QGIS/python/plugins/processing/algs/qgis/JoinAttributes.py
Nyall Dawson 1e13d733c2 Move declaration of algorithm parameters/outputs to a new virtual
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.
2017-07-10 16:31:14 +10:00

118 lines
4.7 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
JoinAttributes.py
---------------------
Date : August 2012
Copyright : (C) 2012 by Victor Olaya
Email : volayaf 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. *
* *
***************************************************************************
"""
from builtins import str
__author__ = 'Victor Olaya'
__date__ = 'August 2012'
__copyright__ = '(C) 2012, Victor Olaya'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'
import os
from qgis.core import (QgsFeature,
QgsFeatureSink,
QgsApplication,
QgsProcessingUtils)
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
from processing.core.parameters import ParameterVector
from processing.core.parameters import ParameterTable
from processing.core.parameters import ParameterTableField
from processing.core.outputs import OutputVector
from processing.tools import vector
pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
class JoinAttributes(QgisAlgorithm):
OUTPUT_LAYER = 'OUTPUT_LAYER'
INPUT_LAYER = 'INPUT_LAYER'
INPUT_LAYER_2 = 'INPUT_LAYER_2'
TABLE_FIELD = 'TABLE_FIELD'
TABLE_FIELD_2 = 'TABLE_FIELD_2'
def group(self):
return self.tr('Vector general tools')
def __init__(self):
super().__init__()
def initAlgorithm(self, config=None):
self.addParameter(ParameterVector(self.INPUT_LAYER,
self.tr('Input layer')))
self.addParameter(ParameterTable(self.INPUT_LAYER_2,
self.tr('Input layer 2'), False))
self.addParameter(ParameterTableField(self.TABLE_FIELD,
self.tr('Table field'), self.INPUT_LAYER))
self.addParameter(ParameterTableField(self.TABLE_FIELD_2,
self.tr('Table field 2'), self.INPUT_LAYER_2))
self.addOutput(OutputVector(self.OUTPUT_LAYER,
self.tr('Joined layer')))
def name(self):
return 'joinattributestable'
def displayName(self):
return self.tr('Join attributes table')
def processAlgorithm(self, parameters, context, feedback):
input = self.getParameterValue(self.INPUT_LAYER)
input2 = self.getParameterValue(self.INPUT_LAYER_2)
output = self.getOutputFromName(self.OUTPUT_LAYER)
field = self.getParameterValue(self.TABLE_FIELD)
field2 = self.getParameterValue(self.TABLE_FIELD_2)
layer = QgsProcessingUtils.mapLayerFromString(input, context)
joinField1Index = layer.fields().lookupField(field)
layer2 = QgsProcessingUtils.mapLayerFromString(input2, context)
joinField2Index = layer2.fields().lookupField(field2)
outFields = vector.combineVectorFields(layer, layer2)
writer = output.getVectorWriter(outFields, layer.wkbType(), layer.crs(), context)
# Cache attributes of Layer 2
cache = {}
features = QgsProcessingUtils.getFeatures(layer2, context)
total = 100.0 / layer2.featureCount() if layer2.featureCount() else 0
for current, feat in enumerate(features):
attrs = feat.attributes()
joinValue2 = str(attrs[joinField2Index])
if joinValue2 not in cache:
cache[joinValue2] = attrs
feedback.setProgress(int(current * total))
# Create output vector layer with additional attribute
outFeat = QgsFeature()
features = QgsProcessingUtils.getFeatures(layer, context)
total = 100.0 / layer.featureCount() if layer.featureCount() else 0
for current, feat in enumerate(features):
outFeat.setGeometry(feat.geometry())
attrs = feat.attributes()
joinValue1 = str(attrs[joinField1Index])
attrs.extend(cache.get(joinValue1, []))
outFeat.setAttributes(attrs)
writer.addFeature(outFeat, QgsFeatureSink.FastInsert)
feedback.setProgress(int(current * total))
del writer