Merge pull request #6525 from nyalldawson/segmentize

[FEATURE][processing] Add "segmentize" algorithms

python/core/geometry/qgsgeometry.sip.in

@@ -1423,10 +1423,13 @@ An empty geometry will be returned in the case of errors.
 .. versionadded:: 3.0
 %End
 
-    void convertToStraightSegment();
+    void convertToStraightSegment( double tolerance = M_PI / 180., QgsAbstractGeometry::SegmentationToleranceType toleranceType = QgsAbstractGeometry::MaximumAngle );
 %Docstring
 Converts the geometry to straight line segments, if it is a curved geometry type.
 
+:param tolerance: segmentation tolerance
+:param toleranceType: maximum segmentation angle or maximum difference between approximation and curve
+
 .. versionadded:: 2.10
 
 .. seealso:: :py:func:`requiresConversionToStraightSegments`

python/plugins/processing/tests/testdata/expected/segmentize_by_angle.gml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ogr:FeatureCollection
+     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+     xsi:schemaLocation="http://ogr.maptools.org/ segmentize_by_angle.xsd"
+     xmlns:ogr="http://ogr.maptools.org/"
+     xmlns:gml="http://www.opengis.net/gml">
+  <gml:boundedBy>
+    <gml:Box>
+      <gml:coord><gml:X>-0.9875563570784498</gml:X><gml:Y>-3.019161406672679</gml:Y></gml:coord>
+      <gml:coord><gml:X>9.807504202322207</gml:X><gml:Y>4.303079673657821</gml:Y></gml:coord>
+    </gml:Box>
+  </gml:boundedBy>
+
+  <gml:featureMember>
+    <ogr:segmentize_by_angle fid="1">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>-0.98755635707845,-0.974075743913436 -0.696095751086827,0.344850591369106 -0.005888714481605,1.50594068665349 1.01349196457716,2.39215679681429 2.25929283346249,2.91416844211677 3.60593731102726,3.0193569100738 4.91768379222303,2.6971192154796 6.06230838593327,1.97993688007214</gml:coordinates></gml:LineString></ogr:geometryProperty>
+      <ogr:id>1</ogr:id>
+    </ogr:segmentize_by_angle>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:segmentize_by_angle fid="2">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>6.91442741208296,-3.01916140667268 6.32475035835957,-2.4284524156428 5.95800750896124,-1.67868190262791 5.8536814658075,-0.850568253126039 6.0230037052269,-0.033264075350454 6.44774542579607,0.68524174270488 7.08218001471432,1.22759669304234 7.85800585857777,1.53541222183353 8.69169952127193,1.57554969254374 9.49350766456267,1.34368800721371 9.74057664392659,1.88754171095694 9.80750420232221,2.48112458938787 9.68773977279365,3.06633943289311 9.39300535646221,3.58590805730082 8.95214822603083,3.98897743369522 8.40831748509891,4.23609695307115 7.81474082890195,4.30307967365782 7.22951485804922,4.18336962947338 6.70991884580703,3.88868349864743</gml:coordinates></gml:LineString></ogr:geometryProperty>
+      <ogr:id>2</ogr:id>
+    </ogr:segmentize_by_angle>
+  </gml:featureMember>
+</ogr:FeatureCollection>

python/plugins/processing/tests/testdata/expected/segmentize_by_angle.xsd

@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<xs:schema targetNamespace="http://ogr.maptools.org/" xmlns:ogr="http://ogr.maptools.org/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:gml="http://www.opengis.net/gml" elementFormDefault="qualified" version="1.0">
+<xs:import namespace="http://www.opengis.net/gml" schemaLocation="http://schemas.opengis.net/gml/2.1.2/feature.xsd"/>
+<xs:element name="FeatureCollection" type="ogr:FeatureCollectionType" substitutionGroup="gml:_FeatureCollection"/>
+<xs:complexType name="FeatureCollectionType">
+  <xs:complexContent>
+    <xs:extension base="gml:AbstractFeatureCollectionType">
+      <xs:attribute name="lockId" type="xs:string" use="optional"/>
+      <xs:attribute name="scope" type="xs:string" use="optional"/>
+    </xs:extension>
+  </xs:complexContent>
+</xs:complexType>
+<xs:element name="segmentize_by_angle" type="ogr:segmentize_by_angle_Type" substitutionGroup="gml:_Feature"/>
+<xs:complexType name="segmentize_by_angle_Type">
+  <xs:complexContent>
+    <xs:extension base="gml:AbstractFeatureType">
+      <xs:sequence>
+        <xs:element name="geometryProperty" type="gml:LineStringPropertyType" nillable="true" minOccurs="0" maxOccurs="1"/>
+        <xs:element name="id" nillable="true" minOccurs="0" maxOccurs="1">
+          <xs:simpleType>
+            <xs:restriction base="xs:integer">
+              <xs:totalDigits value="10"/>
+            </xs:restriction>
+          </xs:simpleType>
+        </xs:element>
+      </xs:sequence>
+    </xs:extension>
+  </xs:complexContent>
+</xs:complexType>
+</xs:schema>

