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[FEATURE][processing] Extract nodes algorithm now saves node
index, distance along line and angle at node Also correctly handles null geometries
1 parent 986b531 commit 9fa4e77

11 files changed

+1088
-15
lines changed

‎python/plugins/processing/algs/help/qgis.yaml

+2
Original file line numberDiff line numberDiff line change
@@ -166,6 +166,8 @@ qgis:extractbylocation: >
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qgis:extractnodes: >
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This algorithm takes a line or polygon layer and generates a point layer with points representing the nodes in the input lines or polygons. The attributes associated to each point are the same ones associated to the line or polygon that the point belongs to.
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Additional fields are added to the nodes indicating the node index (beginning at 0), distance along original geometry and bisector angle of node for original geometry.
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qgis:fieldcalculator: >
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This algorithm computes a new vector layer with the same features of the input layer, but with an additional attribute. The values of this new attribute are computed from each feature using a mathematical formula, based on te properties and attributes of the feature.
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‎python/plugins/processing/algs/qgis/ExtractNodes.py

+26-15
Original file line numberDiff line numberDiff line change
@@ -26,10 +26,12 @@
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__revision__ = '$Format:%H$'
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import os
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import math
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from qgis.PyQt.QtGui import QIcon
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from qgis.PyQt.QtCore import QVariant
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from qgis.core import Qgis, QgsFeature, QgsGeometry, QgsWkbTypes
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from qgis.core import QgsFeature, QgsGeometry, QgsWkbTypes, QgsField
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from processing.core.GeoAlgorithm import GeoAlgorithm
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from processing.core.parameters import ParameterVector
@@ -61,25 +63,34 @@ def processAlgorithm(self, progress):
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layer = dataobjects.getObjectFromUri(
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self.getParameterValue(self.INPUT))
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writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(
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layer.fields().toList(), QgsWkbTypes.Point, layer.crs())
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fields = layer.fields()
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fields.append(QgsField('node_index', QVariant.Int))
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fields.append(QgsField('distance', QVariant.Double))
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fields.append(QgsField('angle', QVariant.Double))
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outFeat = QgsFeature()
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inGeom = QgsGeometry()
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outGeom = QgsGeometry()
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writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(
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fields, QgsWkbTypes.Point, layer.crs())
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features = vector.features(layer)
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total = 100.0 / len(features)
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for current, f in enumerate(features):
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inGeom = f.geometry()
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attrs = f.attributes()
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points = vector.extractPoints(inGeom)
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outFeat.setAttributes(attrs)
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for i in points:
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outFeat.setGeometry(outGeom.fromPoint(i))
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writer.addFeature(outFeat)
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input_geometry = f.geometry()
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if not input_geometry:
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writer.addFeature(f)
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else:
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points = vector.extractPoints(input_geometry)
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for i, point in enumerate(points):
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distance = input_geometry.distanceToVertex(i)
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angle = math.degrees(input_geometry.angleAtVertex(i))
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attrs = f.attributes()
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attrs.append(i)
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attrs.append(distance)
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attrs.append(angle)
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output_feature = QgsFeature()
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output_feature.setAttributes(attrs)
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output_feature.setGeometry(QgsGeometry.fromPoint(point))
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writer.addFeature(output_feature)
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progress.setPercentage(int(current * total))
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‎python/plugins/processing/tests/testdata/expected/extract_nodes_lines.gfs

+25
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,25 @@
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<GMLFeatureClassList>
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<GMLFeatureClass>
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<Name>extract_nodes_lines</Name>
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<ElementPath>extract_nodes_lines</ElementPath>
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<GeometryType>1</GeometryType>
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<SRSName>EPSG:4326</SRSName>
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<DatasetSpecificInfo>
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<FeatureCount>17</FeatureCount>
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<ExtentXMin>-1.00000</ExtentXMin>
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<ExtentXMax>11.00000</ExtentXMax>
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<ExtentYMin>-3.00000</ExtentYMin>
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<ExtentYMax>5.00000</ExtentYMax>
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</DatasetSpecificInfo>
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<PropertyDefn>
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<Name>distance</Name>
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<ElementPath>distance</ElementPath>
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<Type>Real</Type>
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</PropertyDefn>
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<PropertyDefn>
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<Name>angle</Name>
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<ElementPath>angle</ElementPath>
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<Type>Real</Type>
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</PropertyDefn>
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</GMLFeatureClass>
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</GMLFeatureClassList>

