Merge pull request #3441 from nyalldawson/simplify

Simplify features + fixes
qgis · Sep 1, 2016 · 88047cc · 88047cc
2 parents 798817e + 56b77db
commit 88047cc
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Showing 20 changed files with 446 additions and 127 deletions.
diff --git a/python/core/qgsmaptopixelgeometrysimplifier.sip b/python/core/qgsmaptopixelgeometrysimplifier.sip
@@ -43,6 +43,9 @@ class QgsMapToPixelSimplifier : QgsAbstractGeometrySimplifier
     //! Sets the local simplification algorithm of the vector layer managed
     void setSimplifyAlgorithm( SimplifyAlgorithm simplifyAlgorithm );
 
+    //! Returns a simplified version the specified geometry
+    virtual QgsGeometry simplify( const QgsGeometry& geometry ) const;
+
     //! Sets the tolerance of the vector layer managed
     void setTolerance( double value );
 

diff --git a/python/plugins/processing/algs/help/qgis.yaml b/python/plugins/processing/algs/help/qgis.yaml
@@ -429,6 +429,8 @@ qgis:setstyleforvectorlayer: >
 qgis:simplifygeometries: >
   This algorithm simplifies the geometries in a line or polygon layer. It creates a new layer with the same features as the ones in the input layer, but with geometries containing a lower number of vertices.
 
+  The algorithm gives a choice of simplification methods, including distance based (the "Douglas-Peucker" algorithm), area based ("Visvalingam" algorithm) and snapping geometries to grid.
+
 qgis:singlepartstomultipart:
 
 

diff --git a/python/plugins/processing/algs/qgis/SimplifyGeometries.py b/python/plugins/processing/algs/qgis/SimplifyGeometries.py
@@ -29,12 +29,13 @@
 
 from qgis.PyQt.QtGui import QIcon
 
-from qgis.core import Qgis, QgsFeature, QgsGeometry, QgsWkbTypes
+from qgis.core import Qgis, QgsFeature, QgsGeometry, QgsWkbTypes, QgsMapToPixelSimplifier
 
 from processing.core.GeoAlgorithm import GeoAlgorithm
 from processing.core.ProcessingLog import ProcessingLog
 from processing.core.parameters import ParameterVector
 from processing.core.parameters import ParameterNumber
+from processing.core.parameters import ParameterSelection
 from processing.core.outputs import OutputVector
 from processing.tools import dataobjects, vector
 
@@ -46,6 +47,7 @@ class SimplifyGeometries(GeoAlgorithm):
     INPUT = 'INPUT'
     TOLERANCE = 'TOLERANCE'
     OUTPUT = 'OUTPUT'
+    METHOD = 'METHOD'
 
     def getIcon(self):
         return QIcon(os.path.join(pluginPath, 'images', 'ftools', 'simplify.png'))
@@ -57,6 +59,13 @@ def defineCharacteristics(self):
         self.addParameter(ParameterVector(self.INPUT,
                                           self.tr('Input layer'),
                                           [ParameterVector.VECTOR_TYPE_POLYGON, ParameterVector.VECTOR_TYPE_LINE]))
+        self.methods = [self.tr('Distance (Douglas-Peucker)'),
+                        'Snap to grid',
+                        'Area (Visvalingam)']
+        self.addParameter(ParameterSelection(
+            self.METHOD,
+            self.tr('Simplification method'),
+            self.methods, default=0))
         self.addParameter(ParameterNumber(self.TOLERANCE,
                                           self.tr('Tolerance'), 0.0, 10000000.0, 1.0))
 
@@ -65,6 +74,7 @@ def defineCharacteristics(self):
     def processAlgorithm(self, progress):
         layer = dataobjects.getObjectFromUri(self.getParameterValue(self.INPUT))
         tolerance = self.getParameterValue(self.TOLERANCE)
+        method = self.getParameterValue(self.METHOD)
 
         pointsBefore = 0
         pointsAfter = 0
@@ -74,44 +84,27 @@ def processAlgorithm(self, progress):
 
