Python QgsGeometry.convexHull方法代码示例

# 需要导入模块: from qgis.core import QgsGeometry [as 别名]
# 或者: from qgis.core.QgsGeometry import convexHull [as 别名]
    def processAlgorithm(self, progress):
        layer = dataobjects.getObjectFromUri(self.getParameterValue(self.INPUT))

        buf = self.getParameterValue(self.BUFFER)

        writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(
            layer.pendingFields().toList(), QGis.WKBPolygon, layer.crs())

        inFeat = QgsFeature()
        outFeat = QgsFeature()
        extent = layer.extent()
        extraX = extent.height() * (buf / 100.0)
        extraY = extent.width() * (buf / 100.0)
        height = extent.height()
        width = extent.width()
        c = voronoi.Context()
        pts = []
        ptDict = {}
        ptNdx = -1

        features = vector.features(layer)
        for inFeat in features:
            geom = QgsGeometry(inFeat.geometry())
            point = geom.asPoint()
            x = point.x() - extent.xMinimum()
            y = point.y() - extent.yMinimum()
            pts.append((x, y))
            ptNdx += 1
            ptDict[ptNdx] = inFeat.id()

        if len(pts) < 3:
            raise GeoAlgorithmExecutionException(
                self.tr('Input file should contain at least 3 points. Choose '
                        'another file and try again.'))

        uniqueSet = Set(item for item in pts)
        ids = [pts.index(item) for item in uniqueSet]
        sl = voronoi.SiteList([voronoi.Site(i[0], i[1], sitenum=j) for (j,
                              i) in enumerate(uniqueSet)])
        voronoi.voronoi(sl, c)
        inFeat = QgsFeature()

        current = 0
        total = 100.0 / float(len(c.polygons))

        for (site, edges) in c.polygons.iteritems():
            request = QgsFeatureRequest().setFilterFid(ptDict[ids[site]])
            inFeat = layer.getFeatures(request).next()
            lines = self.clip_voronoi(edges, c, width, height, extent, extraX, extraY)

            geom = QgsGeometry.fromMultiPoint(lines)
            geom = QgsGeometry(geom.convexHull())
            outFeat.setGeometry(geom)
            outFeat.setAttributes(inFeat.attributes())
            writer.addFeature(outFeat)

            current += 1
            progress.setPercentage(int(current * total))

        del writer

# 需要导入模块: from qgis.core import QgsGeometry [as 别名]
# 或者: from qgis.core.QgsGeometry import convexHull [as 别名]
    def createFeature(self, feedback, feature_id, type, geometries, class_field=None):
        attrs = [feature_id]
        if class_field is not None:
            attrs.append(class_field)

        multi_point = QgsMultiPoint()

        for g in geometries:
            if feedback.isCanceled():
                break

            vid = QgsVertexId()
            while True:
                if feedback.isCanceled():
                    break
                found, point = g.constGet().nextVertex(vid)
                if found:
                    multi_point.addGeometry(point)
                else:
                    break

        geometry = QgsGeometry(multi_point)
        output_geometry = None
        if type == 0:
            # envelope
            rect = geometry.boundingBox()
            output_geometry = QgsGeometry.fromRect(rect)
            attrs.append(rect.width())
            attrs.append(rect.height())
            attrs.append(rect.area())
            attrs.append(rect.perimeter())
        elif type == 1:
            # oriented rect
            output_geometry, area, angle, width, height = geometry.orientedMinimumBoundingBox()
            attrs.append(width)
            attrs.append(height)
            attrs.append(angle)
            attrs.append(area)
            attrs.append(2 * width + 2 * height)
        elif type == 2:
            # circle
            output_geometry, center, radius = geometry.minimalEnclosingCircle(segments=72)
            attrs.append(radius)
            attrs.append(math.pi * radius * radius)
        elif type == 3:
            # convex hull
            output_geometry = geometry.convexHull()
            attrs.append(output_geometry.constGet().area())
            attrs.append(output_geometry.constGet().perimeter())
        f = QgsFeature()
        f.setAttributes(attrs)
        f.setGeometry(output_geometry)
        return f

