Ensure that proj strings in different parameter order are matched

to user CRS on proj 6 builds
qgis · Dec 20, 2019 · 3f0af6e · 3f0af6e
1 parent a2c6bb9
commit 3f0af6e
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Showing 3 changed files with 106 additions and 5 deletions.
diff --git a/src/core/qgscoordinatereferencesystem.cpp b/src/core/qgscoordinatereferencesystem.cpp
@@ -831,14 +831,25 @@ bool QgsCoordinateReferenceSystem::createFromProj( const QString &projString )
       }
     }
   }
-#endif
 
-#if PROJ_VERSION_MAJOR>=6
-  // try to match against known user crses
+  // try a direct match against user crses
   QgsCoordinateReferenceSystem::RecordMap myRecord = getRecord( "select * from tbl_srs where parameters=" + QgsSqliteUtils::quotedString( myProj4String ) + " order by deprecated" );
+  long id = 0;
   if ( !myRecord.empty() )
   {
-    long id = myRecord[QStringLiteral( "srs_id" )].toLong();
+    id = myRecord[QStringLiteral( "srs_id" )].toLong();
+    if ( id >= USER_CRS_START_ID )
+    {
+      createFromSrsId( id );
+    }
+  }
+  if ( id < USER_CRS_START_ID )
+  {
+    // no direct matches, so go ahead and create a new proj object based on the proj string alone.
+    setProj4String( myProj4String );
+
+    // lastly, try a tolerant match of the created proj object against all user CRSes (allowing differences in parameter order during the comparison)
+    id = matchToUserCrs();
     if ( id >= USER_CRS_START_ID )
     {
       createFromSrsId( id );
@@ -1006,7 +1017,6 @@ bool QgsCoordinateReferenceSystem::createFromProj( const QString &projString )
       d->mIsValid = false;
     }
   }
-#endif
 
   // if we failed to look up the projection in database, don't worry. we can still use it :)
   if ( !d->mIsValid )
@@ -1015,6 +1025,7 @@ bool QgsCoordinateReferenceSystem::createFromProj( const QString &projString )
     //setProj4String will set mIsValidFlag to true if there is no issue
     setProjString( myProj4String );
   }
+#endif
 
   locker.changeMode( QgsReadWriteLocker::Write );
   if ( !sDisableProjCache )
@@ -2348,6 +2359,74 @@ bool QgsCoordinateReferenceSystem::loadFromAuthCode( const QString &auth, const
 
   return true;
 }
+
+QList<long> QgsCoordinateReferenceSystem::userSrsIds()
+{
+  QList<long> results;
+  // check user defined projection database
+  const QString db = QgsApplication::qgisUserDatabaseFilePath();
+
+  QFileInfo myInfo( db );
+  if ( !myInfo.exists() )
+  {
+    QgsDebugMsg( "failed : " + db + " does not exist!" );
+    return results;
+  }
+
+  sqlite3_database_unique_ptr database;
+  sqlite3_statement_unique_ptr statement;
+
+  //check the db is available
+  int result = openDatabase( db, database );
+  if ( result != SQLITE_OK )
+  {
+    QgsDebugMsg( "failed : " + db + " could not be opened!" );
+    return results;
+  }
+
+  QString sql = QStringLiteral( "select srs_id from tbl_srs where srs_id >= %1" ).arg( USER_CRS_START_ID );
+  int rc;
+  statement = database.prepare( sql, rc );
+  while ( true )
+  {
+    int ret = statement.step();
+
+    if ( ret == SQLITE_DONE )
+    {
+      // there are no more rows to fetch - we can stop looping
+      break;
+    }
+
+    if ( ret == SQLITE_ROW )
+    {
+      results.append( statement.columnAsInt64( 0 ) );
+    }
+    else
+    {
+      QgsMessageLog::logMessage( QObject::tr( "SQLite error: %2\nSQL: %1" ).arg( sql, sqlite3_errmsg( database.get() ) ), QObject::tr( "SpatiaLite" ) );
+      break;
+    }
+  }
+
+  return results;
+}
+
+long QgsCoordinateReferenceSystem::matchToUserCrs() const
+{
+  if ( !d->mPj )
+    return 0;
+
+  const QList< long > ids = userSrsIds();
+  for ( long id : ids )
+  {
+    QgsCoordinateReferenceSystem candidate = QgsCoordinateReferenceSystem::fromSrsId( id );
+    if ( candidate.projObject() && proj_is_equivalent_to( d->mPj.get(), candidate.projObject(), PJ_COMP_EQUIVALENT ) )
+    {
+      return id;
+    }
+  }
+  return 0;
+}
 #endif
 
