **********************************************************************
    00015  *
    00016  * Last port: ORIGINAL WORK
    00017  *
    00018  **********************************************************************
    00019  *
    00020  * This file provides a single templated function, taking two
    00021  * const Geometry pointers, applying a binary operator to them
    00022  * and returning a result Geometry in an auto_ptr<>.
    00023  *
    00024  * The binary operator is expected to take two const Geometry pointers
    00025  * and return a newly allocated Geometry pointer, possibly throwing
    00026  * a TopologyException to signal it couldn't succeed due to robustness
    00027  * issues.
    00028  *
    00029  * This function will catch TopologyExceptions and try again with
    00030  * slightly modified versions of the input. The following heuristic
    00031  * is used:
    00032  *
    00033  *      - Try with original input.
    00034  *      - Try removing common bits from input coordinate values
    00035  *      - Try snaping input geometries to each other
    00036  *      - Try snaping input coordinates to a increasing grid (size from 1/25 to 1)
    00037  *      - Try simplifiying input with increasing tolerance (from 0.01 to 0.04)
    00038  *
    00039  * If none of the step succeeds the original exception is thrown.
    00040  *
    00041  * Note that you can skip Grid snapping, Geometry snapping and Simplify policies
    00042  * by a compile-time define when building geos.
    00043  * See USE_TP_SIMPLIFY_POLICY, USE_PRECISION_REDUCTION_POLICY and
    00044  * USE_SNAPPING_POLICY macros below.
    00045  *
    00046  *
    00047  **********************************************************************/
    00048
    00049 #ifndef GEOS_GEOM_BINARYOP_H
    00050 #define GEOS_GEOM_BINARYOP_H
    00051
    00052 #include <geos/geom/Geometry.h>
    00053 #include <geos/geom/PrecisionModel.h>
    00054 #include <geos/precision/CommonBitsRemover.h>
    00055 #include <geos/precision/SimpleGeometryPrecisionReducer.h>
    00056
    00057 #include <geos/operation/overlay/snap/GeometrySnapper.h>
    00058
    00059 #include <geos/simplify/TopologyPreservingSimplifier.h>
    00060 #include <geos/operation/valid/IsValidOp.h>
    00061 #include <geos/operation/valid/TopologyValidationError.h>
    00062 #include <geos/util/TopologyException.h>
    00063 #include <geos/util.h>
    00064
    00065 #include <memory> // for auto_ptr
    00066
    00067 //#define GEOS_DEBUG_BINARYOP 1
    00068
    00069 #ifdef GEOS_DEBUG_BINARYOP
    00070 # include <iostream>
    00071 # include <iomanip>
    00072 # include <sstream>
    00073 #endif
    00074
    00075
    00076 /*
    00077  * Always try original input first
    00078  */
    00079 #ifndef USE_ORIGINAL_INPUT
    00080 # define USE_ORIGINAL_INPUT 1
    00081 #endif
    00082
    00083 /*
    00084  * Define this to use PrecisionReduction policy
    00085  * in an attempt at by-passing binary operation
    00086  * robustness problems (handles TopologyExceptions)
    00087  */
    00088 #ifndef USE_PRECISION_REDUCTION_POLICY
    00089 //# define USE_PRECISION_REDUCTION_POLICY 1
    00090 #endif
    00091
    00092 /*
    00093  * Define this to use TopologyPreserving simplification policy
    00094  * in an attempt at by-passing binary operation
    00095  * robustness problems (handles TopologyExceptions)
    00096  */
    00097 #ifndef USE_TP_SIMPLIFY_POLICY
    00098 //# define USE_TP_SIMPLIFY_POLICY 1
    00099 #endif
    00100
    00101 /*
    00102  * Use common bits removal policy.
    00103  * If enabled, this would be tried /before/
    00104  * Geometry snapping.
    00105  */
    00106 #ifndef USE_COMMONBITS_POLICY
    00107 # define USE_COMMONBITS_POLICY 1
    00108 #endif
    00109
    00110 /*
    00111  * Check validity of operation performed
    00112  * by common bits removal policy.
    00113  *
    00114  * This matches what EnhancedPrecisionOp does in JTS
    00115  * and fixes 5 tests of invalid outputs in our testsuite
    00116  * (stmlf-cases-20061020-invalid-output.xml)
    00117  * and breaks 1 test (robustness-invalid-output.xml) so much
    00118  * to prevent a result.