python/plugins/processing/tests/testdata/expected/segmentize_by_distance.gml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ogr:FeatureCollection
+     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+     xsi:schemaLocation="http://ogr.maptools.org/ segmentize_by_distance.xsd"
+     xmlns:ogr="http://ogr.maptools.org/"
+     xmlns:gml="http://www.opengis.net/gml">
+  <gml:boundedBy>
+    <gml:Box>
+      <gml:coord><gml:X>-0.9875563570784498</gml:X><gml:Y>-3.019161406672679</gml:Y></gml:coord>
+      <gml:coord><gml:X>9.794917283570138</gml:X><gml:Y>4.303894025825194</gml:Y></gml:coord>
+    </gml:Box>
+  </gml:boundedBy>
+
+  <gml:featureMember>
+    <ogr:segmentize_by_distance fid="1">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>-0.98755635707845,-0.974075743913436 -0.212652411335007,1.23725667259743 1.61554353037206,2.70291924637298 3.94247675733233,2.9783261066885 6.06230838593327,1.97993688007214</gml:coordinates></gml:LineString></ogr:geometryProperty>
+      <ogr:id>1</ogr:id>
+    </ogr:segmentize_by_distance>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:segmentize_by_distance fid="2">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>6.91442741208296,-3.01916140667268 5.90638239076692,-1.47558750786245 6.20570477434748,0.34352800709968 7.65518199185988,1.48273428429481 9.49350766456267,1.34368800721371 9.79491728357014,2.63050854973142 9.18843697294715,3.80478981923308 7.96465191909257,4.30389402582519 6.70991884580703,3.88868349864743</gml:coordinates></gml:LineString></ogr:geometryProperty>
+      <ogr:id>2</ogr:id>
+    </ogr:segmentize_by_distance>
+  </gml:featureMember>
+</ogr:FeatureCollection>

python/plugins/processing/tests/testdata/expected/segmentize_by_distance.xsd

@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<xs:schema targetNamespace="http://ogr.maptools.org/" xmlns:ogr="http://ogr.maptools.org/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:gml="http://www.opengis.net/gml" elementFormDefault="qualified" version="1.0">
+<xs:import namespace="http://www.opengis.net/gml" schemaLocation="http://schemas.opengis.net/gml/2.1.2/feature.xsd"/>
+<xs:element name="FeatureCollection" type="ogr:FeatureCollectionType" substitutionGroup="gml:_FeatureCollection"/>
+<xs:complexType name="FeatureCollectionType">
+  <xs:complexContent>
+    <xs:extension base="gml:AbstractFeatureCollectionType">
+      <xs:attribute name="lockId" type="xs:string" use="optional"/>
+      <xs:attribute name="scope" type="xs:string" use="optional"/>
+    </xs:extension>
+  </xs:complexContent>
+</xs:complexType>
+<xs:element name="segmentize_by_distance" type="ogr:segmentize_by_distance_Type" substitutionGroup="gml:_Feature"/>
+<xs:complexType name="segmentize_by_distance_Type">
+  <xs:complexContent>
+    <xs:extension base="gml:AbstractFeatureType">
+      <xs:sequence>
+        <xs:element name="geometryProperty" type="gml:LineStringPropertyType" nillable="true" minOccurs="0" maxOccurs="1"/>
+        <xs:element name="id" nillable="true" minOccurs="0" maxOccurs="1">
+          <xs:simpleType>
+            <xs:restriction base="xs:integer">
+              <xs:totalDigits value="10"/>
+            </xs:restriction>
+          </xs:simpleType>
+        </xs:element>
+      </xs:sequence>
+    </xs:extension>
+  </xs:complexContent>
+</xs:complexType>
+</xs:schema>

python/plugins/processing/tests/testdata/qgis_algorithm_tests.yaml

@@ -4818,3 +4818,27 @@ tests:
       OUTPUT:
         name: expected/multiring_buffer.gml
         type: vector
+
+  - algorithm: native:segmentizebymaxangle
+    name: Segmentize by angle
+    params:
+      ANGLE: 20.0
+      INPUT:
+        name: custom/circular_strings.gpkg|layername=circular_strings
+        type: vector
+    results:
+      OUTPUT:
+        name: expected/segmentize_by_angle.gml
+        type: vector
+
+  - algorithm: native:segmentizebymaxdistance
+    name: Segmentize by distance
+    params:
+      DISTANCE: 0.2
+      INPUT:
+        name: custom/circular_strings.gpkg|layername=circular_strings
+        type: vector
+    results:
+      OUTPUT:
+        name: expected/segmentize_by_distance.gml
+        type: vector

