Improve split with lines

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

@@ -457,8 +457,8 @@ qgis:snappointstogrid: >
   This algorithm modifies the position of points in a vector layer, so they fall in the coordinates of a grid.
 
 
-qgis:splitlineswithlines: >
-  This algorithm split the lines in a line layer using the lines in another line layer to define the breaking points. Intersection between geometries in both layers are considered as split points.
+qgis:splitwithlines: >
+  This algorithm splits the lines or polygons in one layer using the lines in another layer to define the breaking points. Intersection between geometries in both layers are considered as split points.
 
 qgis:splitvectorlayer: >
   This algorithm takes a vector layer and an attribute and generates a set of vector layers in an outut folder. Each of the layers created in that folder contains all features from the input layer with the same value for the specified attribute.

python/plugins/processing/algs/qgis/QGISAlgorithmProvider.py

@@ -138,7 +138,7 @@
 from .SelectByExpression import SelectByExpression
 from .SelectByAttributeSum import SelectByAttributeSum
 from .HypsometricCurves import HypsometricCurves
-from .SplitLinesWithLines import SplitLinesWithLines
+from .SplitWithLines import SplitWithLines
 from .FieldsMapper import FieldsMapper
 from .Datasources2Vrt import Datasources2Vrt
 from .CheckValidity import CheckValidity
@@ -205,7 +205,7 @@ def __init__(self):
                         PostGISExecuteSQL(), ImportIntoPostGIS(),
                         SetVectorStyle(), SetRasterStyle(),
                         SelectByExpression(), HypsometricCurves(),
-                        SplitLinesWithLines(), CreateConstantRaster(),
+                        SplitWithLines(), CreateConstantRaster(),
                         FieldsMapper(), SelectByAttributeSum(), Datasources2Vrt(),
                         CheckValidity(), OrientedMinimumBoundingBox(), Smooth(),
                         ReverseLineDirection(), SpatialIndex(), DefineProjection(),

