Move all datum transform related methods to QgsDatumTransform

doc/api_break.dox

@@ -935,9 +935,9 @@ plugins calling these methods will need to be updated.
 - 'theNode', 'theDoc' parameters in readXML and writeXML have been renamed to 'node' and 'document' respectively
 - readXML() and writeXML() have been removed.
 - initialize() was removed.
-- datumTransformations() now returns a list of QgsCoordinateTransform.TransformPair instead of a list of lists.
+- datumTransformations() was moved to QgsDatumTransform, and now returns a list of QgsDatumTransform.TransformPair instead of a list of lists.
-- datumTransformString() was renamed to datumTransformToProj()
+- datumTransformString() was moved to QgsDatumTransform and renamed to datumTransformToProj()
-- datumTransformCrsInfo() was renamed to datumTransformInfo(), and now returns a QgsCoordinateTransform.TransformInfo object.
+- datumTransformCrsInfo() was moved to QgsDatumTransform and renamed to datumTransformInfo(), and now returns a QgsDatumTransform.TransformInfo object.
 - sourceDatumTransform() was renamed to sourceDatumTransformId()
 - setSourceDatumTransform() was renamed to setSourceDatumTransformId()
 - destinationDatumTransform() was renamed to destinationDatumTransformId()

python/core/qgscoordinatetransform.sip

@@ -28,6 +28,10 @@ transforms coordinates from the layer's coordinate system to the map canvas.
 .. note::
 
    Since QGIS 3.0 QgsCoordinateReferenceSystem objects are implicitly shared.
+
+.. seealso:: :py:class:`QgsDatumTransform`
+
+.. seealso:: :py:class:`QgsCoordinateTransformContext`
 %End
 
 %TypeHeaderCode
@@ -252,47 +256,6 @@ otherwise points are transformed from destination to source CRS.
     bool isShortCircuited() const;
 %Docstring
 Returns true if the transform short circuits because the source and destination are equivalent.
-%End
-
-    static QList< QgsDatumTransform::TransformPair > datumTransformations( const QgsCoordinateReferenceSystem &source, const QgsCoordinateReferenceSystem &destination );
-%Docstring
-Returns a list of datum transformations which are available for the given ``source`` and ``destination`` CRS.
-
-.. seealso:: :py:func:`datumTransformToProj()`
-
-.. seealso:: :py:func:`datumTransformInfo()`
-%End
-
-    static QString datumTransformToProj( int datumTransformId );
-%Docstring
-Returns a proj string representing the specified ``datumTransformId`` datum transform ID.
-
-.. seealso:: :py:func:`datumTransformations()`
-
-.. seealso:: :py:func:`datumTransformInfo()`
-
-.. seealso:: :py:func:`projStringToDatumTransformId()`
-%End
-
-    static int projStringToDatumTransformId( const QString &string );
-%Docstring
-Returns the datum transform ID corresponding to a specified proj ``string``.
-Returns -1 if matching datum ID was not found.
-
-.. seealso:: :py:func:`datumTransformToProj()`
-
-.. versionadded:: 3.0
-%End
-
-    static QgsDatumTransform::TransformInfo datumTransformInfo( int datumTransformId );
-%Docstring
-Returns detailed information about the specified ``datumTransformId``.
-If ``datumTransformId`` was not a valid transform ID, a TransformInfo with TransformInfo.datumTransformId of
--1 will be returned.
-
-.. seealso:: :py:func:`datumTransformations()`
-
-.. seealso:: :py:func:`datumTransformToProj()`
 %End
 
     int sourceDatumTransformId() const;

python/core/qgscoordinatetransformcontext.sip

@@ -37,6 +37,11 @@ applies for destination CRS transforms set using addDestinationDatumTransform().
    QgsCoordinateTransformContext objects are implicitly shared.
 
 
+.. seealso:: :py:class:`QgsDatumTransform`
+
+.. seealso:: :py:class:`QgsCoordinateTransform`
+
+
 .. versionadded:: 3.0
 %End
 

python/core/qgsdatumtransform.sip

@@ -8,11 +8,17 @@
 
 
 
+
+
 class QgsDatumTransform
 {
 %Docstring
 Contains methods and classes relating the datum transformations.
 
+.. seealso:: :py:class:`QgsCoordinateTransformContext`
+
+.. seealso:: :py:class:`QgsCoordinateTransform`
+
 .. versionadded:: 3.0
 %End
 
@@ -103,6 +109,46 @@ True if transform is deprecated
 %End
 
     };
+
+    static QList< QgsDatumTransform::TransformPair > datumTransformations( const QgsCoordinateReferenceSystem &source, const QgsCoordinateReferenceSystem &destination );
+%Docstring
+Returns a list of datum transformations which are available for the given ``source`` and ``destination`` CRS.
+
+.. seealso:: :py:func:`datumTransformToProj()`
+
+.. seealso:: :py:func:`datumTransformInfo()`
+%End
+
+    static QString datumTransformToProj( int datumTransformId );
+%Docstring
+Returns a proj string representing the specified ``datumTransformId`` datum transform ID.
+
+.. seealso:: :py:func:`datumTransformations()`
+
+.. seealso:: :py:func:`datumTransformInfo()`
+
+.. seealso:: :py:func:`projStringToDatumTransformId()`
+%End
+
+    static int projStringToDatumTransformId( const QString &string );
+%Docstring
+Returns the datum transform ID corresponding to a specified proj ``string``.
+Returns -1 if matching datum ID was not found.
+
+.. seealso:: :py:func:`datumTransformToProj()`
+%End
+
+    static QgsDatumTransform::TransformInfo datumTransformInfo( int datumTransformId );
+%Docstring
+Returns detailed information about the specified ``datumTransformId``.
+If ``datumTransformId`` was not a valid transform ID, a TransformInfo with TransformInfo.datumTransformId of
+-1 will be returned.
+
+.. seealso:: :py:func:`datumTransformations()`
+
+.. seealso:: :py:func:`datumTransformToProj()`
+%End
+
 };
 
