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Better duplicate node detection/removal handling

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nyalldawson committed Oct 16, 2020
1 parent 5f67531 commit 41a30ac2e48cb343358b7ad902dbe6f285373672
@@ -421,9 +421,9 @@ segment in the line.
virtual bool removeDuplicateNodes( double epsilon = 4 * DBL_EPSILON, bool useZValues = false );


bool hasDuplicateNodes( double epsilon = 4 * DBL_EPSILON, bool useZValues = false ) const;
QVector< QgsVertexId > collectDuplicateNodes( double epsilon = 4 * DBL_EPSILON, bool useZValues = false ) const;
%Docstring
Returns ``True`` if the linestring contains duplicate nodes within the specified tolerance.
Returns a list of any duplicate nodes contained in the geometry, within the specified tolerance.

If ``useZValues`` is ``True`` then z values will also be considered when testing for duplicates.

@@ -363,10 +363,11 @@ bool QgsLineString::removeDuplicateNodes( double epsilon, bool useZValues )
return result;
}

bool QgsLineString::hasDuplicateNodes( double epsilon, bool useZValues ) const
QVector< QgsVertexId > QgsLineString::collectDuplicateNodes( double epsilon, bool useZValues ) const
{
QVector< QgsVertexId > res;
if ( mX.count() <= 1 )
return false;
return res;

const double *x = mX.constData();
const double *y = mY.constData();
@@ -377,6 +378,8 @@ bool QgsLineString::hasDuplicateNodes( double epsilon, bool useZValues ) const
double prevX = *x++;
double prevY = *y++;
double prevZ = z ? *z++ : 0;

QgsVertexId id;
for ( int i = 1; i < mX.count(); ++i )
{
double currentX = *x++;
@@ -386,7 +389,8 @@ bool QgsLineString::hasDuplicateNodes( double epsilon, bool useZValues ) const
qgsDoubleNear( currentY, prevY, epsilon ) &&
( !useZ || qgsDoubleNear( currentZ, prevZ, epsilon ) ) )
{
return true;
id.vertex = i;
res << id;
}
else
{
@@ -395,7 +399,7 @@ bool QgsLineString::hasDuplicateNodes( double epsilon, bool useZValues ) const
prevZ = currentZ;
}
}
return false;
return res;
}

QPolygonF QgsLineString::asQPolygonF() const
@@ -590,13 +590,13 @@ class CORE_EXPORT QgsLineString: public QgsCurve
bool removeDuplicateNodes( double epsilon = 4 * std::numeric_limits<double>::epsilon(), bool useZValues = false ) override;

/**
* Returns TRUE if the linestring contains duplicate nodes within the specified tolerance.
* Returns a list of any duplicate nodes contained in the geometry, within the specified tolerance.
*
* If \a useZValues is TRUE then z values will also be considered when testing for duplicates.
*
* \since QGIS 3.16
*/
bool hasDuplicateNodes( double epsilon = 4 * std::numeric_limits<double>::epsilon(), bool useZValues = false ) const;
QVector< QgsVertexId > collectDuplicateNodes( double epsilon = 4 * std::numeric_limits<double>::epsilon(), bool useZValues = false ) const;

QPolygonF asQPolygonF() const override;

@@ -116,42 +116,48 @@ void QgsGeometryValidator::validatePolyline( int i, const QgsLineString *line, b
return;
}

int j = 0;
std::unique_ptr< QgsLineString > noDupes;