 #if PROJ_VERSION_MAJOR<6

diff --git a/src/core/qgscoordinatereferencesystem.h b/src/core/qgscoordinatereferencesystem.h
@@ -931,6 +931,20 @@ class CORE_EXPORT QgsCoordinateReferenceSystem
 
 #if PROJ_VERSION_MAJOR>=6
     bool loadFromAuthCode( const QString &auth, const QString &code );
+
+    /**
+     * Returns a list of all users SRS IDs present in the CRS database.
+     */
+    static QList< long > userSrsIds();
+
+    /**
+     * Tries to match the current definition of the CRS to user CRSes.
+     *
+     * Uses proj's equivalent testing API so that matches are tolerant to differences in
+     * parameter order and naming for proj or WKT strings (internally, uses the PJ_COMP_EQUIVALENT
+     * criteria).
+     */
+    long matchToUserCrs() const;
 #endif
 
     /**

diff --git a/tests/src/core/testqgscoordinatereferencesystem.cpp b/tests/src/core/testqgscoordinatereferencesystem.cpp
@@ -1410,6 +1410,14 @@ void TestQgsCoordinateReferenceSystem::customProjString()
   QCOMPARE( crs.toWkt(), QStringLiteral( R"""(COMPD_CS["unknown",PROJCS["unknown",GEOGCS["unknown",DATUM["Unknown_based_on_Bessel_1841_ellipsoid",SPHEROID["Bessel 1841",6377397.155,299.1528128],TOWGS84[595.75,121.09,515.5,8.227,-1.5193,5.5971,-2.6729]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]]],PROJECTION["Oblique_Stereographic"],PARAMETER["latitude_of_origin",47.4860018439082],PARAMETER["central_meridian",19.0491441390302],PARAMETER["scale_factor",1],PARAMETER["false_easting",500000],PARAMETER["false_northing",500000],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AXIS["Easting",EAST],AXIS["Northing",NORTH]],VERT_CS["unknown",VERT_DATUM["unknown",2005],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AXIS["Gravity-related height",UP]]])""" ) );
   QCOMPARE( crs.authid(), QStringLiteral( "USER:%1" ).arg( id ) );
 
+  // make sure it matches to user crs when parameter order is different
+  QgsCoordinateReferenceSystem::invalidateCache();
+  crs = QgsCoordinateReferenceSystem::fromProj4( QStringLiteral( "+proj=sterea +lon_0=19.0491441390302 +lat_0=47.4860018439082 +k=1 +y_0=500000 +ellps=bessel +x_0=500000 +towgs84=595.75,121.09,515.50,8.2270,-1.5193,5.5971,-2.6729 +units=m +vunits=m +no_defs" ) );
+  QVERIFY( crs.isValid() );
+  QCOMPARE( crs.authid(), QStringLiteral( "USER:%1" ).arg( id ) );
+  QCOMPARE( crs.toProj4(), QStringLiteral( "+proj=sterea +lat_0=47.4860018439082 +lon_0=19.0491441390302 +k=1 +x_0=500000 +y_0=500000 +ellps=bessel +towgs84=595.75,121.09,515.50,8.2270,-1.5193,5.5971,-2.6729 +units=m +vunits=m +no_defs" ) );
+  QCOMPARE( crs.toWkt(), QStringLiteral( R"""(COMPD_CS["unknown",PROJCS["unknown",GEOGCS["unknown",DATUM["Unknown_based_on_Bessel_1841_ellipsoid",SPHEROID["Bessel 1841",6377397.155,299.1528128],TOWGS84[595.75,121.09,515.5,8.227,-1.5193,5.5971,-2.6729]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]]],PROJECTION["Oblique_Stereographic"],PARAMETER["latitude_of_origin",47.4860018439082],PARAMETER["central_meridian",19.0491441390302],PARAMETER["scale_factor",1],PARAMETER["false_easting",500000],PARAMETER["false_northing",500000],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AXIS["Easting",EAST],AXIS["Northing",NORTH]],VERT_CS["unknown",VERT_DATUM["unknown",2005],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AXIS["Gravity-related height",UP]]])""" ) );
+
 #endif
 }