 /************************************************************************

src/app/qgisapp.cpp

@@ -9151,7 +9151,7 @@ void QgisApp::projectCrsChanged()
     if ( !transformsToAskFor.contains( it.value()->crs() ) &&
          it.value()->crs() != QgsProject::instance()->crs() &&
          !QgsProject::instance()->transformContext().hasTransform( it.value()->crs(), QgsProject::instance()->crs() ) &&
-         QgsCoordinateTransform::datumTransformations( it.value()->crs(), QgsProject::instance()->crs() ).count() > 1 )
+         QgsDatumTransform::datumTransformations( it.value()->crs(), QgsProject::instance()->crs() ).count() > 1 )
     {
       transformsToAskFor.append( it.value()->crs() );
     }

src/app/qgsdatumtransformtablewidget.cpp

@@ -110,7 +110,7 @@ QVariant QgsDatumTransformTableModel::data( const QModelIndex &index, int role )
         case SourceTransformColumn:
           if ( sourceTransform != -1 )
           {
-            return QgsCoordinateTransform::datumTransformToProj( sourceTransform );
+            return QgsDatumTransform::datumTransformToProj( sourceTransform );
           }
           break;
         case DestinationCrsColumn:
@@ -119,7 +119,7 @@ QVariant QgsDatumTransformTableModel::data( const QModelIndex &index, int role )
         case DestinationTransformColumn:
           if ( destinationTransform != -1 )
           {
-            return QgsCoordinateTransform::datumTransformToProj( destinationTransform );
+            return QgsDatumTransform::datumTransformToProj( destinationTransform );
           }
           break;
         default:

src/core/CMakeLists.txt

@@ -161,6 +161,7 @@ SET(QGIS_CORE_SRCS
   qgsdatasourceuri.cpp
   qgsdataprovider.cpp
   qgsdatetimestatisticalsummary.cpp
+  qgsdatumtransform.cpp
   qgsdbfilterproxymodel.cpp
   qgsdefaultvalue.cpp
   qgsdiagramrenderer.cpp

src/core/qgscoordinatetransform.cpp

@@ -700,97 +700,6 @@ const char *finder( const char *name )
   return proj.toUtf8();
 }
 
-
-
-QList< QgsDatumTransform::TransformPair > QgsCoordinateTransform::datumTransformations( const QgsCoordinateReferenceSystem &srcCRS, const QgsCoordinateReferenceSystem &destCRS )
-{
-  QList< QgsDatumTransform::TransformPair > transformations;
-
-  QString srcGeoId = srcCRS.geographicCrsAuthId();
-  QString destGeoId = destCRS.geographicCrsAuthId();
-
-  if ( srcGeoId.isEmpty() || destGeoId.isEmpty() )
-  {
-    return transformations;
-  }
-
-  QStringList srcSplit = srcGeoId.split( ':' );
-  QStringList destSplit = destGeoId.split( ':' );
-
-  if ( srcSplit.size() < 2 || destSplit.size() < 2 )
-  {
-    return transformations;
-  }
-
-  int srcAuthCode = srcSplit.at( 1 ).toInt();
-  int destAuthCode = destSplit.at( 1 ).toInt();
-
-  if ( srcAuthCode == destAuthCode )
-  {
-    return transformations; //crs have the same datum
-  }
-
-  QList<int> directTransforms;
-  searchDatumTransform( QStringLiteral( "SELECT coord_op_code FROM tbl_datum_transform WHERE source_crs_code=%1 AND target_crs_code=%2 ORDER BY deprecated ASC,preferred DESC" ).arg( srcAuthCode ).arg( destAuthCode ),
-                        directTransforms );
-  QList<int> reverseDirectTransforms;
-  searchDatumTransform( QStringLiteral( "SELECT coord_op_code FROM tbl_datum_transform WHERE source_crs_code = %1 AND target_crs_code=%2 ORDER BY deprecated ASC,preferred DESC" ).arg( destAuthCode ).arg( srcAuthCode ),
-                        reverseDirectTransforms );
-  QList<int> srcToWgs84;
-  searchDatumTransform( QStringLiteral( "SELECT coord_op_code FROM tbl_datum_transform WHERE (source_crs_code=%1 AND target_crs_code=%2) OR (source_crs_code=%2 AND target_crs_code=%1) ORDER BY deprecated ASC,preferred DESC" ).arg( srcAuthCode ).arg( 4326 ),
-                        srcToWgs84 );
-  QList<int> destToWgs84;
-  searchDatumTransform( QStringLiteral( "SELECT coord_op_code FROM tbl_datum_transform WHERE (source_crs_code=%1 AND target_crs_code=%2) OR (source_crs_code=%2 AND target_crs_code=%1) ORDER BY deprecated ASC,preferred DESC" ).arg( destAuthCode ).arg( 4326 ),
-                        destToWgs84 );
-
-  //add direct datum transformations
-  for ( int transform : qgis::as_const( directTransforms ) )
-  {
-    transformations.push_back( QgsDatumTransform::TransformPair( transform, -1 ) );
-  }
-
-  //add direct datum transformations
-  for ( int transform : qgis::as_const( directTransforms ) )
-  {
-    transformations.push_back( QgsDatumTransform::TransformPair( -1, transform ) );
-  }
-
-  for ( int srcTransform : qgis::as_const( srcToWgs84 ) )
-  {
-    for ( int destTransform : qgis::as_const( destToWgs84 ) )
-    {
-      transformations.push_back( QgsDatumTransform::TransformPair( srcTransform, destTransform ) );
-    }
-  }
-
-  return transformations;
-}
-
-void QgsCoordinateTransform::searchDatumTransform( const QString &sql, QList< int > &transforms )
-{
-  sqlite3_database_unique_ptr database;
-  int openResult = database.open_v2( QgsApplication::srsDatabaseFilePath(), SQLITE_OPEN_READONLY, nullptr );
-  if ( openResult != SQLITE_OK )
-  {
-    return;
-  }
-
-  sqlite3_statement_unique_ptr statement;
-  int prepareRes;
-  statement = database.prepare( sql, prepareRes );
-  if ( prepareRes != SQLITE_OK )
-  {
-    return;
-  }
-
-  QString cOpCode;
-  while ( statement.step() == SQLITE_ROW )
-  {
-    cOpCode = statement.columnAsText( 0 );
-    transforms.push_back( cOpCode.toInt() );
-  }
-}
-
 bool QgsCoordinateTransform::setFromCache( const QgsCoordinateReferenceSystem &src, const QgsCoordinateReferenceSystem &dest, int srcDatumTransform, int destDatumTransform )
 {
   if ( !src.isValid() || !dest.isValid() )
@@ -833,61 +742,6 @@ void QgsCoordinateTransform::addToCache()
   sCacheLock.unlock();
 }
 