         features = vector.features(layer)
         total = 100.0 / len(features)
-        for current, f in enumerate(features):
-            featGeometry = f.geometry()
-            attrs = f.attributes()
-            pointsBefore += self.geomVertexCount(featGeometry)
-            newGeometry = featGeometry.simplify(tolerance)
-            pointsAfter += self.geomVertexCount(newGeometry)
-            feature = QgsFeature()
-            feature.setGeometry(newGeometry)
-            feature.setAttributes(attrs)
-            writer.addFeature(feature)
+
+        if method != 0:
+            simplifier = QgsMapToPixelSimplifier(QgsMapToPixelSimplifier.SimplifyGeometry, tolerance, method)
+
+        for current, input_feature in enumerate(features):
+            out_feature = input_feature
+            if input_feature.geometry():
+                input_geometry = input_feature.geometry()
+                pointsBefore += input_geometry.geometry().nCoordinates()
+
+                if method == 0: # distance
+                    output_geometry = input_geometry.simplify(tolerance)
+                else:
+                    output_geometry = simplifier.simplify(input_geometry)
+
+                pointsAfter += output_geometry.geometry().nCoordinates()
+                out_feature.setGeometry(output_geometry)
+            writer.addFeature(out_feature)
             progress.setPercentage(int(current * total))
 