src/analysis/CMakeLists.txt

@@ -59,6 +59,7 @@ SET(QGIS_ANALYSIS_SRCS
   processing/qgsalgorithmremovenullgeometry.cpp
   processing/qgsalgorithmrenamelayer.cpp
   processing/qgsalgorithmsaveselectedfeatures.cpp
+  processing/qgsalgorithmsegmentize.cpp
   processing/qgsalgorithmsimplify.cpp
   processing/qgsalgorithmsmooth.cpp
   processing/qgsalgorithmsnaptogrid.cpp

src/analysis/processing/qgsalgorithmsegmentize.cpp

@@ -0,0 +1,197 @@
+/***************************************************************************
+                         qgsalgorithmsegmentize.cpp
+                         ---------------------
+    begin                : March 2018
+    copyright            : (C) 2018 by 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 "qgsalgorithmsegmentize.h"
+
+///@cond PRIVATE
+
+QString QgsSegmentizeByMaximumDistanceAlgorithm::name() const
+{
+  return QStringLiteral( "segmentizebymaxdistance" );
+}
+
+QString QgsSegmentizeByMaximumDistanceAlgorithm::displayName() const
+{
+  return QObject::tr( "Segmentize by maximum distance" );
+}
+
+QStringList QgsSegmentizeByMaximumDistanceAlgorithm::tags() const
+{
+  return QObject::tr( "straighten,linearize,densify,curves,curved,circular" ).split( ',' );
+}
+
+QString QgsSegmentizeByMaximumDistanceAlgorithm::group() const
+{
+  return QObject::tr( "Vector geometry" );
+}
+
+QString QgsSegmentizeByMaximumDistanceAlgorithm::groupId() const
+{
+  return QStringLiteral( "vectorgeometry" );
+}
+
+QString QgsSegmentizeByMaximumDistanceAlgorithm::outputName() const
+{
+  return QObject::tr( "Segmentized" );
+}
+
+QString QgsSegmentizeByMaximumDistanceAlgorithm::shortHelpString() const
+{
+  return QObject::tr( "This algorithm segmentizes a geometry by converting curved sections to linear sections.\n\n"
+                      "The segmentization is performed by specifying the maximum allowed offset distance between the original"
+                      "curve and the segmentized representation.\n\n"
+                      "Non-curved geometries will be retained without change." );
+}
+
+QgsSegmentizeByMaximumDistanceAlgorithm *QgsSegmentizeByMaximumDistanceAlgorithm::createInstance() const
+{
+  return new QgsSegmentizeByMaximumDistanceAlgorithm();
+}
+
+QList<int> QgsSegmentizeByMaximumDistanceAlgorithm::inputLayerTypes() const
+{
+  return QList<int>() << QgsProcessing::TypeVectorLine << QgsProcessing::TypeVectorPolygon;
+}
+
+void QgsSegmentizeByMaximumDistanceAlgorithm::initParameters( const QVariantMap & )
+{
+  std::unique_ptr< QgsProcessingParameterNumber > tolerance = qgis::make_unique< QgsProcessingParameterNumber >( QStringLiteral( "DISTANCE" ),
+      QObject::tr( "Maximum offset distance" ), QgsProcessingParameterNumber::Double,
+      1.0, false, 0, 10000000.0 );
+  tolerance->setIsDynamic( true );
+  tolerance->setDynamicPropertyDefinition( QgsPropertyDefinition( QStringLiteral( "DISTANCE" ), QObject::tr( "Maximum offset distance" ), QgsPropertyDefinition::DoublePositive ) );
+  tolerance->setDynamicLayerParameterName( QStringLiteral( "INPUT" ) );
+  addParameter( tolerance.release() );
+}
+
+bool QgsSegmentizeByMaximumDistanceAlgorithm::prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback * )
+{
+  mTolerance = parameterAsDouble( parameters, QStringLiteral( "DISTANCE" ), context );
+  mDynamicTolerance = QgsProcessingParameters::isDynamic( parameters, QStringLiteral( "DISTANCE" ) );
+  if ( mDynamicTolerance )
+    mToleranceProperty = parameters.value( QStringLiteral( "DISTANCE" ) ).value< QgsProperty >();
+
+  return true;
+}
+
+QgsFeatureList QgsSegmentizeByMaximumDistanceAlgorithm::processFeature( const QgsFeature &feature, QgsProcessingContext &context, QgsProcessingFeedback * )
+{
+  QgsFeature f = feature;
+  if ( f.hasGeometry() )
+  {
+    QgsGeometry geometry = f.geometry();