    00119  *
    00120  */
    00121 #define GEOS_CHECK_COMMONBITS_VALIDITY 1
    00122
    00123 /*
    00124  * Use snapping policy
    00125  */
    00126 #ifndef USE_SNAPPING_POLICY
    00127 # define USE_SNAPPING_POLICY 1
    00128 #endif
    00129
    00130 namespace geos {
    00131 namespace geom { // geos::geom
    00132
    00133 inline bool
    00134 check_valid(const Geometry& g, const std::string& label)
    00135 {
    00136         operation::valid::IsValidOp ivo(&g);
    00137         if ( ! ivo.isValid() )
    00138         {
    00139 #ifdef GEOS_DEBUG_BINARYOP
    00140                 using operation::valid::TopologyValidationError;
    00141                 TopologyValidationError* err = ivo.getValidationError();
    00142                 std::cerr << label << " is INVALID: "
    00143                         << err->toString()
    00144                         << " (" << std::setprecision(20)
    00145                         << err->getCoordinate() << ")"
    00146                         << std::endl;
    00147 #else
    00148         (void)label;
    00149 #endif
    00150                 return false;
    00151         }
    00152         return true;
    00153 }
    00154
    00155 /* A single component may become a multi component */
    00156 inline std::auto_ptr<Geometry>
    00157 fix_self_intersections(std::auto_ptr<Geometry> g, const std::string& label)
    00158 {
    00159   // TODO: check for presence of self-intersections first ?
    00160   return g->Union();
    00161 }
    00162
    00163
    00169 template <class BinOp>
    00170 std::auto_ptr<Geometry>
    00171 SnapOp(const Geometry* g0, const Geometry *g1, BinOp _Op)
    00172 {
    00173         typedef std::auto_ptr<Geometry> GeomPtr;
    00174
    00175 #define CBR_BEFORE_SNAPPING 1
    00176
    00177         //using geos::precision::GeometrySnapper;
    00178         using geos::operation::overlay::snap::GeometrySnapper;
    00179
    00180         // Snap tolerance must be computed on the original
    00181         // (not commonbits-removed) geoms
    00182         double snapTolerance = GeometrySnapper::computeOverlaySnapTolerance(*g0, *g1);
    00183 #if GEOS_DEBUG_BINARYOP
    00184         std::cerr<< std::setprecision(20) << "Computed snap tolerance: "<<snapTolerance<<std::endl;
    00185 #endif
    00186
    00187
    00188 #if CBR_BEFORE_SNAPPING
    00189         // Compute common bits
    00190         geos::precision::CommonBitsRemover cbr;
    00191         cbr.add(g0); cbr.add(g1);
    00192 #if GEOS_DEBUG_BINARYOP
    00193         std::cerr<<"Computed common bits: "<<cbr.getCommonCoordinate()<<std::endl;
    00194 #endif
    00195
    00196         // Now remove common bits
    00197         GeomPtr rG0( cbr.removeCommonBits(g0->clone()) );
    00198         GeomPtr rG1( cbr.removeCommonBits(g1->clone()) );
    00199
    00200 #if GEOS_DEBUG_BINARYOP
    00201         check_valid(*rG0, "CBR: removed-bits geom 0");
    00202         check_valid(*rG1, "CBR: removed-bits geom 1");
    00203 #endif
    00204
    00205         const Geometry& operand0 = *rG0;
    00206         const Geometry& operand1 = *rG1;
    00207 #else // don't CBR before snapping
    00208         const Geometry& operand0 = *g0;
    00209         const Geometry& operand1 = *g1;
    00210 #endif
    00211
    00212
    00213         GeometrySnapper snapper0( operand0 );
    00214         GeomPtr snapG0( snapper0.snapTo(operand1, snapTolerance) );
    00215         snapG0 = fix_self_intersections(snapG0, "SNAP: snapped geom 0");
    00216
    00217         // NOTE: second geom is snapped on the snapped first one
    00218         GeometrySnapper snapper1( operand1 );
    00219         GeomPtr snapG1( snapper1.snapTo(*snapG0, snapTolerance) );
    00220         snapG1 = fix_self_intersections(snapG1, "SNAP: snapped geom 1");
    00221
    00222         // Run the binary op
    00223         GeomPtr result( _Op(snapG0.get(), snapG1.get()) );
    00224
    00225 #if GEOS_DEBUG_BINARYOP
    00226         check_valid(*result, "SNAP: result (before common-bits addition");
    00227 #endif
    00228
    00229 #if CBR_BEFORE_SNAPPING
    00230         // Add common bits back in
    00231         cbr.addCommonBits( result.get() );
    00232         result = fix_self_intersections(result, "SNAP: result (after common-bits addition)");
    00233 #endif
    00234
    00235 #if GEOS_DEBUG_BINARYOP
    00236         check_valid(*result, "SNAP: result (after common-bits addition");
    00237 #endif
    00238
    00239         return result;
    00240 }
    00241
    00242 template <class BinOp>
    00243 std::auto_ptr<Geometry>
    00244 BinaryOp(const Geometry* g0, const Geometry *g1, BinOp _Op)
    00245 {
    00246         typedef std::auto_ptr<Geometry> GeomPtr;
    00247
    00248         GeomPtr ret;
    00249         geos::util::TopologyException origException;
    00250
    00251 #ifdef USE_ORIGINAL_INPUT
    00252         // Try with original input
    00253         try
    00254         {
    00255 #if GEOS_DEBUG_BINARYOP
    00256                 std::cerr << "Trying with original input." << std::endl;
    00257 #endif
    00258                 ret.reset(_Op(g0, g1));
    00259                 return ret;
    00260         }
    00261         catch (const geos::util::TopologyException& ex)
    00262         {
    00263                 origException=ex;
    00264 #if GEOS_DEBUG_BINARYOP
    00265                 std::cerr << "Original exception: " << ex.what() << std::endl;
    00266 #endif
    00267         }
    00268
    00269 //#if GEOS_DEBUG_BINARYOP
    00270   // Should we just give up here ?