-QString QgsCoordinateTransform::datumTransformToProj( int datumTransform )
-{
-  return QgsCoordinateTransformPrivate::datumTransformString( datumTransform );
-}
-
-int QgsCoordinateTransform::projStringToDatumTransformId( const QString &string )
-{
-  return QgsCoordinateTransformPrivate::transformIdFromString( string );
-}
-
-QgsDatumTransform::TransformInfo QgsCoordinateTransform::datumTransformInfo( int datumTransform )
-{
-  QgsDatumTransform::TransformInfo info;
-
-  sqlite3_database_unique_ptr database;
-  int openResult = database.open_v2( QgsApplication::srsDatabaseFilePath(), SQLITE_OPEN_READONLY, nullptr );
-  if ( openResult != SQLITE_OK )
-  {
-    return info;
-  }
-
-  sqlite3_statement_unique_ptr statement;
-  QString sql = QStringLiteral( "SELECT epsg_nr,source_crs_code,target_crs_code,remarks,scope,preferred,deprecated FROM tbl_datum_transform WHERE coord_op_code=%1" ).arg( datumTransform );
-  int prepareRes;
-  statement = database.prepare( sql, prepareRes );
-  if ( prepareRes != SQLITE_OK )
-  {
-    return info;
-  }
-
-  int srcCrsId, destCrsId;
-  if ( statement.step() != SQLITE_ROW )
-  {
-    return info;
-  }
-
-  info.datumTransformId = datumTransform;
-  info.epsgCode = statement.columnAsInt64( 0 );
-  srcCrsId = statement.columnAsInt64( 1 );
-  destCrsId = statement.columnAsInt64( 2 );
-  info.remarks = statement.columnAsText( 3 );
-  info.scope = statement.columnAsText( 4 );
-  info.preferred = statement.columnAsInt64( 5 ) != 0;
-  info.deprecated = statement.columnAsInt64( 6 ) != 0;
-
-  QgsCoordinateReferenceSystem srcCrs = QgsCoordinateReferenceSystem::fromOgcWmsCrs( QStringLiteral( "EPSG:%1" ).arg( srcCrsId ) );
-  info.sourceCrsDescription = srcCrs.description();
-  info.sourceCrsAuthId = srcCrs.authid();
-  QgsCoordinateReferenceSystem destCrs = QgsCoordinateReferenceSystem::fromOgcWmsCrs( QStringLiteral( "EPSG:%1" ).arg( destCrsId ) );
-  info.destinationCrsDescription = destCrs.description();
-  info.destinationCrsAuthId = destCrs.authid();
-
-  return info;
-}
-
 int QgsCoordinateTransform::sourceDatumTransformId() const
 {
   return d->mSourceDatumTransform;

src/core/qgscoordinatetransform.h

@@ -44,6 +44,9 @@ class QgsProject;
 * operations are from the perspective of the layer. For example, a forward transformation
 * transforms coordinates from the layer's coordinate system to the map canvas.
 * \note Since QGIS 3.0 QgsCoordinateReferenceSystem objects are implicitly shared.
+*
+* \see QgsDatumTransform
+* \see QgsCoordinateTransformContext
 */
 class CORE_EXPORT QgsCoordinateTransform
 {
@@ -312,38 +315,6 @@ class CORE_EXPORT QgsCoordinateTransform
      */
     bool isShortCircuited() const;
 
-    /**
-     * Returns a list of datum transformations which are available for the given \a source and \a destination CRS.
-     * \see datumTransformToProj()
-     * \see datumTransformInfo()
-     */
-    static QList< QgsDatumTransform::TransformPair > datumTransformations( const QgsCoordinateReferenceSystem &source, const QgsCoordinateReferenceSystem &destination );
-
-    /**
-     * Returns a proj string representing the specified \a datumTransformId datum transform ID.
-     * \see datumTransformations()
-     * \see datumTransformInfo()
-     * \see projStringToDatumTransformId()
-     */
-    static QString datumTransformToProj( int datumTransformId );
-
-    /**
-     * Returns the datum transform ID corresponding to a specified proj \a string.
-     * Returns -1 if matching datum ID was not found.
-     * \see datumTransformToProj()
-     * \since QGIS 3.0
-     */
-    static int projStringToDatumTransformId( const QString &string );
-
-    /**
-     * Returns detailed information about the specified \a datumTransformId.
-     * If \a datumTransformId was not a valid transform ID, a TransformInfo with TransformInfo::datumTransformId of
-     * -1 will be returned.
-     * \see datumTransformations()
-     * \see datumTransformToProj()
-    */
-    static QgsDatumTransform::TransformInfo datumTransformInfo( int datumTransformId );
-
     /**
      * Returns the ID of the datum transform to use when projecting from the source
      * CRS.
@@ -406,8 +377,6 @@ class CORE_EXPORT QgsCoordinateTransform
 
   private:
 
-    static void searchDatumTransform( const QString &sql, QList< int > &transforms );
-
     mutable QExplicitlySharedDataPointer<QgsCoordinateTransformPrivate> d;
 
     //! Transform context

src/core/qgscoordinatetransform_p.cpp

@@ -140,7 +140,7 @@ bool QgsCoordinateTransformPrivate::initialize()
   }
   if ( sourceDatumTransform != -1 )
   {
-    mSourceProjString += ( ' ' + datumTransformString( sourceDatumTransform ) );
+    mSourceProjString += ( ' ' + QgsDatumTransform::datumTransformToProj( sourceDatumTransform ) );
   }
 
   mDestProjString = mDestCRS.toProj4();
@@ -150,7 +150,7 @@ bool QgsCoordinateTransformPrivate::initialize()
   }
   if ( destDatumTransform != -1 )
   {
-    mDestProjString += ( ' ' +  datumTransformString( destDatumTransform ) );
+    mDestProjString += ( ' ' +  QgsDatumTransform::datumTransformToProj( destDatumTransform ) );
   }
 
   if ( !useDefaultDatumTransform )
@@ -284,114 +284,6 @@ QString QgsCoordinateTransformPrivate::stripDatumTransform( const QString &proj4
   return newProjString;
 }
 