python/plugins/processing/algs/qgis/SplitWithLines.py

@@ -0,0 +1,173 @@
+# -*- coding: utf-8 -*-
+
+"""
+***************************************************************************
+    SplitWithLines.py
+    ---------------------
+    Date                 : November 2014
+    Revised              : September 2016
+    Copyright            : (C) 2014 by Bernhard Ströbl
+    Email                : bernhard dot stroebl at jena dot de
+***************************************************************************
+*                                                                         *
+*   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.                                   *
+*                                                                         *
+***************************************************************************
+"""
+
+__author__ = 'Bernhard Ströbl'
+__date__ = 'November 2014'
+__copyright__ = '(C) 2014, Bernhard Ströbl'
+
+# This will get replaced with a git SHA1 when you do a git archive
+
+__revision__ = '$Format:%H$'
+
+from qgis.core import Qgis, QgsFeatureRequest, QgsFeature, QgsGeometry, QgsWkbTypes
+from processing.core.GeoAlgorithm import GeoAlgorithm
+from processing.core.parameters import ParameterVector
+from processing.core.outputs import OutputVector
+from processing.core.ProcessingLog import ProcessingLog
+from processing.tools import dataobjects
+from processing.tools import vector
+
+
+class SplitWithLines(GeoAlgorithm):
+
+    INPUT_A = 'INPUT_A'
+    INPUT_B = 'INPUT_B'
+
+    OUTPUT = 'OUTPUT'
+
+    def defineCharacteristics(self):
+        self.name, self.i18n_name = self.trAlgorithm('Split with lines')
+        self.group, self.i18n_group = self.trAlgorithm('Vector overlay tools')
+        self.addParameter(ParameterVector(self.INPUT_A,
+                                          self.tr('Input layer, single geometries only'), [dataobjects.TYPE_VECTOR_POLYGON,
+                                          dataobjects.TYPE_VECTOR_LINE]))
+        self.addParameter(ParameterVector(self.INPUT_B,
+                                          self.tr('Split layer'), [dataobjects.TYPE_VECTOR_LINE]))
+
+        self.addOutput(OutputVector(self.OUTPUT, self.tr('Splitted')))
+
+    def processAlgorithm(self, progress):
+        layerA = dataobjects.getObjectFromUri(self.getParameterValue(self.INPUT_A))
+        splitLayer = dataobjects.getObjectFromUri(self.getParameterValue(self.INPUT_B))
+
+        sameLayer = self.getParameterValue(self.INPUT_A) == self.getParameterValue(self.INPUT_B)
+        fieldList = layerA.fields()
+
+        writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(fieldList,
+                                                                     layerA.wkbType(), layerA.crs())
+
+        spatialIndex = vector.spatialindex(splitLayer)
+        splitGeoms = {}
+
+        for aSplitFeature in vector.features(splitLayer):
+            splitGeoms[aSplitFeature.id()] = aSplitFeature.geometry()
+            # honor the case that user has selection on split layer and has setting "use selection"
+
+        outFeat = QgsFeature()
+        features = vector.features(layerA)
+        total = 100.0 / float(len(features))
+        allowedWkbTypes = [2, #WkbLineString
+            3, # WkbPolygon
+            -2147483646, #WkbLineString25D
+            -2147483645] # WkbPolygon25D
+        # MultiGeometries are not allowed because the result of a splitted ring is not clearly defined:
+        # 1) add both parts as new features
+        # 2) store one part as a new feature and the other one as ring of the multi geometry
+        # 2a) which part is which, seems arbitrary
+
+        multiGeoms = 0 # how many multi geometries were encountered
+
+        for current, inFeatA in enumerate(features):
+            inGeom = inFeatA.geometry()
+
+            if allowedWkbTypes.count(inGeom.wkbType()) == 0:
+                multiGeoms += 1
+            else:
+                attrsA = inFeatA.attributes()
+                outFeat.setAttributes(attrsA)
+                inGeoms = [inGeom]
+                lines = spatialIndex.intersects(inGeom.boundingBox())
+
+                if len(lines) > 0:  # has intersection of bounding boxes
+                    splittingLines = []
+
+                    for i in lines:
+                        try:
+                            splitGeom = splitGeoms[i]
+                        except:
+                            continue
+
+                        # check if trying to self-intersect
+                        if sameLayer:
+                            if inFeatA.id() == i:
+                                continue
+
+                        if inGeom.intersects(splitGeom):
+                            splittingLines.append(splitGeom)
+
+                    if len(splittingLines) > 0:
+                        for splitGeom in splittingLines:
+                            splitterPList = vector.extractPoints(splitGeom)
+                            outGeoms = []
+
+                            while len(inGeoms) > 0:
+                                inGeom = inGeoms.pop()
+                                inPoints = vector.extractPoints(inGeom)
+
+                                if inGeom.intersects(splitGeom):
+                                    try:
+                                        result, newGeometries, topoTestPoints = inGeom.splitGeometry(splitterPList, False)
+                                    except:
+                                        ProcessingLog.addToLog(ProcessingLog.LOG_WARNING,
+                                                               self.tr('Geometry exception while splitting'))
+                                        result = 1
+
+                                    # splitGeometry: If there are several intersections
+                                    # between geometry and splitLine, only the first one is considered.
+                                    if result == 0:  # split occurred
+
+                                        if inPoints == vector.extractPoints(inGeom):
+                                            # bug in splitGeometry: sometimes it returns 0 but
+                                            # the geometry is unchanged
+                                            outGeoms.append(inGeom)
+                                        else:
+                                            inGeoms.append(inGeom)
+
+                                            for aNewGeom in newGeometries:
+                                                inGeoms.append(aNewGeom)
+                                    else:
+                                        outGeoms.append(inGeom)
+                                else:
+                                    outGeoms.append(inGeom)
+
+                            inGeoms = outGeoms
+
+                for aGeom in inGeoms:
+                    passed = True
+
+                    if aGeom.wkbType == 2 or aGeom.wkbType == -2147483646:
+                        passed = len(aGeom.asPolyline()) > 2
+
+                        if not passed:
+                            passed = (len(aGeom.asPolyline()) == 2 and
+                                 aGeom.asPolyline()[0] != aGeom.asPolyline()[1])
+                            # sometimes splitting results in lines of zero length
+
+                    if passed:
+                        outFeat.setGeometry(aGeom)
+                        writer.addFeature(outFeat)
+
+            progress.setPercentage(int(current * total))
+
+        if multiGeoms > 0:
+            ProcessingLog.addToLog(ProcessingLog.LOG_INFO,
+                self.tr('Feature geometry error: %s input features ignored due to multi-geometry.') % str(multiGeoms))
+
+        del writer

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

@@ -0,0 +1,32 @@
+<GMLFeatureClassList>
+  <GMLFeatureClass>
+    <Name>polygons_split_with_lines</Name>
+    <ElementPath>polygons_split_with_lines</ElementPath>
+    <!--POLYGON-->
+    <GeometryType>3</GeometryType>
+    <SRSName>EPSG:4326</SRSName>
+    <DatasetSpecificInfo>
+      <FeatureCount>6</FeatureCount>
+      <ExtentXMin>-1.00000</ExtentXMin>
+      <ExtentXMax>10.00000</ExtentXMax>
+      <ExtentYMin>-3.00000</ExtentYMin>
+      <ExtentYMax>6.00000</ExtentYMax>
+    </DatasetSpecificInfo>
+    <PropertyDefn>
+      <Name>name</Name>
+      <ElementPath>name</ElementPath>
+      <Type>String</Type>
+      <Width>5</Width>
+    </PropertyDefn>
+    <PropertyDefn>
+      <Name>intval</Name>
+      <ElementPath>intval</ElementPath>
+      <Type>Integer</Type>
+    </PropertyDefn>
+    <PropertyDefn>
+      <Name>floatval</Name>
+      <ElementPath>floatval</ElementPath>
+      <Type>Real</Type>
+    </PropertyDefn>
+  </GMLFeatureClass>
+</GMLFeatureClassList>