Merge pull request #3379 from nyalldawson/processing

[FEATURE][processing] New algorithm for offsetting lines
qgis · Aug 11, 2016 · 8a31576 · 8a31576
2 parents 7ee55a7 + 82f4a82
commit 8a31576
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diff --git a/python/plugins/processing/algs/help/qgis.yaml b/python/plugins/processing/algs/help/qgis.yaml
@@ -257,6 +257,15 @@ qgis:numberofuniquevaluesinclasses: >
 
   The resulting layer contains the same features as the input layer, but with an additional attribute containing the count of unique values for that class.
 
+qgis:offsetline: >
+  This algorithm offsets lines by a specified distance. Positive distances will offset lines to the left, and negative distances will offset to the right of lines.
+
+  The segments parameter controls the number of line segments to use to approximate a quarter circle when creating rounded offsets.
+
+  The join style parameter specifies whether round, mitre or beveled joins should be used when offseting corners in a line.
+
+  The mitre limit parameter is only applicable for mitre join styles, and controls the maximum distance from the offset curve to use when creating a mitred join.
+
 qgis:orientedminimumboundingbox: >
   This algorithm takes a vector layer and generate a new one with the minimum rectangle that covers all the input features.
 

diff --git a/python/plugins/processing/algs/qgis/OffsetLine.py b/python/plugins/processing/algs/qgis/OffsetLine.py
@@ -0,0 +1,106 @@
+# -*- coding: utf-8 -*-
+
+"""
+***************************************************************************
+    OffsetLine.py
+    --------------
+    Date                 : July 2016
+    Copyright            : (C) 2016 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.                                   *
+*                                                                         *
+***************************************************************************
+"""
+
+__author__ = 'Nyall Dawson'
+__date__ = 'July 2016'
+__copyright__ = '(C) 2016, Nyall Dawson'
+
+# This will get replaced with a git SHA1 when you do a git archive323
+
+__revision__ = '$Format:%H$'
+
+import os
+
+from qgis.core import QgsGeometry, QgsWkbTypes
+
+from qgis.PyQt.QtGui import QIcon
+
+from processing.core.GeoAlgorithm import GeoAlgorithm
+from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
+from processing.core.parameters import ParameterVector, ParameterSelection, ParameterNumber
+from processing.core.outputs import OutputVector
+from processing.tools import dataobjects, vector
+
+pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
+
+
+class OffsetLine(GeoAlgorithm):
+
+    INPUT_LAYER = 'INPUT_LAYER'
+    OUTPUT_LAYER = 'OUTPUT_LAYER'
+    DISTANCE = 'DISTANCE'
+    SEGMENTS = 'SEGMENTS'
+    JOIN_STYLE = 'JOIN_STYLE'
+    MITRE_LIMIT = 'MITRE_LIMIT'
+
+    def defineCharacteristics(self):
+        self.name, self.i18n_name = self.trAlgorithm('Offset line')
+        self.group, self.i18n_group = self.trAlgorithm('Vector geometry tools')
+
+        self.addParameter(ParameterVector(self.INPUT_LAYER,
+                                          self.tr('Input layer'), [ParameterVector.VECTOR_TYPE_LINE]))
+        self.addParameter(ParameterNumber(self.DISTANCE,
+                                          self.tr('Distance'), default=10.0))
+        self.addParameter(ParameterNumber(self.SEGMENTS,
+                                          self.tr('Segments'), 1, default=8))
+        self.join_styles = [self.tr('Round'),
+                            'Mitre',
+                            'Bevel']
+        self.addParameter(ParameterSelection(
+            self.JOIN_STYLE,
+            self.tr('Join style'),
+            self.join_styles))
+        self.addParameter(ParameterNumber(self.MITRE_LIMIT,
+                                          self.tr('Mitre limit'), 1, default=2))
+
+        self.addOutput(OutputVector(self.OUTPUT_LAYER, self.tr('Offset')))
+
+    def processAlgorithm(self, progress):
+        layer = dataobjects.getObjectFromUri(
+            self.getParameterValue(self.INPUT_LAYER))
+
+        writer = self.getOutputFromName(
+            self.OUTPUT_LAYER).getVectorWriter(
+                layer.fields().toList(),
+                QgsWkbTypes.LineString,
+                layer.crs())
+
+        distance = self.getParameterValue(self.DISTANCE)
+        segments = int(self.getParameterValue(self.SEGMENTS))
+        join_style = self.getParameterValue(self.JOIN_STYLE) + 1
+        miter_limit = self.getParameterValue(self.MITRE_LIMIT)
+
+        features = vector.features(layer)
+        total = 100.0 / len(features)
+
+        for current, input_feature in enumerate(features):
+            output_feature = input_feature
+            input_geometry = input_feature.geometry()
+            if input_geometry:
+                output_geometry = input_geometry.offsetCurve(distance, segments, join_style, miter_limit)
+                if not output_geometry:
+                    raise GeoAlgorithmExecutionException(
+                        self.tr('Error calculating line offset'))
+
+                output_feature.setGeometry(output_geometry)
+
+            writer.addFeature(output_feature)
+            progress.setPercentage(int(current * total))
+
+        del writer
diff --git a/python/plugins/processing/algs/qgis/QGISAlgorithmProvider.py b/python/plugins/processing/algs/qgis/QGISAlgorithmProvider.py
@@ -150,6 +150,7 @@
 from .BoundingBox import BoundingBox
 from .Boundary import Boundary
 from .PointOnSurface import PointOnSurface
+from .OffsetLine import OffsetLine
 