    00271   check_valid(*g0, "Input geom 0");
    00272   check_valid(*g1, "Input geom 1");
    00273 //#endif
    00274
    00275 #endif // USE_ORIGINAL_INPUT
    00276
    00277
    00278 #ifdef USE_COMMONBITS_POLICY
    00279         // Try removing common bits (possibly obsoleted by snapping below)
    00280         //
    00281         // NOTE: this policy was _later_ implemented
    00282         //       in JTS as EnhancedPrecisionOp
    00283         // TODO: consider using the now-ported EnhancedPrecisionOp
    00284         //       here too
    00285         //
    00286         try
    00287         {
    00288                 GeomPtr rG0;
    00289                 GeomPtr rG1;
    00290                 precision::CommonBitsRemover cbr;
    00291
    00292 #if GEOS_DEBUG_BINARYOP
    00293                 std::cerr << "Trying with Common Bits Remover (CBR)" << std::endl;
    00294 #endif
    00295
    00296                 cbr.add(g0);
    00297                 cbr.add(g1);
    00298
    00299                 rG0.reset( cbr.removeCommonBits(g0->clone()) );
    00300                 rG1.reset( cbr.removeCommonBits(g1->clone()) );
    00301
    00302 #if GEOS_DEBUG_BINARYOP
    00303                 check_valid(*rG0, "CBR: geom 0 (after common-bits removal)");
    00304                 check_valid(*rG1, "CBR: geom 1 (after common-bits removal)");
    00305 #endif
    00306
    00307                 ret.reset( _Op(rG0.get(), rG1.get()) );
    00308
    00309 #if GEOS_DEBUG_BINARYOP
    00310                 check_valid(*ret, "CBR: result (before common-bits addition)");
    00311 #endif
    00312
    00313                 cbr.addCommonBits( ret.get() );
    00314
    00315 #if GEOS_DEBUG_BINARYOP
    00316                 check_valid(*ret, "CBR: result (after common-bits addition)");
    00317 #endif
    00318
    00319                 // Common-bits removal policy could introduce self-intersections
    00320                 ret = fix_self_intersections(ret, "CBR: result (after common-bits addition)");
    00321
    00322 #if GEOS_DEBUG_BINARYOP
    00323                 check_valid(*ret, "CBR: result (after common-bits addition and fix_self_intersections)");
    00324 #endif
    00325
    00326 #if GEOS_CHECK_COMMONBITS_VALIDITY
    00327                 // check that result is a valid geometry after the
    00328                 // reshift to orginal precision (see EnhancedPrecisionOp)
    00329                 using operation::valid::IsValidOp;
    00330                 using operation::valid::TopologyValidationError;
    00331                 IsValidOp ivo(ret.get());
    00332                 if ( ! ivo.isValid() )
    00333                 {
    00334                         TopologyValidationError* e = ivo.getValidationError();
    00335                         throw geos::util::TopologyException(
    00336                                 "Result of overlay became invalid "
    00337                                 "after re-addin common bits of operand "
    00338                                 "coordinates: " + e->toString(),
    00339                                 e->getCoordinate());
    00340                 }
    00341 #endif // GEOS_CHECK_COMMONBITS_VALIDITY
    00342
    00343                 return ret;
    00344         }
    00345         catch (const geos::util::TopologyException& ex)
    00346         {
    00347         ::geos::ignore_unused_variable_warning(ex);
    00348 #if GEOS_DEBUG_BINARYOP
    00349                 std::cerr << "CBR: " << ex.what() << std::endl;
    00350 #endif
    00351         }
    00352 #endif
    00353
    00354         // Try with snapping
    00355         //
    00356         // TODO: possible optimization would be reusing the
    00357         //       already common-bit-removed inputs and just
    00358         //       apply geometry snapping, whereas the current
    00359         //       SnapOp function does both.