# 需要导入模块: from qgis.core import QgsGeometry [as 别名]
# 或者: from qgis.core.QgsGeometry import convexHull [as 别名]
 def voronoi_polygons( self ):
   vprovider = self.vlayer.dataProvider()
   writer = QgsVectorFileWriter( self.myName, self.myEncoding, vprovider.fields(),
                                 QGis.WKBPolygon, vprovider.crs() )
   inFeat = QgsFeature()
   outFeat = QgsFeature()
   extent = self.vlayer.extent()
   extraX = extent.height() * ( self.myParam / 100.00 )
   extraY = extent.width() * ( self.myParam / 100.00 )
   height = extent.height()
   width = extent.width()
   c = voronoi.Context()
   pts = []
   ptDict = {}
   ptNdx = -1
   fit = vprovider.getFeatures()
   while fit.nextFeature( inFeat ):
     geom = QgsGeometry( inFeat.geometry() )
     point = geom.asPoint()
     x = point.x() - extent.xMinimum()
     y = point.y() - extent.yMinimum()
     pts.append( ( x, y ) )
     ptNdx +=1
     ptDict[ ptNdx ] = inFeat.id()
   self.vlayer = None
   if len( pts ) < 3:
     return False
   uniqueSet = Set( item for item in pts )
   ids = [ pts.index( item ) for item in uniqueSet ]
   sl = voronoi.SiteList( [ voronoi.Site( i[ 0 ], i[ 1 ], sitenum=j ) for j, i in enumerate( uniqueSet ) ] )
   voronoi.voronoi( sl, c )
   inFeat = QgsFeature()
   nFeat = len( c.polygons )
   nElement = 0
   self.emit( SIGNAL( "runStatus( PyQt_PyObject )" ), 0 )
   self.emit( SIGNAL( "runRange( PyQt_PyObject )" ), ( 0, nFeat ) )
   for site, edges in c.polygons.iteritems():
     vprovider.getFeatures( QgsFeatureRequest().setFilterFid( ptDict[ ids[ site ] ] ) ).nextFeature( inFeat )
     lines = self.clip_voronoi( edges, c, width, height, extent, extraX, extraY )
     geom = QgsGeometry.fromMultiPoint( lines )
     geom = QgsGeometry( geom.convexHull() )
     outFeat.setGeometry( geom )
     outFeat.setAttributes( inFeat.attributes() )
     writer.addFeature( outFeat )
     nElement += 1
     self.emit( SIGNAL( "runStatus( PyQt_PyObject )" ), nElement )
   del writer
   return True

# 需要导入模块: from qgis.core import QgsGeometry [as 别名]
# 或者: from qgis.core.QgsGeometry import convexHull [as 别名]
    def on_btnRun_clicked(self):
                
        if self.inputfile == '':
            QMessageBox.critical(self,'Map Creator',
                                 'Please specify input coordinate file.')
            return
        
        if self.outputfile == '':
            QMessageBox.critical(self,'Map Creator',
                                 'Please specify output shapefile.')
            return
        
        self.setCursor(Qt.WaitCursor)

        #Open coordinate input file
        f = open(self.inputfile, 'r')
        lines = f.readlines()
        f.close()
        header = lines[0].split(',')[0]
        totfeat = len(lines) - 1
        lines.pop(0)
        lines.reverse() 
        
        #Create vector layer
        basename = os.path.basename(self.outputfile)
        vlayer = QgsVectorLayer("Polygon", basename, "memory")
        vprovider = vlayer.dataProvider()
        fld = QgsField(header,QVariant.String)
        flds = QgsFields()
        flds.append(fld)
        vprovider.addAttributes([fld])
        vlayer.startEditing()
                