-QString QgsCoordinateTransformPrivate::datumTransformString( int datumTransform )
-{
-  QString transformString;
-
-  sqlite3_database_unique_ptr database;
-  int openResult = database.open_v2( QgsApplication::srsDatabaseFilePath(), SQLITE_OPEN_READONLY, nullptr );
-  if ( openResult != SQLITE_OK )
-  {
-    return transformString;
-  }
-
-  sqlite3_statement_unique_ptr statement;
-  QString sql = QStringLiteral( "SELECT coord_op_method_code,p1,p2,p3,p4,p5,p6,p7 FROM tbl_datum_transform WHERE coord_op_code=%1" ).arg( datumTransform );
-  int prepareRes;
-  statement = database.prepare( sql, prepareRes );
-  if ( prepareRes != SQLITE_OK )
-  {
-    return transformString;
-  }
-
-  if ( statement.step() == SQLITE_ROW )
-  {
-    //coord_op_methode_code
-    int methodCode = statement.columnAsInt64( 0 );
-    if ( methodCode == 9615 ) //ntv2
-    {
-      transformString = "+nadgrids=" + statement.columnAsText( 1 );
-    }
-    else if ( methodCode == 9603 || methodCode == 9606 || methodCode == 9607 )
-    {
-      transformString += QLatin1String( "+towgs84=" );
-      double p1 = statement.columnAsDouble( 1 );
-      double p2 = statement.columnAsDouble( 2 );
-      double p3 = statement.columnAsDouble( 3 );
-      double p4 = statement.columnAsDouble( 4 );
-      double p5 = statement.columnAsDouble( 5 );
-      double p6 = statement.columnAsDouble( 6 );
-      double p7 = statement.columnAsDouble( 7 );
-      if ( methodCode == 9603 ) //3 parameter transformation
-      {
-        transformString += QStringLiteral( "%1,%2,%3" ).arg( QString::number( p1 ), QString::number( p2 ), QString::number( p3 ) );
-      }
-      else //7 parameter transformation
-      {
-        transformString += QStringLiteral( "%1,%2,%3,%4,%5,%6,%7" ).arg( QString::number( p1 ), QString::number( p2 ), QString::number( p3 ), QString::number( p4 ), QString::number( p5 ), QString::number( p6 ), QString::number( p7 ) );
-      }
-    }
-  }
-
-  return transformString;
-}
-
-int QgsCoordinateTransformPrivate::transformIdFromString( const QString &string )
-{
-  sqlite3_database_unique_ptr database;
-  int openResult = database.open_v2( QgsApplication::srsDatabaseFilePath(), SQLITE_OPEN_READONLY, nullptr );
-  if ( openResult != SQLITE_OK )
-  {
-    return -1;
-  }
-
-  sqlite3_statement_unique_ptr statement;
-  QString sql = QStringLiteral( "SELECT coord_op_method_code,p1,p2,p3,p4,p5,p6,p7,coord_op_code FROM tbl_datum_transform" );
-  int prepareRes;
-  statement = database.prepare( sql, prepareRes );
-  if ( prepareRes != SQLITE_OK )
-  {
-    return -1;
-  }
-
-  while ( statement.step() == SQLITE_ROW )
-  {
-    QString transformString;
-    //coord_op_methode_code
-    int methodCode = statement.columnAsInt64( 0 );
-    if ( methodCode == 9615 ) //ntv2
-    {
-      transformString = "+nadgrids=" + statement.columnAsText( 1 );
-    }
-    else if ( methodCode == 9603 || methodCode == 9606 || methodCode == 9607 )
-    {
-      transformString += QLatin1String( "+towgs84=" );
-      double p1 = statement.columnAsDouble( 1 );
-      double p2 = statement.columnAsDouble( 2 );
-      double p3 = statement.columnAsDouble( 3 );
-      double p4 = statement.columnAsDouble( 4 );
-      double p5 = statement.columnAsDouble( 5 );
-      double p6 = statement.columnAsDouble( 6 );
-      double p7 = statement.columnAsDouble( 7 );
-      if ( methodCode == 9603 ) //3 parameter transformation
-      {
-        transformString += QStringLiteral( "%1,%2,%3" ).arg( QString::number( p1 ), QString::number( p2 ), QString::number( p3 ) );
-      }
-      else //7 parameter transformation
-      {
-        transformString += QStringLiteral( "%1,%2,%3,%4,%5,%6,%7" ).arg( QString::number( p1 ), QString::number( p2 ), QString::number( p3 ), QString::number( p4 ), QString::number( p5 ), QString::number( p6 ), QString::number( p7 ) );
-      }
-    }
-
-    if ( transformString.compare( string, Qt::CaseInsensitive ) == 0 )
-    {
-      return statement.columnAsInt64( 8 );
-    }
-  }
-
-  return -1;
-}
-
 void QgsCoordinateTransformPrivate::addNullGridShifts( QString &srcProjString, QString &destProjString,
     int sourceDatumTransform, int destinationDatumTransform ) const
 {

src/core/qgscoordinatetransform_p.h

@@ -128,21 +128,6 @@ class QgsCoordinateTransformPrivate : public QSharedData
     QReadWriteLock mProjLock;
     QMap < uintptr_t, QPair< projPJ, projPJ > > mProjProjections;
 
-    /**
-     * Returns the proj transform string corresponding to a
-     * datum transform ID.
-     * \see transformIdFromString()
-     */
-    static QString datumTransformString( int transformId );
-
-    /**
-     * Attempts to match a proj datum transform string to a datum ID.
-     * Returns -1 if datum ID was not found.
-     * \see datumTransformString()
-     * \since QGIS 3.0
-     */
-    static int transformIdFromString( const QString &string );
-
   private:
 
     //! Removes +nadgrids and +towgs84 from proj4 string

src/core/qgscoordinatetransformcontext.cpp

@@ -203,7 +203,7 @@ bool QgsCoordinateTransformContext::readXml( const QDomElement &element, const Q
     //warn if value1 or value2 is non-empty, yet no matching transform was found
     if ( !value1.isEmpty() )
     {
-      datumId1 = QgsCoordinateTransform::projStringToDatumTransformId( value1 );
+      datumId1 = QgsDatumTransform::projStringToDatumTransformId( value1 );
       if ( datumId1 < 0 )
       {
         result = false;
@@ -212,7 +212,7 @@ bool QgsCoordinateTransformContext::readXml( const QDomElement &element, const Q
     }
     if ( !value2.isEmpty() )
     {
-      datumId2 = QgsCoordinateTransform::projStringToDatumTransformId( value2 );
+      datumId2 = QgsDatumTransform::projStringToDatumTransformId( value2 );
       if ( datumId2 < 0 )
       {
         result = false;
@@ -271,8 +271,8 @@ void QgsCoordinateTransformContext::writeXml( QDomElement &element, const QgsRea
     QDomElement transformElem = element.ownerDocument().createElement( QStringLiteral( "srcDest" ) );
     transformElem.setAttribute( QStringLiteral( "source" ), it.key().first );
     transformElem.setAttribute( QStringLiteral( "dest" ), it.key().second );
-    transformElem.setAttribute( QStringLiteral( "sourceTransform" ), it.value().sourceTransformId < 0 ? QString() : QgsCoordinateTransform::datumTransformToProj( it.value().sourceTransformId ) );
+    transformElem.setAttribute( QStringLiteral( "sourceTransform" ), it.value().sourceTransformId < 0 ? QString() : QgsDatumTransform::datumTransformToProj( it.value().sourceTransformId ) );
-    transformElem.setAttribute( QStringLiteral( "destTransform" ), it.value().destinationTransformId < 0 ? QString() : QgsCoordinateTransform::datumTransformToProj( it.value().destinationTransformId ) );
+    transformElem.setAttribute( QStringLiteral( "destTransform" ), it.value().destinationTransformId < 0 ? QString() : QgsDatumTransform::datumTransformToProj( it.value().destinationTransformId ) );
     contextElem.appendChild( transformElem );
   }
 