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

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@@ -0,0 +1,146 @@
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<?xml version="1.0" encoding="utf-8" ?>
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<ogr:FeatureCollection
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation=""
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xmlns:ogr="http://ogr.maptools.org/"
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xmlns:gml="http://www.opengis.net/gml">
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<gml:boundedBy>
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<gml:Box>
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<gml:coord><gml:X>-1</gml:X><gml:Y>-3</gml:Y></gml:coord>
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<gml:coord><gml:X>11</gml:X><gml:Y>5</gml:Y></gml:coord>
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</gml:Box>
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</gml:boundedBy>
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<gml:featureMember>
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<ogr:extract_nodes_lines fid="lines.0">
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<ogr:geometryProperty><gml:Point srsName="EPSG:4326"><gml:coordinates>6,2</gml:coordinates></gml:Point></ogr:geometryProperty>
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<ogr:node_index>0</ogr:node_index>
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<ogr:distance>0</ogr:distance>
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<ogr:angle>90</ogr:angle>
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</ogr:extract_nodes_lines>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:extract_nodes_lines fid="lines.0">
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<ogr:geometryProperty><gml:Point srsName="EPSG:4326"><gml:coordinates>9,2</gml:coordinates></gml:Point></ogr:geometryProperty>
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<ogr:node_index>1</ogr:node_index>
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<ogr:distance>3</ogr:distance>
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<ogr:angle>45</ogr:angle>
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</ogr:extract_nodes_lines>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:extract_nodes_lines fid="lines.0">
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<ogr:geometryProperty><gml:Point srsName="EPSG:4326"><gml:coordinates>9,3</gml:coordinates></gml:Point></ogr:geometryProperty>
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<ogr:node_index>2</ogr:node_index>
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<ogr:distance>4</ogr:distance>
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<ogr:angle>22.5</ogr:angle>
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</ogr:extract_nodes_lines>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:extract_nodes_lines fid="lines.0">
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<ogr:geometryProperty><gml:Point srsName="EPSG:4326"><gml:coordinates>11,5</gml:coordinates></gml:Point></ogr:geometryProperty>
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<ogr:node_index>3</ogr:node_index>
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<ogr:distance>6.82842712474619</ogr:distance>
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<ogr:angle>45</ogr:angle>
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</ogr:extract_nodes_lines>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:extract_nodes_lines fid="lines.1">
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<ogr:geometryProperty><gml:Point srsName="EPSG:4326"><gml:coordinates>-1,-1</gml:coordinates></gml:Point></ogr:geometryProperty>
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<ogr:node_index>0</ogr:node_index>
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<ogr:distance>0</ogr:distance>
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<ogr:angle>90</ogr:angle>
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</ogr:extract_nodes_lines>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:extract_nodes_lines fid="lines.1">
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<ogr:geometryProperty><gml:Point srsName="EPSG:4326"><gml:coordinates>1,-1</gml:coordinates></gml:Point></ogr:geometryProperty>
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<ogr:node_index>1</ogr:node_index>
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<ogr:distance>2</ogr:distance>
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<ogr:angle>90</ogr:angle>
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</ogr:extract_nodes_lines>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:extract_nodes_lines fid="lines.2">
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<ogr:geometryProperty><gml:Point srsName="EPSG:4326"><gml:coordinates>2,0</gml:coordinates></gml:Point></ogr:geometryProperty>
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<ogr:node_index>0</ogr:node_index>
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<ogr:distance>0</ogr:distance>
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<ogr:angle>0</ogr:angle>
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</ogr:extract_nodes_lines>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:extract_nodes_lines fid="lines.2">
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<ogr:geometryProperty><gml:Point srsName="EPSG:4326"><gml:coordinates>2,2</gml:coordinates></gml:Point></ogr:geometryProperty>
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<ogr:node_index>1</ogr:node_index>
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<ogr:distance>2</ogr:distance>
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<ogr:angle>45</ogr:angle>
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</ogr:extract_nodes_lines>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:extract_nodes_lines fid="lines.2">
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<ogr:geometryProperty><gml:Point srsName="EPSG:4326"><gml:coordinates>3,2</gml:coordinates></gml:Point></ogr:geometryProperty>
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<ogr:node_index>2</ogr:node_index>
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<ogr:distance>3</ogr:distance>
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<ogr:angle>45</ogr:angle>
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</ogr:extract_nodes_lines>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:extract_nodes_lines fid="lines.2">