        hull = []
        for cnt, line in enumerate(lines):
            line = line.rstrip().split(',')
            numcoords = int((len(line) - 1) / 2)
            hull[:] = []
            geom = QgsGeometry()
            feat = QgsFeature()
            feat.setFields(flds)
            for i in range(numcoords):
                hull.append(QgsPoint(float(line[i*2+1]),float(line[i*2+2])))
            geom = geom.fromMultiPoint(hull)
            geom = geom.convexHull()
            feat.setGeometry(geom)
            feat.setAttribute(header,str(line[0]))
            result = vlayer.addFeature(feat)
            if not result:
                self.setCursor(Qt.ArrowCursor)
                QMessageBox.critical(self,'Map Creator', 'Processing error.')
                return
            self.ui.ProgressBar.setValue(float(cnt+1)/float(totfeat) * 100.0)
            QApplication.processEvents()  
        vlayer.commitChanges()
        vlayer.updateExtents()
        
        #Write the output shapefile
        if os.path.exists(self.outputfile):
            QgsVectorFileWriter.deleteShapeFile(self.outputfile)
        result = QgsVectorFileWriter.writeAsVectorFormat(vlayer, 
                                                         self.outputfile, 
                                                         'utf-8', 
                                                         vlayer.crs())
                
        if result != QgsVectorFileWriter.NoError:
            QMessageBox.critical(self,'Map Creator','Error creating shapefile.')
        else: #Ask to add shapfile to map
            name = QFileInfo(self.outputfile).completeBaseName()
            result = QMessageBox.question(self,'Map Creator',
                                          'Add shapefile to map?',
                                          QMessageBox.Yes,
                                          QMessageBox.No)
            if result == QMessageBox.Yes:
                self.iface.addVectorLayer(self.outputfile, name, 'ogr')
                
        self.setCursor(Qt.ArrowCursor)

# 需要导入模块: from qgis.core import QgsGeometry [as 别名]
# 或者: from qgis.core.QgsGeometry import convexHull [as 别名]
    def processAlgorithm(self, parameters, context, feedback):
        source = self.parameterAsSource(parameters, self.INPUT, context)
        buf = self.parameterAsDouble(parameters, self.BUFFER, context)
        (sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
                                               source.fields(), QgsWkbTypes.Polygon, source.sourceCrs())

        outFeat = QgsFeature()
        extent = source.sourceExtent()
        extraX = extent.height() * (buf / 100.0)
        extraY = extent.width() * (buf / 100.0)
        height = extent.height()
        width = extent.width()
        c = voronoi.Context()
        pts = []
        ptDict = {}
        ptNdx = -1

        features = source.getFeatures()
        total = 100.0 / source.featureCount() if source.featureCount() else 0
        for current, inFeat in enumerate(features):
            if feedback.isCanceled():
                break
            geom = inFeat.geometry()
            point = geom.asPoint()
            x = point.x() - extent.xMinimum()
            y = point.y() - extent.yMinimum()
            pts.append((x, y))
            ptNdx += 1
            ptDict[ptNdx] = inFeat.id()
            feedback.setProgress(int(current * total))

        if len(pts) < 3:
            raise QgsProcessingException(
                self.tr('Input file should contain at least 3 points. Choose '
                        'another file and try again.'))

        uniqueSet = set(item for item in pts)
        ids = [pts.index(item) for item in uniqueSet]
        sl = voronoi.SiteList([voronoi.Site(i[0], i[1], sitenum=j) for (j,
                                                                        i) in enumerate(uniqueSet)])
        voronoi.voronoi(sl, c)
        inFeat = QgsFeature()

        current = 0
        if len(c.polygons) == 0:
            raise QgsProcessingException(
                self.tr('There were no polygons created.'))

        total = 100.0 / len(c.polygons)

        for (site, edges) in list(c.polygons.items()):
            if feedback.isCanceled():
                break

            request = QgsFeatureRequest().setFilterFid(ptDict[ids[site]])
            inFeat = next(source.getFeatures(request))
            lines = self.clip_voronoi(edges, c, width, height, extent, extraX, extraY)

            geom = QgsGeometry.fromMultiPoint(lines)
            geom = QgsGeometry(geom.convexHull())
            outFeat.setGeometry(geom)
            outFeat.setAttributes(inFeat.attributes())
            sink.addFeature(outFeat, QgsFeatureSink.FastInsert)