+    double tolerance = mTolerance;
+    if ( mDynamicTolerance )
+      tolerance = mToleranceProperty.valueAsDouble( context.expressionContext(), tolerance );
+    geometry.convertToStraightSegment( tolerance, QgsAbstractGeometry::MaximumDifference );
+    f.setGeometry( geometry );
+  }
+  return QgsFeatureList() << f;
+}
+
+
+
+
+
+QString QgsSegmentizeByMaximumAngleAlgorithm::name() const
+{
+  return QStringLiteral( "segmentizebymaxangle" );
+}
+
+QString QgsSegmentizeByMaximumAngleAlgorithm::displayName() const
+{
+  return QObject::tr( "Segmentize by maximum angle" );
+}
+
+QStringList QgsSegmentizeByMaximumAngleAlgorithm::tags() const
+{
+  return QObject::tr( "straighten,linearize,densify,curves,curved,circular,angle" ).split( ',' );
+}
+
+QString QgsSegmentizeByMaximumAngleAlgorithm::group() const
+{
+  return QObject::tr( "Vector geometry" );
+}
+
+QString QgsSegmentizeByMaximumAngleAlgorithm::groupId() const
+{
+  return QStringLiteral( "vectorgeometry" );
+}
+
+QString QgsSegmentizeByMaximumAngleAlgorithm::outputName() const
+{
+  return QObject::tr( "Segmentized" );
+}
+
+QString QgsSegmentizeByMaximumAngleAlgorithm::shortHelpString() const
+{
+  return QObject::tr( "This algorithm segmentizes a geometry by converting curved sections to linear sections.\n\n"
+                      "The segmentization is performed by specifying the maximum allowed radius angle between vertices"
+                      "on the straightened geometry (e.g the angle of the arc created from the original arc center to consective"
+                      "output vertices on the linearized geometry).\n\n"
+                      "Non-curved geometries will be retained without change." );
+}
+
+QgsSegmentizeByMaximumAngleAlgorithm *QgsSegmentizeByMaximumAngleAlgorithm::createInstance() const
+{
+  return new QgsSegmentizeByMaximumAngleAlgorithm();
+}
+
+QList<int> QgsSegmentizeByMaximumAngleAlgorithm::inputLayerTypes() const
+{
+  return QList<int>() << QgsProcessing::TypeVectorLine << QgsProcessing::TypeVectorPolygon;
+}
+
+void QgsSegmentizeByMaximumAngleAlgorithm::initParameters( const QVariantMap & )
+{
+  std::unique_ptr< QgsProcessingParameterNumber > tolerance = qgis::make_unique< QgsProcessingParameterNumber >( QStringLiteral( "ANGLE" ),
+      QObject::tr( "Maximum angle between vertices (degrees)" ), QgsProcessingParameterNumber::Double,
+      5.0, false, 0, 360.0 );
+  tolerance->setIsDynamic( true );
+  tolerance->setDynamicPropertyDefinition( QgsPropertyDefinition( QStringLiteral( "ANGLE" ), QObject::tr( "Maximum angle between vertices (degrees)" ), QgsPropertyDefinition::DoublePositive ) );
+  tolerance->setDynamicLayerParameterName( QStringLiteral( "INPUT" ) );
+  addParameter( tolerance.release() );
+}
+
+bool QgsSegmentizeByMaximumAngleAlgorithm::prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback * )
+{
+  mTolerance = parameterAsDouble( parameters, QStringLiteral( "ANGLE" ), context );
+  mDynamicTolerance = QgsProcessingParameters::isDynamic( parameters, QStringLiteral( "ANGLE" ) );
+  if ( mDynamicTolerance )
+    mToleranceProperty = parameters.value( QStringLiteral( "ANGLE" ) ).value< QgsProperty >();
+
+  return true;
+}
+
+QgsFeatureList QgsSegmentizeByMaximumAngleAlgorithm::processFeature( const QgsFeature &feature, QgsProcessingContext &context, QgsProcessingFeedback * )
+{
+  QgsFeature f = feature;
+  if ( f.hasGeometry() )
+  {
+    QgsGeometry geometry = f.geometry();
+    double tolerance = mTolerance;
+    if ( mDynamicTolerance )
+      tolerance = mToleranceProperty.valueAsDouble( context.expressionContext(), tolerance );
+    geometry.convertToStraightSegment( M_PI * tolerance / 180.0, QgsAbstractGeometry::MaximumAngle );
+    f.setGeometry( geometry );
+  }
+  return QgsFeatureList() << f;
+}
+
+///@endcond
+
+