    00360 // {
    00361 #if USE_SNAPPING_POLICY
    00362
    00363 #if GEOS_DEBUG_BINARYOP
    00364         std::cerr << "Trying with snapping " << std::endl;
    00365 #endif
    00366
    00367         try {
    00368                 ret = SnapOp(g0, g1, _Op);
    00369 #if GEOS_DEBUG_BINARYOP
    00370         std::cerr << "SnapOp succeeded" << std::endl;
    00371 #endif
    00372                 return ret;
    00373
    00374         }
    00375         catch (const geos::util::TopologyException& ex)
    00376         {
    00377         ::geos::ignore_unused_variable_warning(ex);
    00378 #if GEOS_DEBUG_BINARYOP
    00379                 std::cerr << "SNAP: " << ex.what() << std::endl;
    00380 #endif
    00381         }
    00382
    00383 #endif // USE_SNAPPING_POLICY }
    00384
    00385
    00386
    00387 // {
    00388 #if USE_PRECISION_REDUCTION_POLICY
    00389
    00390
    00391         // Try reducing precision
    00392         try
    00393         {
    00394                 int maxPrecision=25;
    00395
    00396                 for (int precision=maxPrecision; precision; --precision)
    00397                 {
    00398                         std::auto_ptr<PrecisionModel> pm(new PrecisionModel(precision));
    00399 #if GEOS_DEBUG_BINARYOP
    00400                         std::cerr << "Trying with precision " << precision << std::endl;
    00401 #endif
    00402
    00403                         precision::SimpleGeometryPrecisionReducer reducer( pm.get() );
    00404                         GeomPtr rG0( reducer.reduce(g0) );
    00405                         GeomPtr rG1( reducer.reduce(g1) );
    00406
    00407                         try
    00408                         {
    00409                                 ret.reset( _Op(rG0.get(), rG1.get()) );
    00410                                 return ret;
    00411                         }
    00412                         catch (const geos::util::TopologyException& ex)
    00413                         {
    00414                                 if ( precision == 1 ) throw ex;
    00415 #if GEOS_DEBUG_BINARYOP
    00416                                 std::cerr << "Reduced with precision (" << precision << "): "
    00417                                           << ex.what() << std::endl;
    00418 #endif
    00419                         }
    00420
    00421                 }
    00422
    00423         }
    00424         catch (const geos::util::TopologyException& ex)
    00425         {
    00426 #if GEOS_DEBUG_BINARYOP
    00427                 std::cerr << "Reduced: " << ex.what() << std::endl;
    00428 #endif
    00429         }
    00430
    00431 #endif
    00432 // USE_PRECISION_REDUCTION_POLICY }
    00433
    00434 // {
    00435 #if USE_TP_SIMPLIFY_POLICY
    00436
    00437         // Try simplifying
    00438         try
    00439         {
    00440
    00441                 double maxTolerance = 0.04;
    00442                 double minTolerance = 0.01;
    00443                 double tolStep = 0.01;
    00444
    00445                 for (double tol = minTolerance; tol <= maxTolerance; tol += tolStep)
    00446                 {
    00447 #if GEOS_DEBUG_BINARYOP
    00448                         std::cerr << "Trying simplifying with tolerance " << tol << std::endl;
    00449 #endif
    00450
    00451                         GeomPtr rG0( simplify::TopologyPreservingSimplifier::simplify(g0, tol) );
    00452                         GeomPtr rG1( simplify::TopologyPreservingSimplifier::simplify(g1, tol) );
    00453
    00454                         try
    00455                         {
    00456                                 ret.reset( _Op(rG0.get(), rG1.get()) );
    00457                                 return ret;
    00458                         }
    00459                         catch (const geos::util::TopologyException& ex)
    00460                         {
    00461                                 if ( tol >= maxTolerance ) throw ex;
    00462 #if GEOS_DEBUG_BINARYOP
    00463                                 std::cerr << "Simplified with tolerance (" << tol << "): "
    00464                                           << ex.what() << std::endl;
    00465 #endif
    00466                         }
    00467
    00468                 }
    00469
    00470                 return ret;
    00471
    00472         }
    00473         catch (const geos::util::TopologyException& ex)
    00474         {
    00475 #if GEOS_DEBUG_BINARYOP
    00476                 std::cerr << "Simplified: " << ex.what() << std::endl;
    00477 #endif
    00478         }
    00479
    00480 #endif
    00481 // USE_TP_SIMPLIFY_POLICY }
    00482
    00483         throw origException;
    00484 }
    00485
    00486
    00487 } // namespace geos::geom
    00488 } // namespace geos
    00489
    00490 #endif // GEOS_GEOM_BINARYOP_H