         del writer
 
         ProcessingLog.addToLog(ProcessingLog.LOG_INFO,
                                self.tr('Simplify: Input geometries have been simplified from %s to %s points' % (pointsBefore, pointsAfter)))
-
-    def geomVertexCount(self, geometry):
-        geomType = geometry.type()
-
-        if geomType == QgsWkbTypes.LineGeometry:
-            if geometry.isMultipart():
-                pointsList = geometry.asMultiPolyline()
-                points = sum(pointsList, [])
-            else:
-                points = geometry.asPolyline()
-            return len(points)
-        elif geomType == QgsWkbTypes.PolygonGeometry:
-            if geometry.isMultipart():
-                polylinesList = geometry.asMultiPolygon()
-                polylines = sum(polylinesList, [])
-            else:
-                polylines = geometry.asPolygon()
-
-            points = []
-            for l in polylines:
-                points.extend(l)
-
-            return len(points)
-        else:
-            return None
diff --git a/python/plugins/processing/tests/testdata/expected/simplify_grid_lines.gfs b/python/plugins/processing/tests/testdata/expected/simplify_grid_lines.gfs
@@ -0,0 +1,15 @@
+<GMLFeatureClassList>
+  <GMLFeatureClass>
+    <Name>simplify_grid_lines</Name>
+    <ElementPath>simplify_grid_lines</ElementPath>
+    <GeometryType>2</GeometryType>
+    <SRSName>EPSG:4326</SRSName>
+    <DatasetSpecificInfo>
+      <FeatureCount>4</FeatureCount>
+      <ExtentXMin>-0.08703</ExtentXMin>
+      <ExtentXMax>10.63163</ExtentXMax>
+      <ExtentYMin>-0.26248</ExtentYMin>
+      <ExtentYMax>4.98546</ExtentYMax>
+    </DatasetSpecificInfo>
+  </GMLFeatureClass>
+</GMLFeatureClassList>
diff --git a/python/plugins/processing/tests/testdata/expected/simplify_grid_lines.gml b/python/plugins/processing/tests/testdata/expected/simplify_grid_lines.gml
@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ogr:FeatureCollection
+     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+     xsi:schemaLocation=""
+     xmlns:ogr="http://ogr.maptools.org/"
+     xmlns:gml="http://www.opengis.net/gml">
+  <gml:boundedBy>
+    <gml:Box>
+      <gml:coord><gml:X>-0.08703339882121899</gml:X><gml:Y>-0.262475442043224</gml:Y></gml:coord>
+      <gml:coord><gml:X>10.63163064833006</gml:X><gml:Y>4.985461689587426</gml:Y></gml:coord>
+    </gml:Box>
+  </gml:boundedBy>
+
+  <gml:featureMember>
+    <ogr:simplify_grid_lines fid="1">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>-0.062278978388999,4.985461689587426 5.606483300589391,4.985461689587426</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:simplify_grid_lines>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:simplify_grid_lines fid="3">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>-0.087033398821219,2.782318271119842 2.314145383104125,2.757563850687622 7.388801571709235,4.713163064833005 9.789980353634579,2.757563850687622 10.631630648330059,2.757563850687622</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:simplify_grid_lines>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:simplify_grid_lines fid="2">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>0.061493123772101,-0.237721021611003 1.967583497053045,-0.262475442043224 4.34400785854617,2.262475442043221 6.448133595284873,-0.262475442043224 10.606876227897841,-0.188212180746563</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:simplify_grid_lines>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:simplify_grid_lines fid="4">
+    </ogr:simplify_grid_lines>
+  </gml:featureMember>
+</ogr:FeatureCollection>
diff --git a/python/plugins/processing/tests/testdata/expected/simplify_lines.gfs b/python/plugins/processing/tests/testdata/expected/simplify_lines.gfs
@@ -0,0 +1,15 @@
+<GMLFeatureClassList>
+  <GMLFeatureClass>
+    <Name>simplify_lines</Name>
+    <ElementPath>simplify_lines</ElementPath>
+    <GeometryType>2</GeometryType>
+    <SRSName>EPSG:4326</SRSName>
+    <DatasetSpecificInfo>
+      <FeatureCount>7</FeatureCount>
+      <ExtentXMin>-1.00000</ExtentXMin>
+      <ExtentXMax>11.00000</ExtentXMax>
+      <ExtentYMin>-3.00000</ExtentYMin>
+      <ExtentYMax>5.00000</ExtentYMax>
+    </DatasetSpecificInfo>
+  </GMLFeatureClass>
+</GMLFeatureClassList>
diff --git a/python/plugins/processing/tests/testdata/expected/simplify_lines.gml b/python/plugins/processing/tests/testdata/expected/simplify_lines.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=""
+     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>-3</gml:Y></gml:coord>
+      <gml:coord><gml:X>11</gml:X><gml:Y>5</gml:Y></gml:coord>
+    </gml:Box>
+  </gml:boundedBy>
+
+  <gml:featureMember>
+    <ogr:simplify_lines fid="lines.0">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>6,2 9,2 11,5</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:simplify_lines>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:simplify_lines fid="lines.1">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>-1,-1 1,-1</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:simplify_lines>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:simplify_lines fid="lines.2">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>2,0 3,3</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:simplify_lines>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:simplify_lines fid="lines.3">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>3,1 5,1</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:simplify_lines>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:simplify_lines fid="lines.4">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>7,-3 10,-3</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:simplify_lines>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:simplify_lines fid="lines.5">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>6,-3 10,1</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:simplify_lines>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:simplify_lines fid="lines.6">
+    </ogr:simplify_lines>
+  </gml:featureMember>
+</ogr:FeatureCollection>
diff --git a/python/plugins/processing/tests/testdata/expected/simplify_multilines.gfs b/python/plugins/processing/tests/testdata/expected/simplify_multilines.gfs
@@ -0,0 +1,15 @@
+<GMLFeatureClassList>
+  <GMLFeatureClass>
+    <Name>simplify_multilines</Name>
+    <ElementPath>simplify_multilines</ElementPath>
+    <GeometryType>5</GeometryType>
+    <SRSName>EPSG:4326</SRSName>
+    <DatasetSpecificInfo>
+      <FeatureCount>4</FeatureCount>
+      <ExtentXMin>-1.00000</ExtentXMin>
+      <ExtentXMax>5.58042</ExtentXMax>
+      <ExtentYMin>-1.00000</ExtentYMin>
+      <ExtentYMax>4.11977</ExtentYMax>
+    </DatasetSpecificInfo>
+  </GMLFeatureClass>
+</GMLFeatureClassList>
diff --git a/python/plugins/processing/tests/testdata/expected/simplify_multilines.gml b/python/plugins/processing/tests/testdata/expected/simplify_multilines.gml
@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ogr:FeatureCollection
+     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+     xsi:schemaLocation=""
+     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>-1</gml:Y></gml:coord>
+      <gml:coord><gml:X>5.58042226487524</gml:X><gml:Y>4.119769673704415</gml:Y></gml:coord>
+    </gml:Box>
+  </gml:boundedBy>
+
+  <gml:featureMember>
+    <ogr:simplify_multilines fid="lines.1">
+      <ogr:geometryProperty><gml:MultiLineString srsName="EPSG:4326"><gml:lineStringMember><gml:LineString><gml:coordinates>-1,-1 1,-1</gml:coordinates></gml:LineString></gml:lineStringMember></gml:MultiLineString></ogr:geometryProperty>
+    </ogr:simplify_multilines>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:simplify_multilines fid="lines.2">
+      <ogr:geometryProperty><gml:MultiLineString srsName="EPSG:4326"><gml:lineStringMember><gml:LineString><gml:coordinates>3,1 5,1</gml:coordinates></gml:LineString></gml:lineStringMember><gml:lineStringMember><gml:LineString><gml:coordinates>5.024184261036468,2.414779270633399 5,1</gml:coordinates></gml:LineString></gml:lineStringMember></gml:MultiLineString></ogr:geometryProperty>
+    </ogr:simplify_multilines>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:simplify_multilines fid="lines.3">
+    </ogr:simplify_multilines>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:simplify_multilines fid="lines.4">
+      <ogr:geometryProperty><gml:MultiLineString srsName="EPSG:4326"><gml:lineStringMember><gml:LineString><gml:coordinates>2,0 3,3</gml:coordinates></gml:LineString></gml:lineStringMember><gml:lineStringMember><gml:LineString><gml:coordinates>2.944337811900192,4.04721689059501 5.459500959692898,4.119769673704415</gml:coordinates></gml:LineString></gml:lineStringMember><gml:lineStringMember><gml:LineString><gml:coordinates>3,3 5.58042226487524,2.946833013435702</gml:coordinates></gml:LineString></gml:lineStringMember></gml:MultiLineString></ogr:geometryProperty>
+    </ogr:simplify_multilines>
+  </gml:featureMember>
+</ogr:FeatureCollection>
diff --git a/python/plugins/processing/tests/testdata/expected/simplify_vis_lines.gfs b/python/plugins/processing/tests/testdata/expected/simplify_vis_lines.gfs
@@ -0,0 +1,15 @@
+<GMLFeatureClassList>
+  <GMLFeatureClass>
+    <Name>simplify_vis_lines</Name>
+    <ElementPath>simplify_vis_lines</ElementPath>
+    <GeometryType>2</GeometryType>
+    <SRSName>EPSG:4326</SRSName>
+    <DatasetSpecificInfo>
+      <FeatureCount>4</FeatureCount>
+      <ExtentXMin>-0.08703</ExtentXMin>
+      <ExtentXMax>10.63163</ExtentXMax>
+      <ExtentYMin>-0.26248</ExtentYMin>
+      <ExtentYMax>4.98546</ExtentYMax>
+    </DatasetSpecificInfo>
+  </GMLFeatureClass>
+</GMLFeatureClassList>
diff --git a/python/plugins/processing/tests/testdata/expected/simplify_vis_lines.gml b/python/plugins/processing/tests/testdata/expected/simplify_vis_lines.gml
@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ogr:FeatureCollection
+     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+     xsi:schemaLocation=""
+     xmlns:ogr="http://ogr.maptools.org/"
+     xmlns:gml="http://www.opengis.net/gml">
+  <gml:boundedBy>
+    <gml:Box>
+      <gml:coord><gml:X>-0.08703339882121899</gml:X><gml:Y>-0.262475442043224</gml:Y></gml:coord>
+      <gml:coord><gml:X>10.63163064833006</gml:X><gml:Y>4.985461689587426</gml:Y></gml:coord>
+    </gml:Box>
+  </gml:boundedBy>
+
+  <gml:featureMember>
+    <ogr:simplify_vis_lines fid="1">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>-0.062278978388999,4.985461689587426 5.606483300589391,4.985461689587426</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:simplify_vis_lines>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:simplify_vis_lines fid="3">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>-0.087033398821219,2.782318271119842 5.284675834970531,2.782318271119842 7.388801571709235,4.713163064833005 10.631630648330059,2.757563850687622</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:simplify_vis_lines>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:simplify_vis_lines fid="2">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>0.061493123772101,-0.237721021611003 1.967583497053045,-0.262475442043224 4.34400785854617,2.262475442043221 6.448133595284873,-0.262475442043224 10.606876227897841,-0.188212180746563</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:simplify_vis_lines>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:simplify_vis_lines fid="4">
+    </ogr:simplify_vis_lines>
+  </gml:featureMember>
+</ogr:FeatureCollection>
diff --git a/python/plugins/processing/tests/testdata/qgis_algorithm_tests.yaml b/python/plugins/processing/tests/testdata/qgis_algorithm_tests.yaml
@@ -916,3 +916,52 @@ tests:
         name: expected/extract_nodes_lines.gml
         type: vector
 