            current += 1
            feedback.setProgress(int(current * total))

        return {self.OUTPUT: dest_id}

# 需要导入模块: from qgis.core import QgsGeometry [as 别名]
# 或者: from qgis.core.QgsGeometry import convexHull [as 别名]
    def processAlgorithm(self, progress):
        layer = dataobjects.getObjectFromUri(
            self.getParameterValue(self.INPUT))
        useField = self.getParameterValue(self.METHOD) == 1
        fieldName = self.getParameterValue(self.FIELD)

        f = QgsField('value', QVariant.String, '', 255)
        if useField:
            index = layer.fieldNameIndex(fieldName)
            fType = layer.pendingFields()[index].type()
            if fType == QVariant.Int:
                f.setType(QVariant.Int)
                f.setLength(20)
            elif fType == QVariant.Double:
                f.setType(QVariant.Double)
                f.setLength(20)
                f.setPrecision(6)
            else:
                f.setType(QVariant.String)
                f.setLength(255)

        fields = [QgsField('id', QVariant.Int, '', 20),
                  f,
                  QgsField('area', QVariant.Double, '', 20, 6),
                  QgsField('perim', QVariant.Double, '', 20, 6)
                 ]

        writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(
            fields, QGis.WKBPolygon, layer.dataProvider().crs())

        outFeat = QgsFeature()
        inGeom = QgsGeometry()
        outGeom = QgsGeometry()

        current = 0

        fid = 0
        val = None
        features = vector.features(layer)
        if useField:
            unique = layer.uniqueValues(index)
            total = 100.0 / (len(features) * len(unique))
            for i in unique:
                first = True
                hull = []
                features = vector.features(layer)
                for f in features:
                    idVar = f[fieldName]
                    if unicode(idVar).strip() == unicode(i).strip():
                        if first:
                            val = idVar
                            first = False

                        inGeom = QgsGeometry(f.geometry())
                        points = vector.extractPoints(inGeom)
                        hull.extend(points)
                    current += 1
                    progress.setPercentage(int(current * total))

                if len(hull) >= 3:
                    tmpGeom = QgsGeometry(outGeom.fromMultiPoint(hull))
                    try:
                        outGeom = tmpGeom.convexHull()
                        (area, perim) = vector.simpleMeasure(outGeom)
                        outFeat.setGeometry(outGeom)
                        outFeat.setAttributes([fid, val, area, perim])
                        writer.addFeature(outFeat)
                    except:
                        raise GeoAlgorithmExecutionException(
                            self.tr('Exception while computing convex hull'))
                fid += 1
        else:
            hull = []
            total = 100.0 / float(layer.featureCount())
            features = vector.features(layer)
            for f in features:
                inGeom = QgsGeometry(f.geometry())
                points = vector.extractPoints(inGeom)
                hull.extend(points)
                current += 1
                progress.setPercentage(int(current * total))

            tmpGeom = QgsGeometry(outGeom.fromMultiPoint(hull))
            try:
                outGeom = tmpGeom.convexHull()
                (area, perim) = vector.simpleMeasure(outGeom)
                outFeat.setGeometry(outGeom)
                outFeat.setAttributes([0, 'all', area, perim])
                writer.addFeature(outFeat)
            except:
                raise GeoAlgorithmExecutionException(
                    self.tr('Exception while computing convex hull'))

        del writer

# 需要导入模块: from qgis.core import QgsGeometry [as 别名]
# 或者: from qgis.core.QgsGeometry import convexHull [as 别名]
    def processAlgorithm(self, parameters, context, feedback):
        layer = QgsProcessingUtils.mapLayerFromString(self.getParameterValue(self.INPUT), context)

        buf = self.getParameterValue(self.BUFFER)

        writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(layer.fields(), QgsWkbTypes.Polygon,
                                                                     layer.crs(), context)

        outFeat = QgsFeature()
        extent = layer.extent()
        extraX = extent.height() * (buf / 100.0)
        extraY = extent.width() * (buf / 100.0)
        height = extent.height()
        width = extent.width()
        c = voronoi.Context()
        pts = []
        ptDict = {}
        ptNdx = -1