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<ogr:geometryProperty><gml:Point srsName="EPSG:4326"><gml:coordinates>3,3</gml:coordinates></gml:Point></ogr:geometryProperty>
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<ogr:node_index>3</ogr:node_index>
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<ogr:distance>4</ogr:distance>
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<ogr:angle>0</ogr:angle>
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</ogr:extract_nodes_lines>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:extract_nodes_lines fid="lines.3">
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<ogr:geometryProperty><gml:Point srsName="EPSG:4326"><gml:coordinates>3,1</gml:coordinates></gml:Point></ogr:geometryProperty>
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<ogr:node_index>0</ogr:node_index>
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<ogr:distance>0</ogr:distance>
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<ogr:angle>90</ogr:angle>
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</ogr:extract_nodes_lines>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:extract_nodes_lines fid="lines.3">
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<ogr:geometryProperty><gml:Point srsName="EPSG:4326"><gml:coordinates>5,1</gml:coordinates></gml:Point></ogr:geometryProperty>
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<ogr:node_index>1</ogr:node_index>
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<ogr:distance>2</ogr:distance>
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<ogr:angle>90</ogr:angle>
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</ogr:extract_nodes_lines>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:extract_nodes_lines fid="lines.4">
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<ogr:geometryProperty><gml:Point srsName="EPSG:4326"><gml:coordinates>7,-3</gml:coordinates></gml:Point></ogr:geometryProperty>
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<ogr:node_index>0</ogr:node_index>
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<ogr:distance>0</ogr:distance>
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<ogr:angle>90</ogr:angle>
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</ogr:extract_nodes_lines>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:extract_nodes_lines fid="lines.4">
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<ogr:geometryProperty><gml:Point srsName="EPSG:4326"><gml:coordinates>10,-3</gml:coordinates></gml:Point></ogr:geometryProperty>
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<ogr:node_index>1</ogr:node_index>
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<ogr:distance>3</ogr:distance>
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<ogr:angle>90</ogr:angle>
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</ogr:extract_nodes_lines>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:extract_nodes_lines fid="lines.5">
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<ogr:geometryProperty><gml:Point srsName="EPSG:4326"><gml:coordinates>6,-3</gml:coordinates></gml:Point></ogr:geometryProperty>
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<ogr:node_index>0</ogr:node_index>
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<ogr:distance>0</ogr:distance>
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<ogr:angle>45</ogr:angle>
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</ogr:extract_nodes_lines>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:extract_nodes_lines fid="lines.5">
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<ogr:geometryProperty><gml:Point srsName="EPSG:4326"><gml:coordinates>10,1</gml:coordinates></gml:Point></ogr:geometryProperty>
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<ogr:node_index>1</ogr:node_index>
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<ogr:distance>5.65685424949238</ogr:distance>
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<ogr:angle>45</ogr:angle>
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</ogr:extract_nodes_lines>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:extract_nodes_lines fid="lines.6">
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</ogr:extract_nodes_lines>
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</gml:featureMember>
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</ogr:FeatureCollection>

‎python/plugins/processing/tests/testdata/expected/extract_nodes_multilines.gfs

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<GMLFeatureClassList>
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<GMLFeatureClass>
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<Name>extract_nodes_multilines</Name>
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<ElementPath>extract_nodes_multilines</ElementPath>
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<GeometryType>1</GeometryType>
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<SRSName>EPSG:4326</SRSName>
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<DatasetSpecificInfo>
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<FeatureCount>15</FeatureCount>
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<ExtentXMin>-1.00000</ExtentXMin>
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<ExtentXMax>5.58042</ExtentXMax>
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<ExtentYMin>-1.00000</ExtentYMin>
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<ExtentYMax>4.11977</ExtentYMax>
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</DatasetSpecificInfo>
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<PropertyDefn>
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<Name>distance</Name>
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<ElementPath>distance</ElementPath>
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<Type>Real</Type>
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</PropertyDefn>
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<PropertyDefn>
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<Name>angle</Name>
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<ElementPath>angle</ElementPath>
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<Type>Real</Type>
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</PropertyDefn>
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</GMLFeatureClass>
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</GMLFeatureClassList>

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