 pluginPath = os.path.normpath(os.path.join(
     os.path.split(os.path.dirname(__file__))[0], os.pardir))
@@ -202,7 +203,8 @@ def __init__(self):
                         ReverseLineDirection(), SpatialIndex(), DefineProjection(),
                         RectanglesOvalsDiamondsVariable(),
                         RectanglesOvalsDiamondsFixed(), MergeLines(),
-                        BoundingBox(), Boundary(), PointOnSurface()
+                        BoundingBox(), Boundary(), PointOnSurface(),
+                        OffsetLine()
                         ]
 
         if hasMatplotlib:

diff --git a/python/plugins/processing/tests/testdata/expected/line_offset_bevel.gml b/python/plugins/processing/tests/testdata/expected/line_offset_bevel.gml
@@ -0,0 +1,48 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ogr:FeatureCollection
+     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+     xsi:schemaLocation="http://ogr.maptools.org/ line_offset_bevel.xsd"
+     xmlns:ogr="http://ogr.maptools.org/"
+     xmlns:gml="http://www.opengis.net/gml">
+  <gml:boundedBy>
+    <gml:Box>
+      <gml:coord><gml:X>-1</gml:X><gml:Y>-2.292893218813453</gml:Y></gml:coord>
+      <gml:coord><gml:X>10.29289321881345</gml:X><gml:Y>5.707106781186548</gml:Y></gml:coord>
+    </gml:Box>
+  </gml:boundedBy>
+
+  <gml:featureMember>
+    <ogr:line_offset_bevel fid="lines.0">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>6,3 8,3 8.292893218813452,3.707106781186547 10.292893218813452,5.707106781186548</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:line_offset_bevel>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:line_offset_bevel fid="lines.1">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>-1,0 1,0</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:line_offset_bevel>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:line_offset_bevel fid="lines.2">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>1,0 1,2 2,3</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:line_offset_bevel>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:line_offset_bevel fid="lines.3">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>3,2 5,2</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:line_offset_bevel>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:line_offset_bevel fid="lines.4">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>7,-2 10,-2</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:line_offset_bevel>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:line_offset_bevel fid="lines.5">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>5.292893218813452,-2.292893218813453 9.292893218813452,1.707106781186547</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:line_offset_bevel>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:line_offset_bevel fid="lines.6">
+    </ogr:line_offset_bevel>
+  </gml:featureMember>
+</ogr:FeatureCollection>
diff --git a/python/plugins/processing/tests/testdata/expected/line_offset_bevel.xsd b/python/plugins/processing/tests/testdata/expected/line_offset_bevel.xsd
@@ -0,0 +1,23 @@
+<?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="line_offset_bevel" type="ogr:line_offset_bevel_Type" substitutionGroup="gml:_Feature"/>
+<xs:complexType name="line_offset_bevel_Type">
+  <xs:complexContent>
+    <xs:extension base="gml:AbstractFeatureType">
+      <xs:sequence>
+        <xs:element name="geometryProperty" type="gml:LineStringPropertyType" nillable="true" minOccurs="0" maxOccurs="1"/>
+      </xs:sequence>
+    </xs:extension>
+  </xs:complexContent>
+</xs:complexType>
+</xs:schema>
diff --git a/python/plugins/processing/tests/testdata/expected/line_offset_mitre.gml b/python/plugins/processing/tests/testdata/expected/line_offset_mitre.gml
@@ -0,0 +1,48 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ogr:FeatureCollection
+     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+     xsi:schemaLocation="http://ogr.maptools.org/ line_offset_mitre.xsd"
+     xmlns:ogr="http://ogr.maptools.org/"
+     xmlns:gml="http://www.opengis.net/gml">
+  <gml:boundedBy>
+    <gml:Box>
+      <gml:coord><gml:X>-1</gml:X><gml:Y>-2.292893218813453</gml:Y></gml:coord>
+      <gml:coord><gml:X>10.29289321881345</gml:X><gml:Y>5.707106781186548</gml:Y></gml:coord>
+    </gml:Box>
+  </gml:boundedBy>
+
+  <gml:featureMember>
+    <ogr:line_offset_mitre fid="lines.0">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>6,3 8,3 8.0,3.414213562373094 10.292893218813452,5.707106781186548</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:line_offset_mitre>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:line_offset_mitre fid="lines.1">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>-1,0 1,0</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:line_offset_mitre>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:line_offset_mitre fid="lines.2">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>1,0 1,3 2,3</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:line_offset_mitre>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:line_offset_mitre fid="lines.3">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>3,2 5,2</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:line_offset_mitre>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:line_offset_mitre fid="lines.4">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>7,-2 10,-2</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:line_offset_mitre>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:line_offset_mitre fid="lines.5">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>5.292893218813452,-2.292893218813453 9.292893218813452,1.707106781186547</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:line_offset_mitre>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:line_offset_mitre fid="lines.6">