        features = QgsProcessingUtils.getFeatures(layer, context)
        total = 100.0 / layer.featureCount() if layer.featureCount() else 0
        for current, inFeat in enumerate(features):
            geom = inFeat.geometry()
            point = geom.asPoint()
            x = point.x() - extent.xMinimum()
            y = point.y() - extent.yMinimum()
            pts.append((x, y))
            ptNdx += 1
            ptDict[ptNdx] = inFeat.id()
            feedback.setProgress(int(current * total))

        if len(pts) < 3:
            raise GeoAlgorithmExecutionException(
                self.tr('Input file should contain at least 3 points. Choose '
                        'another file and try again.'))

        uniqueSet = set(item for item in pts)
        ids = [pts.index(item) for item in uniqueSet]
        sl = voronoi.SiteList([voronoi.Site(i[0], i[1], sitenum=j) for (j,
                                                                        i) in enumerate(uniqueSet)])
        voronoi.voronoi(sl, c)
        inFeat = QgsFeature()

        current = 0
        if len(c.polygons) == 0:
            raise GeoAlgorithmExecutionException(
                self.tr('There were no polygons created.'))

        total = 100.0 / len(c.polygons)

        for (site, edges) in list(c.polygons.items()):
            request = QgsFeatureRequest().setFilterFid(ptDict[ids[site]])
            inFeat = next(layer.getFeatures(request))
            lines = self.clip_voronoi(edges, c, width, height, extent, extraX, extraY)

            geom = QgsGeometry.fromMultiPoint(lines)
            geom = QgsGeometry(geom.convexHull())
            outFeat.setGeometry(geom)
            outFeat.setAttributes(inFeat.attributes())
            writer.addFeature(outFeat, QgsFeatureSink.FastInsert)

            current += 1
            feedback.setProgress(int(current * total))

        del writer

# 需要导入模块: from qgis.core import QgsGeometry [as 别名]
# 或者: from qgis.core.QgsGeometry import convexHull [as 别名]
    def processAlgorithm(self, parameters, context, feedback):
        source = self.parameterAsSource(parameters, self.INPUT, context)
        fieldName = self.parameterAsString(parameters, self.FIELD, context)
        useField = bool(fieldName)

        field_index = None
        f = QgsField('value', QVariant.String, '', 255)
        if useField:
            field_index = source.fields().lookupField(fieldName)
            fType = source.fields()[field_index].type()
            if fType in [QVariant.Int, QVariant.UInt, QVariant.LongLong, QVariant.ULongLong]:
                f.setType(fType)
                f.setLength(20)
            elif fType == QVariant.Double:
                f.setType(QVariant.Double)
                f.setLength(20)
                f.setPrecision(6)
            else:
                f.setType(QVariant.String)
                f.setLength(255)

        fields = QgsFields()
        fields.append(QgsField('id', QVariant.Int, '', 20))
        fields.append(f)
        fields.append(QgsField('area', QVariant.Double, '', 20, 6))
        fields.append(QgsField('perim', QVariant.Double, '', 20, 6))

        (sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
                                               fields, QgsWkbTypes.Polygon, source.sourceCrs())

        outFeat = QgsFeature()
        outGeom = QgsGeometry()

        fid = 0
        val = None
        if useField:
            unique = source.uniqueValues(field_index)
            current = 0
            total = 100.0 / (source.featureCount() * len(unique)) if source.featureCount() else 1
            for i in unique:
                if feedback.isCanceled():
                    break

                first = True
                hull = []
                features = source.getFeatures(QgsFeatureRequest().setSubsetOfAttributes([field_index]))
                for f in features:
                    if feedback.isCanceled():
                        break

                    idVar = f.attributes()[field_index]
                    if str(idVar).strip() == str(i).strip():
                        if first:
                            val = idVar
                            first = False