+  - algorithm: qgis:simplifygeometries
+    name: Simplify (lines)
+    params:
+      INPUT:
+        name: lines.gml
+        type: vector
+      TOLERANCE: 1.0
+    results:
+      OUTPUT:
+        name: expected/simplify_lines.gml
+        type: vector
+
+  - algorithm: qgis:simplifygeometries
+    name: Simplify (multilines)
+    params:
+      INPUT:
+        name: multilines.gml
+        type: vector
+      TOLERANCE: 1.0
+    results:
+      OUTPUT:
+        name: expected/simplify_multilines.gml
+        type: vector
+
+  - algorithm: qgis:simplifygeometries
+    name: Simplify (visval)
+    params:
+      INPUT:
+        name: simplify_lines.gml
+        type: vector
+      METHOD: '2'
+      TOLERANCE: 1.0
+    results:
+      OUTPUT:
+        name: expected/simplify_vis_lines.gml
+        type: vector
+
+  - algorithm: qgis:simplifygeometries
+    name: Simplify (grid)
+    params:
+      INPUT:
+        name: simplify_lines.gml
+        type: vector
+      METHOD: '1'
+      TOLERANCE: 5.0
+    results:
+      OUTPUT:
+        name: expected/simplify_grid_lines.gml
+        type: vector