@@ -334,7 +334,7 @@ void QgsCoordinateTransformContext::readSettings()
       }
 
       QString proj = settings.value( *pkeyIt ).toString();
-      int datumId = QgsCoordinateTransform::projStringToDatumTransformId( proj );
+      int datumId = QgsDatumTransform::projStringToDatumTransformId( proj );
       if ( pkeyIt->contains( QLatin1String( "srcTransform" ) ) )
       {
         transforms[ qMakePair( srcAuthId, destAuthId )].first = datumId;
@@ -378,11 +378,11 @@ void QgsCoordinateTransformContext::writeSettings()
     int sourceDatumTransform = transformIt.value().sourceTransformId;
     QString sourceDatumProj;
     if ( sourceDatumTransform >= 0 )
-      sourceDatumProj = QgsCoordinateTransform::datumTransformToProj( sourceDatumTransform );
+      sourceDatumProj = QgsDatumTransform::datumTransformToProj( sourceDatumTransform );
     int destinationDatumTransform = transformIt.value().destinationTransformId;
     QString destinationDatumProj;
     if ( destinationDatumTransform >= 0 )
-      destinationDatumProj = QgsCoordinateTransform::datumTransformToProj( destinationDatumTransform );
+      destinationDatumProj = QgsDatumTransform::datumTransformToProj( destinationDatumTransform );
 
     settings.setValue( srcAuthId + "//" + destAuthId + "_srcTransform", sourceDatumProj );
     settings.setValue( srcAuthId + "//" + destAuthId + "_destTransform", destinationDatumProj );

src/core/qgscoordinatetransformcontext.h

@@ -53,6 +53,9 @@ class QDomElement;
  *
  * \note QgsCoordinateTransformContext objects are implicitly shared.
  *
+ * \see QgsDatumTransform
+ * \see QgsCoordinateTransform
+ *
  * \since QGIS 3.0
 */
 