+    </ogr:line_offset_mitre>
+  </gml:featureMember>
+</ogr:FeatureCollection>
diff --git a/python/plugins/processing/tests/testdata/expected/line_offset_mitre.xsd b/python/plugins/processing/tests/testdata/expected/line_offset_mitre.xsd
@@ -0,0 +1,23 @@
+<?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="line_offset_mitre" type="ogr:line_offset_mitre_Type" substitutionGroup="gml:_Feature"/>
+<xs:complexType name="line_offset_mitre_Type">
+  <xs:complexContent>
+    <xs:extension base="gml:AbstractFeatureType">
+      <xs:sequence>
+        <xs:element name="geometryProperty" type="gml:LineStringPropertyType" nillable="true" minOccurs="0" maxOccurs="1"/>
+      </xs:sequence>
+    </xs:extension>
+  </xs:complexContent>
+</xs:complexType>
+</xs:schema>
diff --git a/python/plugins/processing/tests/testdata/expected/line_offset_round_negative.gml b/python/plugins/processing/tests/testdata/expected/line_offset_round_negative.gml
@@ -0,0 +1,48 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ogr:FeatureCollection
+     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+     xsi:schemaLocation="http://ogr.maptools.org/ line_offset_round_negative.xsd"
+     xmlns:ogr="http://ogr.maptools.org/"
+     xmlns:gml="http://www.opengis.net/gml">
+  <gml:boundedBy>
+    <gml:Box>
+      <gml:coord><gml:X>-1</gml:X><gml:Y>-4</gml:Y></gml:coord>
+      <gml:coord><gml:X>11.70710678118655</gml:X><gml:Y>4.292893218813452</gml:Y></gml:coord>
+    </gml:Box>
+  </gml:boundedBy>
+
+  <gml:featureMember>
+    <ogr:line_offset_round_negative fid="lines.0">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>11.707106781186548,4.292893218813452 10.0,2.585786437626905 10,2 9.98078528040323,1.804909677983872 9.923879532511286,1.61731656763491 9.831469612302543,1.444429766980398 9.707106781186548,1.292893218813453 9.555570233019605,1.168530387697455 9.38268343236509,1.076120467488713 9.195090322016128,1.01921471959677 9,1 6,1</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:line_offset_round_negative>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:line_offset_round_negative fid="lines.1">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>1,-2 -1,-2</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:line_offset_round_negative>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:line_offset_round_negative fid="lines.2">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>4,3 4,2 3.98078528040323,1.804909677983872 3.923879532511287,1.61731656763491 3.831469612302545,1.444429766980398 3.707106781186547,1.292893218813453 3.555570233019602,1.168530387697455 3.38268343236509,1.076120467488713 3.356009692300209,1.068029076900628 3.195090322016128,1.01921471959677 3,1 3,0</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:line_offset_round_negative>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:line_offset_round_negative fid="lines.3">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>5,0 3,0</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:line_offset_round_negative>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:line_offset_round_negative fid="lines.4">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>10,-4 7,-4</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:line_offset_round_negative>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:line_offset_round_negative fid="lines.5">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>10.707106781186548,0.292893218813453 6.707106781186548,-3.707106781186547</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:line_offset_round_negative>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:line_offset_round_negative fid="lines.6">
+    </ogr:line_offset_round_negative>
+  </gml:featureMember>
+</ogr:FeatureCollection>
diff --git a/python/plugins/processing/tests/testdata/expected/line_offset_round_negative.xsd b/python/plugins/processing/tests/testdata/expected/line_offset_round_negative.xsd
@@ -0,0 +1,23 @@
+<?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="line_offset_round_negative" type="ogr:line_offset_round_negative_Type" substitutionGroup="gml:_Feature"/>
+<xs:complexType name="line_offset_round_negative_Type">
+  <xs:complexContent>
+    <xs:extension base="gml:AbstractFeatureType">
+      <xs:sequence>
+        <xs:element name="geometryProperty" type="gml:LineStringPropertyType" nillable="true" minOccurs="0" maxOccurs="1"/>
+      </xs:sequence>
+    </xs:extension>
+  </xs:complexContent>
+</xs:complexType>
+</xs:schema>