                        inGeom = f.geometry()
                        points = vector.extractPoints(inGeom)
                        hull.extend(points)
                    current += 1
                    feedback.setProgress(int(current * total))

                if len(hull) >= 3:
                    tmpGeom = QgsGeometry(outGeom.fromMultiPoint(hull))
                    try:
                        outGeom = tmpGeom.convexHull()
                        if outGeom:
                            area = outGeom.geometry().area()
                            perim = outGeom.geometry().perimeter()
                        else:
                            area = NULL
                            perim = NULL
                        outFeat.setGeometry(outGeom)
                        outFeat.setAttributes([fid, val, area, perim])
                        sink.addFeature(outFeat, QgsFeatureSink.FastInsert)
                    except:
                        raise QgsProcessingException(
                            self.tr('Exception while computing convex hull'))
                fid += 1
        else:
            hull = []
            total = 100.0 / source.featureCount() if source.featureCount() else 1
            features = source.getFeatures(QgsFeatureRequest().setSubsetOfAttributes([]))
            for current, f in enumerate(features):
                if feedback.isCanceled():
                    break

                inGeom = f.geometry()
                points = vector.extractPoints(inGeom)
                hull.extend(points)
                feedback.setProgress(int(current * total))

            tmpGeom = QgsGeometry(outGeom.fromMultiPoint(hull))
            try:
                outGeom = tmpGeom.convexHull()
                if outGeom:
                    area = outGeom.geometry().area()
                    perim = outGeom.geometry().perimeter()
                else:
                    area = NULL
#.........这里部分代码省略.........

# 需要导入模块: from qgis.core import QgsGeometry [as 别名]
# 或者: from qgis.core.QgsGeometry import convexHull [as 别名]
    def processAlgorithm(self, parameters, context, feedback):
        layer = QgsProcessingUtils.mapLayerFromString(self.getParameterValue(self.INPUT), context)
        useField = self.getParameterValue(self.METHOD) == 1
        fieldName = self.getParameterValue(self.FIELD)

        f = QgsField('value', QVariant.String, '', 255)
        if useField:
            index = layer.fields().lookupField(fieldName)
            fType = layer.fields()[index].type()
            if fType in [QVariant.Int, QVariant.UInt, QVariant.LongLong, QVariant.ULongLong]:
                f.setType(fType)
                f.setLength(20)
            elif fType == QVariant.Double:
                f.setType(QVariant.Double)
                f.setLength(20)
                f.setPrecision(6)
            else:
                f.setType(QVariant.String)
                f.setLength(255)

        fields = QgsFields()
        fields.append(QgsField('id', QVariant.Int, '', 20))
        fields.append(f)
        fields.append(QgsField('area', QVariant.Double, '', 20, 6))
        fields.append(QgsField('perim', QVariant.Double, '', 20, 6))

        writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(fields, QgsWkbTypes.Polygon, layer.crs(), context)

        outFeat = QgsFeature()
        inGeom = QgsGeometry()
        outGeom = QgsGeometry()

        fid = 0
        val = None
        features = QgsProcessingUtils.getFeatures(layer, context)
        if useField:
            unique = layer.uniqueValues(index)
            current = 0
            total = 100.0 / (layer.featureCount() * len(unique)) if layer.featureCount() else 1
            for i in unique:
                first = True
                hull = []
                features = QgsProcessingUtils.getFeatures(layer, context)
                for f in features:
                    idVar = f[fieldName]
                    if str(idVar).strip() == str(i).strip():
                        if first:
                            val = idVar
                            first = False

                        inGeom = f.geometry()
                        points = vector.extractPoints(inGeom)
                        hull.extend(points)
                    current += 1
                    feedback.setProgress(int(current * total))

                if len(hull) >= 3:
                    tmpGeom = QgsGeometry(outGeom.fromMultiPoint(hull))
                    try:
                        outGeom = tmpGeom.convexHull()
                        (area, perim) = vector.simpleMeasure(outGeom)
                        outFeat.setGeometry(outGeom)
                        outFeat.setAttributes([fid, val, area, perim])
                        writer.addFeature(outFeat, QgsFeatureSink.FastInsert)
                    except:
                        raise GeoAlgorithmExecutionException(
                            self.tr('Exception while computing convex hull'))
                fid += 1
        else:
            hull = []
            total = 100.0 / layer.featureCount() if layer.featureCount() else 1
            features = QgsProcessingUtils.getFeatures(layer, context)
            for current, f in enumerate(features):
                inGeom = f.geometry()
                points = vector.extractPoints(inGeom)
                hull.extend(points)
                feedback.setProgress(int(current * total))