src/core/qgsdatumtransform.cpp

@@ -0,0 +1,263 @@
+/***************************************************************************
+               qgsdatumtransform.cpp
+               ------------------------
+    begin                : Dec 2017
+    copyright            : (C) 2017 Nyall Dawson
+    email                : nyall dot dawson at gmail dot com
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+#include "qgsdatumtransform.h"
+#include "qgscoordinatereferencesystem.h"
+#include "qgsapplication.h"
+#include "qgssqliteutils.h"
+#include <sqlite3.h>
+
+QList< QgsDatumTransform::TransformPair > QgsDatumTransform::datumTransformations( const QgsCoordinateReferenceSystem &srcCRS, const QgsCoordinateReferenceSystem &destCRS )
+{
+  QList< QgsDatumTransform::TransformPair > transformations;
+
+  QString srcGeoId = srcCRS.geographicCrsAuthId();
+  QString destGeoId = destCRS.geographicCrsAuthId();
+
+  if ( srcGeoId.isEmpty() || destGeoId.isEmpty() )
+  {
+    return transformations;
+  }
+
+  QStringList srcSplit = srcGeoId.split( ':' );
+  QStringList destSplit = destGeoId.split( ':' );
+
+  if ( srcSplit.size() < 2 || destSplit.size() < 2 )
+  {
+    return transformations;
+  }
+
+  int srcAuthCode = srcSplit.at( 1 ).toInt();
+  int destAuthCode = destSplit.at( 1 ).toInt();
+
+  if ( srcAuthCode == destAuthCode )
+  {
+    return transformations; //crs have the same datum
+  }
+
+  QList<int> directTransforms;
+  searchDatumTransform( QStringLiteral( "SELECT coord_op_code FROM tbl_datum_transform WHERE source_crs_code=%1 AND target_crs_code=%2 ORDER BY deprecated ASC,preferred DESC" ).arg( srcAuthCode ).arg( destAuthCode ),
+                        directTransforms );
+  QList<int> reverseDirectTransforms;
+  searchDatumTransform( QStringLiteral( "SELECT coord_op_code FROM tbl_datum_transform WHERE source_crs_code = %1 AND target_crs_code=%2 ORDER BY deprecated ASC,preferred DESC" ).arg( destAuthCode ).arg( srcAuthCode ),
+                        reverseDirectTransforms );
+  QList<int> srcToWgs84;
+  searchDatumTransform( QStringLiteral( "SELECT coord_op_code FROM tbl_datum_transform WHERE (source_crs_code=%1 AND target_crs_code=%2) OR (source_crs_code=%2 AND target_crs_code=%1) ORDER BY deprecated ASC,preferred DESC" ).arg( srcAuthCode ).arg( 4326 ),
+                        srcToWgs84 );
+  QList<int> destToWgs84;
+  searchDatumTransform( QStringLiteral( "SELECT coord_op_code FROM tbl_datum_transform WHERE (source_crs_code=%1 AND target_crs_code=%2) OR (source_crs_code=%2 AND target_crs_code=%1) ORDER BY deprecated ASC,preferred DESC" ).arg( destAuthCode ).arg( 4326 ),
+                        destToWgs84 );
+
+  //add direct datum transformations
+  for ( int transform : qgis::as_const( directTransforms ) )
+  {
+    transformations.push_back( QgsDatumTransform::TransformPair( transform, -1 ) );
+  }
+
+  //add direct datum transformations
+  for ( int transform : qgis::as_const( directTransforms ) )
+  {
+    transformations.push_back( QgsDatumTransform::TransformPair( -1, transform ) );
+  }
+
+  for ( int srcTransform : qgis::as_const( srcToWgs84 ) )
+  {
+    for ( int destTransform : qgis::as_const( destToWgs84 ) )
+    {
+      transformations.push_back( QgsDatumTransform::TransformPair( srcTransform, destTransform ) );
+    }
+  }
+
+  return transformations;
+}
+
+void QgsDatumTransform::searchDatumTransform( const QString &sql, QList< int > &transforms )
+{
+  sqlite3_database_unique_ptr database;
+  int openResult = database.open_v2( QgsApplication::srsDatabaseFilePath(), SQLITE_OPEN_READONLY, nullptr );
+  if ( openResult != SQLITE_OK )
+  {
+    return;
+  }
+
+  sqlite3_statement_unique_ptr statement;
+  int prepareRes;
+  statement = database.prepare( sql, prepareRes );
+  if ( prepareRes != SQLITE_OK )
+  {
+    return;
+  }
+
+  QString cOpCode;
+  while ( statement.step() == SQLITE_ROW )
+  {
+    cOpCode = statement.columnAsText( 0 );
+    transforms.push_back( cOpCode.toInt() );
+  }
+}
+
+QString QgsDatumTransform::datumTransformToProj( int datumTransform )
+{
+  QString transformString;
+
+  sqlite3_database_unique_ptr database;
+  int openResult = database.open_v2( QgsApplication::srsDatabaseFilePath(), SQLITE_OPEN_READONLY, nullptr );
+  if ( openResult != SQLITE_OK )
+  {
+    return transformString;
+  }
+
+  sqlite3_statement_unique_ptr statement;
+  QString sql = QStringLiteral( "SELECT coord_op_method_code,p1,p2,p3,p4,p5,p6,p7 FROM tbl_datum_transform WHERE coord_op_code=%1" ).arg( datumTransform );
+  int prepareRes;
+  statement = database.prepare( sql, prepareRes );
+  if ( prepareRes != SQLITE_OK )
+  {
+    return transformString;
+  }
+
+  if ( statement.step() == SQLITE_ROW )
+  {
+    //coord_op_methode_code
+    int methodCode = statement.columnAsInt64( 0 );
+    if ( methodCode == 9615 ) //ntv2
+    {
+      transformString = "+nadgrids=" + statement.columnAsText( 1 );
+    }
+    else if ( methodCode == 9603 || methodCode == 9606 || methodCode == 9607 )
+    {
+      transformString += QLatin1String( "+towgs84=" );
+      double p1 = statement.columnAsDouble( 1 );
+      double p2 = statement.columnAsDouble( 2 );
+      double p3 = statement.columnAsDouble( 3 );
+      double p4 = statement.columnAsDouble( 4 );
+      double p5 = statement.columnAsDouble( 5 );
+      double p6 = statement.columnAsDouble( 6 );
+      double p7 = statement.columnAsDouble( 7 );
+      if ( methodCode == 9603 ) //3 parameter transformation
+      {
+        transformString += QStringLiteral( "%1,%2,%3" ).arg( QString::number( p1 ), QString::number( p2 ), QString::number( p3 ) );
+      }
+      else //7 parameter transformation
+      {
+        transformString += QStringLiteral( "%1,%2,%3,%4,%5,%6,%7" ).arg( QString::number( p1 ), QString::number( p2 ), QString::number( p3 ), QString::number( p4 ), QString::number( p5 ), QString::number( p6 ), QString::number( p7 ) );
+      }
+    }
+  }
+
+  return transformString;
+}
+
+int QgsDatumTransform::projStringToDatumTransformId( const QString &string )
+{
+  sqlite3_database_unique_ptr database;
+  int openResult = database.open_v2( QgsApplication::srsDatabaseFilePath(), SQLITE_OPEN_READONLY, nullptr );
+  if ( openResult != SQLITE_OK )
+  {
+    return -1;
+  }
+
+  sqlite3_statement_unique_ptr statement;
+  QString sql = QStringLiteral( "SELECT coord_op_method_code,p1,p2,p3,p4,p5,p6,p7,coord_op_code FROM tbl_datum_transform" );
+  int prepareRes;
+  statement = database.prepare( sql, prepareRes );
+  if ( prepareRes != SQLITE_OK )
+  {
+    return -1;
+  }
+
+  while ( statement.step() == SQLITE_ROW )
+  {
+    QString transformString;
+    //coord_op_methode_code
+    int methodCode = statement.columnAsInt64( 0 );
+    if ( methodCode == 9615 ) //ntv2
+    {
+      transformString = "+nadgrids=" + statement.columnAsText( 1 );
+    }
+    else if ( methodCode == 9603 || methodCode == 9606 || methodCode == 9607 )
+    {
+      transformString += QLatin1String( "+towgs84=" );
+      double p1 = statement.columnAsDouble( 1 );
+      double p2 = statement.columnAsDouble( 2 );
+      double p3 = statement.columnAsDouble( 3 );
+      double p4 = statement.columnAsDouble( 4 );
+      double p5 = statement.columnAsDouble( 5 );
+      double p6 = statement.columnAsDouble( 6 );
+      double p7 = statement.columnAsDouble( 7 );
+      if ( methodCode == 9603 ) //3 parameter transformation
+      {
+        transformString += QStringLiteral( "%1,%2,%3" ).arg( QString::number( p1 ), QString::number( p2 ), QString::number( p3 ) );
+      }
+      else //7 parameter transformation
+      {
+        transformString += QStringLiteral( "%1,%2,%3,%4,%5,%6,%7" ).arg( QString::number( p1 ), QString::number( p2 ), QString::number( p3 ), QString::number( p4 ), QString::number( p5 ), QString::number( p6 ), QString::number( p7 ) );
+      }
+    }
+
+    if ( transformString.compare( string, Qt::CaseInsensitive ) == 0 )
+    {
+      return statement.columnAsInt64( 8 );
+    }
+  }
+
+  return -1;
+}
+
+QgsDatumTransform::TransformInfo QgsDatumTransform::datumTransformInfo( int datumTransform )
+{
+  QgsDatumTransform::TransformInfo info;
+
+  sqlite3_database_unique_ptr database;
+  int openResult = database.open_v2( QgsApplication::srsDatabaseFilePath(), SQLITE_OPEN_READONLY, nullptr );
+  if ( openResult != SQLITE_OK )
+  {
+    return info;
+  }
+
+  sqlite3_statement_unique_ptr statement;
+  QString sql = QStringLiteral( "SELECT epsg_nr,source_crs_code,target_crs_code,remarks,scope,preferred,deprecated FROM tbl_datum_transform WHERE coord_op_code=%1" ).arg( datumTransform );
+  int prepareRes;
+  statement = database.prepare( sql, prepareRes );
+  if ( prepareRes != SQLITE_OK )
+  {
+    return info;
+  }
+
+  int srcCrsId, destCrsId;
+  if ( statement.step() != SQLITE_ROW )
+  {
+    return info;
+  }
+
+  info.datumTransformId = datumTransform;
+  info.epsgCode = statement.columnAsInt64( 0 );
+  srcCrsId = statement.columnAsInt64( 1 );
+  destCrsId = statement.columnAsInt64( 2 );
+  info.remarks = statement.columnAsText( 3 );
+  info.scope = statement.columnAsText( 4 );
+  info.preferred = statement.columnAsInt64( 5 ) != 0;
+  info.deprecated = statement.columnAsInt64( 6 ) != 0;
+
+  QgsCoordinateReferenceSystem srcCrs = QgsCoordinateReferenceSystem::fromOgcWmsCrs( QStringLiteral( "EPSG:%1" ).arg( srcCrsId ) );
+  info.sourceCrsDescription = srcCrs.description();
+  info.sourceCrsAuthId = srcCrs.authid();
+  QgsCoordinateReferenceSystem destCrs = QgsCoordinateReferenceSystem::fromOgcWmsCrs( QStringLiteral( "EPSG:%1" ).arg( destCrsId ) );
+  info.destinationCrsDescription = destCrs.description();
+  info.destinationCrsAuthId = destCrs.authid();
+
+  return info;
+}

