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nyalldawsonnyalldawson
committedDec 15, 2017
Add method to retrieve datum transform ID from a proj string
·
ltr-3_40final-3_0_0
1 parent 43d8a6b commit 3187352

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6 files changed

+107
-1
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6 files changed

+107
-1
lines changed
 

‎python/core/qgscoordinatetransform.sip

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Original file line numberDiff line numberDiff line change
@@ -281,9 +281,19 @@ Default constructor, creates an invalid QgsCoordinateTransform.
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Returns a proj string representing the specified ``datumTransformId`` datum transform ID.
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.. seealso:: :py:func:`datumTransformations()`
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.. seealso:: :py:func:`datumTransformInfo()`
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.. seealso:: :py:func:`projStringToDatumTransformId()`
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:rtype: str
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%End
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static int projStringToDatumTransformId( const QString &string );
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%Docstring
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Returns the datum transform ID corresponding to a specified proj ``string``.
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Returns -1 if matching datum ID was not found.
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.. seealso:: :py:func:`datumTransformToProj()`
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.. versionadded:: 3.0
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:rtype: int
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%End
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struct TransformInfo
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{
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int datumTransformId;

‎src/core/qgscoordinatetransform.cpp

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@@ -816,6 +816,11 @@ QString QgsCoordinateTransform::datumTransformToProj( int datumTransform )
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return QgsCoordinateTransformPrivate::datumTransformString( datumTransform );
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}
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int QgsCoordinateTransform::projStringToDatumTransformId( const QString &string )
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{
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return QgsCoordinateTransformPrivate::transformIdFromString( string );
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}
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QgsCoordinateTransform::TransformInfo QgsCoordinateTransform::datumTransformInfo( int datumTransform )
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{
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TransformInfo info;

‎src/core/qgscoordinatetransform.h

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@@ -363,9 +363,18 @@ class CORE_EXPORT QgsCoordinateTransform
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* Returns a proj string representing the specified \a datumTransformId datum transform ID.
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* \see datumTransformations()
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* \see datumTransformInfo()
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* \see projStringToDatumTransformId()
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*/
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static QString datumTransformToProj( int datumTransformId );
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/**
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* Returns the datum transform ID corresponding to a specified proj \a string.
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* Returns -1 if matching datum ID was not found.
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* \see datumTransformToProj()
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* \since QGIS 3.0
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*/
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static int projStringToDatumTransformId( const QString &string );
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/**
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* Contains datum transform information.
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* \since QGIS 3.0

‎src/core/qgscoordinatetransform_p.cpp

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@@ -341,6 +341,62 @@ QString QgsCoordinateTransformPrivate::datumTransformString( int datumTransform
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return transformString;
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}
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int QgsCoordinateTransformPrivate::transformIdFromString( const QString &string )
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{
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sqlite3_database_unique_ptr database;
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int openResult = database.open_v2( QgsApplication::srsDatabaseFilePath(), SQLITE_OPEN_READONLY, nullptr );
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if ( openResult != SQLITE_OK )
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{
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return -1;
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}
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sqlite3_statement_unique_ptr statement;
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QString sql = QStringLiteral( "SELECT coord_op_method_code,p1,p2,p3,p4,p5,p6,p7,coord_op_code FROM tbl_datum_transform" );
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int prepareRes;
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statement = database.prepare( sql, prepareRes );
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if ( prepareRes != SQLITE_OK )
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{
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return -1;
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}
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while ( statement.step() == SQLITE_ROW )
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{
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QString transformString;
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//coord_op_methode_code
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int methodCode = statement.columnAsInt64( 0 );
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if ( methodCode == 9615 ) //ntv2
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{
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transformString = "+nadgrids=" + statement.columnAsText( 1 );
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}
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else if ( methodCode == 9603 || methodCode == 9606 || methodCode == 9607 )
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{
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transformString += QLatin1String( "+towgs84=" );
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double p1 = statement.columnAsDouble( 1 );
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double p2 = statement.columnAsDouble( 2 );
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double p3 = statement.columnAsDouble( 3 );
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double p4 = statement.columnAsDouble( 4 );
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double p5 = statement.columnAsDouble( 5 );
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double p6 = statement.columnAsDouble( 6 );
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double p7 = statement.columnAsDouble( 7 );
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if ( methodCode == 9603 ) //3 parameter transformation
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{
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transformString += QStringLiteral( "%1,%2,%3" ).arg( QString::number( p1 ), QString::number( p2 ), QString::number( p3 ) );
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}
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else //7 parameter transformation
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{
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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 ) );
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}
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}
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if ( transformString.compare( string, Qt::CaseInsensitive ) == 0 )
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{
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return statement.columnAsInt64( 8 );
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}
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}
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return -1;
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}
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void QgsCoordinateTransformPrivate::addNullGridShifts( QString &srcProjString, QString &destProjString,
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int sourceDatumTransform, int destinationDatumTransform ) const
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{

‎src/core/qgscoordinatetransform_p.h

Lines changed: 14 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -135,7 +135,20 @@ class QgsCoordinateTransformPrivate : public QSharedData
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QReadWriteLock mProjLock;
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QMap < uintptr_t, QPair< projPJ, projPJ > > mProjProjections;
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138-
static QString datumTransformString( int datumTransform );
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/**
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* Returns the proj transform string corresponding to a
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* datum transform ID.
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* \see transformIdFromString()
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*/
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static QString datumTransformString( int transformId );
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/**
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* Attempts to match a proj datum transform string to a datum ID.
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* Returns -1 if datum ID was not found.
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* \see datumTransformString()
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* \since QGIS 3.0
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*/
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static int transformIdFromString( const QString &string );
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private:
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‎tests/src/python/test_qgscoordinatetransform.py

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Original file line numberDiff line numberDiff line change
@@ -218,6 +218,19 @@ def testTransformInfo(self):
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self.assertIn('EPSG:4326', [QgsCoordinateTransform.datumTransformInfo(t.destinationTransformId).destinationCrsAuthId for t in
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transforms])
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def testStringToTransformId(self):
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"""
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Test converting proj strings to corresponding datum IDs
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"""
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self.assertEqual(QgsCoordinateTransform.projStringToDatumTransformId(''), -1)
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self.assertEqual(QgsCoordinateTransform.projStringToDatumTransformId('not'), -1)
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test_string = '+towgs84=-403,684,41'
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id = QgsCoordinateTransform.projStringToDatumTransformId(test_string)
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self.assertNotEqual(id, -1)
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string = QgsCoordinateTransform.datumTransformToProj(id)
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self.assertEqual(string, test_string)
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self.assertEqual(QgsCoordinateTransform.projStringToDatumTransformId(test_string.upper()), id)
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if __name__ == '__main__':
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unittest.main()

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