            tmpGeom = QgsGeometry(outGeom.fromMultiPoint(hull))
            try:
                outGeom = tmpGeom.convexHull()
                (area, perim) = vector.simpleMeasure(outGeom)
                outFeat.setGeometry(outGeom)
                outFeat.setAttributes([0, 'all', area, perim])
                writer.addFeature(outFeat, QgsFeatureSink.FastInsert)
            except:
                raise GeoAlgorithmExecutionException(
                    self.tr('Exception while computing convex hull'))

        del writer

# 需要导入模块: from qgis.core import QgsGeometry [as 别名]
# 或者: from qgis.core.QgsGeometry import convexHull [as 别名]
    def processAlgorithm(self, progress):
        layer = dataobjects.getObjectFromUri(self.getParameterValue(self.INPUT))
        useField = self.getParameterValue(self.METHOD) == 1
        fieldName = self.getParameterValue(self.FIELD)

        f = QgsField("value", QVariant.String, "", 255)
        if useField:
            index = layer.fields().lookupField(fieldName)
            fType = layer.fields()[index].type()
            if fType in [QVariant.Int, QVariant.UInt, QVariant.LongLong, QVariant.ULongLong]:
                f.setType(fType)
                f.setLength(20)
            elif fType == QVariant.Double:
                f.setType(QVariant.Double)
                f.setLength(20)
                f.setPrecision(6)
            else:
                f.setType(QVariant.String)
                f.setLength(255)

        fields = [
            QgsField("id", QVariant.Int, "", 20),
            f,
            QgsField("area", QVariant.Double, "", 20, 6),
            QgsField("perim", QVariant.Double, "", 20, 6),
        ]

        writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(fields, QgsWkbTypes.Polygon, layer.crs())

        outFeat = QgsFeature()
        inGeom = QgsGeometry()
        outGeom = QgsGeometry()

        fid = 0
        val = None
        features = vector.features(layer)
        if useField:
            unique = layer.uniqueValues(index)
            current = 0
            total = 100.0 / (len(features) * len(unique))
            for i in unique:
                first = True
                hull = []
                features = vector.features(layer)
                for f in features:
                    idVar = f[fieldName]
                    if str(idVar).strip() == str(i).strip():
                        if first:
                            val = idVar
                            first = False

                        inGeom = f.geometry()
                        points = vector.extractPoints(inGeom)
                        hull.extend(points)
                    current += 1
                    progress.setPercentage(int(current * total))

                if len(hull) >= 3:
                    tmpGeom = QgsGeometry(outGeom.fromMultiPoint(hull))
                    try:
                        outGeom = tmpGeom.convexHull()
                        (area, perim) = vector.simpleMeasure(outGeom)
                        outFeat.setGeometry(outGeom)
                        outFeat.setAttributes([fid, val, area, perim])
                        writer.addFeature(outFeat)
                    except:
                        raise GeoAlgorithmExecutionException(self.tr("Exception while computing convex hull"))
                fid += 1
        else:
            hull = []
            total = 100.0 / layer.featureCount()
            features = vector.features(layer)
            for current, f in enumerate(features):
                inGeom = f.geometry()
                points = vector.extractPoints(inGeom)
                hull.extend(points)
                progress.setPercentage(int(current * total))

            tmpGeom = QgsGeometry(outGeom.fromMultiPoint(hull))
            try:
                outGeom = tmpGeom.convexHull()
                (area, perim) = vector.simpleMeasure(outGeom)
                outFeat.setGeometry(outGeom)
                outFeat.setAttributes([0, "all", area, perim])
                writer.addFeature(outFeat)
            except:
                raise GeoAlgorithmExecutionException(self.tr("Exception while computing convex hull"))

        del writer