src/core/qgsdatumtransform.h

@@ -20,9 +20,16 @@
 #include "qgis_core.h"
 #include <QString>
 
+class QgsCoordinateReferenceSystem;
+
+
 /**
  * Contains methods and classes relating the datum transformations.
  * \ingroup core
+ *
+ * \see QgsCoordinateTransformContext
+ * \see QgsCoordinateTransform
+ *
  * \since QGIS 3.0
  */
 class CORE_EXPORT QgsDatumTransform
@@ -107,6 +114,43 @@ class CORE_EXPORT QgsDatumTransform
       bool deprecated = false;
 
     };
+
+    /**
+     * Returns a list of datum transformations which are available for the given \a source and \a destination CRS.
+     * \see datumTransformToProj()
+     * \see datumTransformInfo()
+     */
+    static QList< QgsDatumTransform::TransformPair > datumTransformations( const QgsCoordinateReferenceSystem &source, const QgsCoordinateReferenceSystem &destination );
+
+    /**
+     * Returns a proj string representing the specified \a datumTransformId datum transform ID.
+     * \see datumTransformations()
+     * \see datumTransformInfo()
+     * \see projStringToDatumTransformId()
+     */
+    static QString datumTransformToProj( int datumTransformId );
+
+    /**
+     * Returns the datum transform ID corresponding to a specified proj \a string.
+     * Returns -1 if matching datum ID was not found.
+     * \see datumTransformToProj()
+     */
+    static int projStringToDatumTransformId( const QString &string );
+
+    /**
+     * Returns detailed information about the specified \a datumTransformId.
+     * If \a datumTransformId was not a valid transform ID, a TransformInfo with TransformInfo::datumTransformId of
+     * -1 will be returned.
+     * \see datumTransformations()
+     * \see datumTransformToProj()
+    */
+    static QgsDatumTransform::TransformInfo datumTransformInfo( int datumTransformId );
+
+  private:
+
+    static void searchDatumTransform( const QString &sql, QList< int > &transforms );
+
+
 };
 
 #endif // QGSDATUMTRANSFORM_H

src/gui/qgsdatumtransformdialog.cpp

@@ -46,7 +46,7 @@ QgsDatumTransformDialog::QgsDatumTransformDialog( const QgsCoordinateReferenceSy
   //get list of datum transforms
   mSourceCrs = sourceCrs;
   mDestinationCrs = destinationCrs;
-  mDatumTransforms = QgsCoordinateTransform::datumTransformations( sourceCrs, destinationCrs );
+  mDatumTransforms = QgsDatumTransform::datumTransformations( sourceCrs, destinationCrs );
 
   QApplication::setOverrideCursor( Qt::ArrowCursor );
 
@@ -84,10 +84,10 @@ void QgsDatumTransformDialog::load( const QPair<int, int> &selectedDatumTransfor
       if ( nr == -1 )
         continue;
 
-      item->setText( i, QgsCoordinateTransform::datumTransformToProj( nr ) );
+      item->setText( i, QgsDatumTransform::datumTransformToProj( nr ) );
 
       //Describe datums in a tooltip
-      QgsDatumTransform::TransformInfo info = QgsCoordinateTransform::datumTransformInfo( nr );
+      QgsDatumTransform::TransformInfo info = QgsDatumTransform::datumTransformInfo( nr );
       if ( info.datumTransformId == -1 )
         continue;
 
@@ -266,7 +266,7 @@ void QgsDatumTransformDialog::mDatumTransformTreeWidget_currentItemChanged( QTre
 void QgsDatumTransformDialog::setSourceCrs( const QgsCoordinateReferenceSystem &sourceCrs )
 {
   mSourceCrs = sourceCrs;
-  mDatumTransforms = QgsCoordinateTransform::datumTransformations( mSourceCrs, mDestinationCrs );
+  mDatumTransforms = QgsDatumTransform::datumTransformations( mSourceCrs, mDestinationCrs );
   load();
   setOKButtonEnabled();
 }
@@ -274,7 +274,7 @@ void QgsDatumTransformDialog::setSourceCrs( const QgsCoordinateReferenceSystem &
 void QgsDatumTransformDialog::setDestinationCrs( const QgsCoordinateReferenceSystem &destinationCrs )
 {
   mDestinationCrs = destinationCrs;
-  mDatumTransforms = QgsCoordinateTransform::datumTransformations( mSourceCrs, mDestinationCrs );
+  mDatumTransforms = QgsDatumTransform::datumTransformations( mSourceCrs, mDestinationCrs );
   load();
   setOKButtonEnabled();
 }

tests/src/python/test_qgscoordinatetransform.py

@@ -18,6 +18,7 @@ from qgis.core import (QgsRectangle,
                        QgsCoordinateReferenceSystem,
                        QgsCoordinateTransform,
                        QgsCoordinateTransformContext,
+                       QgsDatumTransform,
                        QgsProject)
 from qgis.testing import start_app, unittest
 
