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1e13d733c2
initAlgorithm() method This allows 2 benefits: - algorithms can be subclassed and have subclasses add additional parameters/outputs to the algorithm. With the previous approach of declaring parameters/outputs in the constructor, it's not possible to call virtual methods to add additional parameters/ outputs (since you can't call virtual methods from a constructor). - initAlgorithm takes a variant map argument, allowing the algorithm to dynamically adjust its declared parameters and outputs according to this configuration map. This potentially allows model algorithms which can be configured to have variable numbers of parameters and outputs at run time. E.g. a "router" algorithm which directs features to one of any number of output sinks depending on some user configured criteria.
108 lines
4.2 KiB
Python
108 lines
4.2 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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SelectByAttributeSum.py
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---------------------
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Date : April 2015
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Copyright : (C) 2015 by Alexander Bruy
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Email : alexander dot bruy at gmail dot com
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***************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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***************************************************************************
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"""
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__author__ = 'Alexander Bruy'
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__date__ = 'April 2015'
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__copyright__ = '(C) 2015, Alexander Bruy'
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# This will get replaced with a git SHA1 when you do a git archive
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__revision__ = '$Format:%H$'
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from qgis.core import (QgsApplication,
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QgsSpatialIndex,
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QgsFeatureRequest,
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QgsProcessingUtils)
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from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
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from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
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from processing.core.parameters import ParameterVector
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from processing.core.parameters import ParameterTableField
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from processing.core.parameters import ParameterNumber
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from processing.core.outputs import OutputVector
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class SelectByAttributeSum(QgisAlgorithm):
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INPUT = 'INPUT'
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FIELD = 'FIELD'
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VALUE = 'VALUE'
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OUTPUT = 'OUTPUT'
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def group(self):
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return self.tr('Vector selection tools')
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def __init__(self):
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super().__init__()
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def initAlgorithm(self, config=None):
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self.addParameter(ParameterVector(self.INPUT,
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self.tr('Input Layer')))
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self.addParameter(ParameterTableField(self.FIELD,
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self.tr('Selection attribute'),
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self.INPUT,
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ParameterTableField.DATA_TYPE_NUMBER))
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self.addParameter(ParameterNumber(self.VALUE, self.tr('Value')))
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self.addOutput(OutputVector(self.OUTPUT, self.tr('Selected (attribute sum)'), True))
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def name(self):
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return 'selectbyattributesum'
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def displayName(self):
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return self.tr('Select by attribute sum')
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def processAlgorithm(self, parameters, context, feedback):
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fileName = self.getParameterValue(self.INPUT)
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layer = QgsProcessingUtils.mapLayerFromString(fileName, context)
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fieldName = self.getParameterValue(self.FIELD)
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value = self.getParameterValue(self.VALUE)
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selected = layer.selectedFeatureIds()
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if len(selected) == 0:
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GeoAlgorithmExecutionException(
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self.tr('There is no selection in the input layer. '
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'Select one feature and try again.'))
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ft = layer.selectedFeatures()[0]
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geom = ft.geometry()
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attrSum = ft[fieldName]
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idx = QgsSpatialIndex(layer.getFeatures(QgsFeatureRequest.setSubsetOfAttributes([])))
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req = QgsFeatureRequest()
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completed = False
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while not completed:
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intersected = idx.intersects(geom.boundingBox())
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if len(intersected) < 0:
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feedback.pushInfo(self.tr('No adjacent features found.'))
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break
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req = QgsFeatureRequest().setFilterFids(intersected).setSubsetOfAttributes([fieldName], layer.fields())
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for ft in layer.getFeatures(req):
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tmpGeom = ft.geometry()
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if tmpGeom.touches(geom):
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geom = tmpGeom.combine(geom)
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selected.append(ft.id())
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attrSum += ft[fieldName]
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if attrSum >= value:
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completed = True
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break
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layer.selectByIds(selected)
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self.setOutputValue(self.OUTPUT, fileName)
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