// QgsLineString::hasDuplicateNodes() is much more efficient then the duplicate
// point detection/removal code below, so assume the
// most likely situation that a linestring DOESN'T have duplicate nodes
// and defer the expensive duplicate point emission/removal to only if
// we really need to do it
if ( line->hasDuplicateNodes( 1E-8 ) )
// test for duplicate nodes, and if we find any flag errors and then remove them so that the subsequent
// tests work OK.
const QVector< QgsVertexId > duplicateNodes = line->collectDuplicateNodes( 1E-8 );
if ( !duplicateNodes.empty() )
{
noDupes.reset( line->clone() );
while ( j < noDupes->numPoints() - 1 )
for ( int j = duplicateNodes.size() - 1; j >= 0; j-- )
{
int n = 0;
QgsPointXY dupeLocation;
while ( j < noDupes->numPoints() - 1 && qgsDoubleNear( noDupes->xAt( j ), noDupes->xAt( j + 1 ), 1E-8 ) && qgsDoubleNear( noDupes->yAt( j ), noDupes->yAt( j + 1 ), 1E-8 ) )
{
dupeLocation = QgsPointXY( noDupes->pointN( j ) );
noDupes->deleteVertex( QgsVertexId( -1, -1, j ) );
n++;
}
const QgsVertexId duplicateVertex = duplicateNodes.at( j );
const QgsPointXY duplicationLocation = noDupes->vertexAt( duplicateVertex );
noDupes->deleteVertex( duplicateVertex );
int n = 1;

if ( n > 0 )
// count how many other points exist at this location too
for ( int k = j - 1; k >= 0; k-- )
{
QString msg = QObject::tr( "line %1 contains %n duplicate node(s) at %2", "number of duplicate nodes", n ).arg( i ).arg( j );
QgsDebugMsgLevel( msg, 2 );
emit errorFound( QgsGeometry::Error( msg, dupeLocation ) );
mErrorCount++;
const QgsVertexId prevDupe = duplicateNodes.at( k );
const QgsPoint prevPoint = noDupes->vertexAt( prevDupe );
if ( qgsDoubleNear( duplicationLocation.x(), prevPoint.x(), 1E-8 ) && qgsDoubleNear( duplicationLocation.y(), prevPoint.y(), 1E-8 ) )
{
noDupes->deleteVertex( prevDupe );
n++;
}
else
{
break;
}
}

j++;
j -= n - 1;

QString msg = QObject::tr( "line %1 contains %n duplicate node(s) starting at vertex %2", "number of duplicate nodes", n + 1 ).arg( i + 1 ).arg( duplicateVertex.vertex - n + 1 );
QgsDebugMsgLevel( msg, 2 );
emit errorFound( QgsGeometry::Error( msg, duplicationLocation ) );
mErrorCount++;
}
line = noDupes.get();
}

for ( j = 0; !mStop && j < line->numPoints() - 3; j++ )
for ( int j = 0; !mStop && j < line->numPoints() - 3; j++ )
{
const double xAtJ = line->xAt( j );
const double yAtJ = line->yAt( j );
@@ -12,13 +12,19 @@

from qgis.core import (
QgsGeometry,
QgsGeometryValidator
QgsGeometryValidator,
QgsPointXY
)

from qgis.testing import (
unittest
unittest,
start_app
)

from qgis.PyQt.QtTest import QSignalSpy

app = start_app()


class TestQgsGeometryValidator(unittest.TestCase):

@@ -60,6 +66,23 @@ def testIssue15660(self):
# make sure validating this geometry doesn't crash QGIS
QgsGeometryValidator.validateGeometry(g)

def test_linestring_duplicate_nodes(self):
g = QgsGeometry.fromWkt("LineString (1 1, 1 1, 1 1, 1 2, 1 3, 1 3, 1 3, 1 4, 1 5, 1 6, 1 6)")

validator = QgsGeometryValidator(g)
spy = QSignalSpy(validator.errorFound)
validator.run()

self.assertEqual(len(spy), 3)
self.assertEqual(spy[0][0].where(), QgsPointXY(1, 6))
self.assertEqual(spy[0][0].what(), 'line 1 contains 2 duplicate node(s) starting at vertex 10')

self.assertEqual(spy[1][0].where(), QgsPointXY(1, 3))
self.assertEqual(spy[1][0].what(), 'line 1 contains 3 duplicate node(s) starting at vertex 5')

self.assertEqual(spy[2][0].where(), QgsPointXY(1, 1))
self.assertEqual(spy[2][0].what(), 'line 1 contains 3 duplicate node(s) starting at vertex 1')


if __name__ == '__main__':
unittest.main()

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