@@ -209,27 +210,27 @@ class TestQgsCoordinateTransform(unittest.TestCase):
 
     def testTransformInfo(self):
         # hopefully this transform is available on all platforms!
-        transforms = QgsCoordinateTransform.datumTransformations(QgsCoordinateReferenceSystem(4613), QgsCoordinateReferenceSystem(4326))
+        transforms = QgsDatumTransform.datumTransformations(QgsCoordinateReferenceSystem(4613), QgsCoordinateReferenceSystem(4326))
         self.assertTrue(len(transforms) > 0)
-        self.assertIn('+towgs84=-403,684,41', [QgsCoordinateTransform.datumTransformToProj(t.sourceTransformId) for t in transforms])
+        self.assertIn('+towgs84=-403,684,41', [QgsDatumTransform.datumTransformToProj(t.sourceTransformId) for t in transforms])
-        self.assertIn('+towgs84=-403,684,41', [QgsCoordinateTransform.datumTransformToProj(t.destinationTransformId) for t in transforms])
+        self.assertIn('+towgs84=-403,684,41', [QgsDatumTransform.datumTransformToProj(t.destinationTransformId) for t in transforms])
-        self.assertIn('EPSG:4613', [QgsCoordinateTransform.datumTransformInfo(t.destinationTransformId).sourceCrsAuthId for t in
+        self.assertIn('EPSG:4613', [QgsDatumTransform.datumTransformInfo(t.destinationTransformId).sourceCrsAuthId for t in
                                     transforms])
-        self.assertIn('EPSG:4326', [QgsCoordinateTransform.datumTransformInfo(t.destinationTransformId).destinationCrsAuthId for t in
+        self.assertIn('EPSG:4326', [QgsDatumTransform.datumTransformInfo(t.destinationTransformId).destinationCrsAuthId for t in
                                     transforms])
 
     def testStringToTransformId(self):
         """
         Test converting proj strings to corresponding datum IDs
         """
-        self.assertEqual(QgsCoordinateTransform.projStringToDatumTransformId(''), -1)
+        self.assertEqual(QgsDatumTransform.projStringToDatumTransformId(''), -1)
-        self.assertEqual(QgsCoordinateTransform.projStringToDatumTransformId('not'), -1)
+        self.assertEqual(QgsDatumTransform.projStringToDatumTransformId('not'), -1)
         test_string = '+towgs84=-403,684,41'
-        id = QgsCoordinateTransform.projStringToDatumTransformId(test_string)
+        id = QgsDatumTransform.projStringToDatumTransformId(test_string)
         self.assertNotEqual(id, -1)
-        string = QgsCoordinateTransform.datumTransformToProj(id)
+        string = QgsDatumTransform.datumTransformToProj(id)
         self.assertEqual(string, test_string)
-        self.assertEqual(QgsCoordinateTransform.projStringToDatumTransformId(test_string.upper()), id)
+        self.assertEqual(QgsDatumTransform.projStringToDatumTransformId(test_string.upper()), id)
 
 
 if __name__ == '__main__':

tests/src/python/test_qgscoordinatetransformcontext.py

@@ -302,15 +302,15 @@ class TestQgsCoordinateTransformContext(unittest.TestCase):
         # setup a context
         context = QgsCoordinateTransformContext()
 
-        source_id_1 = QgsCoordinateTransform.datumTransformations(QgsCoordinateReferenceSystem(4204),
+        source_id_1 = QgsDatumTransform.datumTransformations(QgsCoordinateReferenceSystem(4204),
-                                                                  QgsCoordinateReferenceSystem(4326))[0].sourceTransformId
+                                                             QgsCoordinateReferenceSystem(4326))[0].sourceTransformId
-        dest_id_1 = QgsCoordinateTransform.datumTransformations(QgsCoordinateReferenceSystem(4204),
+        dest_id_1 = QgsDatumTransform.datumTransformations(QgsCoordinateReferenceSystem(4204),
-                                                                QgsCoordinateReferenceSystem(4326))[0].destinationTransformId
+                                                           QgsCoordinateReferenceSystem(4326))[0].destinationTransformId
 
-        source_id_2 = QgsCoordinateTransform.datumTransformations(QgsCoordinateReferenceSystem(4205),
+        source_id_2 = QgsDatumTransform.datumTransformations(QgsCoordinateReferenceSystem(4205),
-                                                                  QgsCoordinateReferenceSystem(4326))[0].sourceTransformId
+                                                             QgsCoordinateReferenceSystem(4326))[0].sourceTransformId
-        dest_id_2 = QgsCoordinateTransform.datumTransformations(QgsCoordinateReferenceSystem(4205),
+        dest_id_2 = QgsDatumTransform.datumTransformations(QgsCoordinateReferenceSystem(4205),
-                                                                QgsCoordinateReferenceSystem(4326))[0].destinationTransformId
+                                                           QgsCoordinateReferenceSystem(4326))[0].destinationTransformId
 
         self.assertTrue(context.addSourceDestinationDatumTransform(QgsCoordinateReferenceSystem(4204),
                                                                    QgsCoordinateReferenceSystem(4326), source_id_1, dest_id_1))
@@ -373,15 +373,15 @@ class TestQgsCoordinateTransformContext(unittest.TestCase):
         context = QgsCoordinateTransformContext()
         context.readSettings()
 
-        source_id_1 = QgsCoordinateTransform.datumTransformations(QgsCoordinateReferenceSystem(4204),
+        source_id_1 = QgsDatumTransform.datumTransformations(QgsCoordinateReferenceSystem(4204),
-                                                                  QgsCoordinateReferenceSystem(4326))[0].sourceTransformId
+                                                             QgsCoordinateReferenceSystem(4326))[0].sourceTransformId
-        dest_id_1 = QgsCoordinateTransform.datumTransformations(QgsCoordinateReferenceSystem(4204),
+        dest_id_1 = QgsDatumTransform.datumTransformations(QgsCoordinateReferenceSystem(4204),
-                                                                QgsCoordinateReferenceSystem(4326))[0].destinationTransformId
+                                                           QgsCoordinateReferenceSystem(4326))[0].destinationTransformId
 
-        source_id_2 = QgsCoordinateTransform.datumTransformations(QgsCoordinateReferenceSystem(4205),
+        source_id_2 = QgsDatumTransform.datumTransformations(QgsCoordinateReferenceSystem(4205),
-                                                                  QgsCoordinateReferenceSystem(4326))[0].sourceTransformId
+                                                             QgsCoordinateReferenceSystem(4326))[0].sourceTransformId
-        dest_id_2 = QgsCoordinateTransform.datumTransformations(QgsCoordinateReferenceSystem(4205),
+        dest_id_2 = QgsDatumTransform.datumTransformations(QgsCoordinateReferenceSystem(4205),
-                                                                QgsCoordinateReferenceSystem(4326))[0].destinationTransformId
+                                                           QgsCoordinateReferenceSystem(4326))[0].destinationTransformId
 
         # should be empty
         self.assertEqual(context.sourceDestinationDatumTransforms(), {})