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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.
189 lines
8.5 KiB
Python
189 lines
8.5 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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Heatmap.py
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---------------------
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Date : November 2016
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Copyright : (C) 2016 by Nyall Dawson
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Email : nyall dot dawson 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__ = 'Nyall Dawson'
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__date__ = 'November 2016'
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__copyright__ = '(C) 2016, Nyall Dawson'
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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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import os
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from qgis.PyQt.QtGui import QIcon
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from qgis.core import (QgsFeatureRequest,
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QgsMessageLog,
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QgsProcessingUtils,
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QgsProcessingParameterDefinition)
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from qgis.analysis import QgsKernelDensityEstimation
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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 ParameterNumber
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from processing.core.parameters import ParameterSelection
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from processing.core.parameters import ParameterTableField
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from processing.core.outputs import OutputRaster
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from processing.tools import dataobjects, raster
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from processing.algs.qgis.ui.HeatmapWidgets import HeatmapPixelSizeWidgetWrapper
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pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
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class Heatmap(QgisAlgorithm):
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INPUT_LAYER = 'INPUT_LAYER'
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RADIUS = 'RADIUS'
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RADIUS_FIELD = 'RADIUS_FIELD'
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WEIGHT_FIELD = 'WEIGHT_FIELD'
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PIXEL_SIZE = 'PIXEL_SIZE'
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KERNELS = ['Quartic',
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'Triangular',
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'Uniform',
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'Triweight',
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'Epanechnikov'
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]
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KERNEL = 'KERNEL'
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DECAY = 'DECAY'
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OUTPUT_VALUES = ['Raw',
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'Scaled'
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]
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OUTPUT_VALUE = 'OUTPUT_VALUE'
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OUTPUT_LAYER = 'OUTPUT_LAYER'
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def icon(self):
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return QIcon(os.path.join(pluginPath, 'images', 'heatmap.png'))
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def tags(self):
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return self.tr('heatmap,kde,hotspot').split(',')
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def group(self):
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return self.tr('Interpolation')
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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_LAYER,
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self.tr('Point layer'), [dataobjects.TYPE_VECTOR_POINT]))
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self.addParameter(ParameterNumber(self.RADIUS,
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self.tr('Radius (layer units)'),
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0.0, 9999999999, 100.0))
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radius_field_param = ParameterTableField(self.RADIUS_FIELD,
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self.tr('Radius from field'), self.INPUT_LAYER, optional=True, datatype=ParameterTableField.DATA_TYPE_NUMBER)
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radius_field_param.setFlags(radius_field_param.flags() | QgsProcessingParameterDefinition.FlagAdvanced)
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self.addParameter(radius_field_param)
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class ParameterHeatmapPixelSize(ParameterNumber):
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def __init__(self, name='', description='', parent_layer=None, radius_param=None, radius_field_param=None, minValue=None, maxValue=None,
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default=None, optional=False, metadata={}):
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ParameterNumber.__init__(self, name, description, minValue, maxValue, default, optional, metadata)
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self.parent_layer = parent_layer
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self.radius_param = radius_param
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self.radius_field_param = radius_field_param
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self.addParameter(ParameterHeatmapPixelSize(self.PIXEL_SIZE,
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self.tr('Output raster size'), parent_layer=self.INPUT_LAYER, radius_param=self.RADIUS,
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radius_field_param=self.RADIUS_FIELD,
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minValue=0.0, maxValue=9999999999, default=0.1,
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metadata={'widget_wrapper': HeatmapPixelSizeWidgetWrapper}))
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weight_field_param = ParameterTableField(self.WEIGHT_FIELD,
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self.tr('Weight from field'), self.INPUT_LAYER, optional=True, datatype=ParameterTableField.DATA_TYPE_NUMBER)
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weight_field_param.setFlags(weight_field_param.flags() | QgsProcessingParameterDefinition.FlagAdvanced)
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self.addParameter(weight_field_param)
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kernel_shape_param = ParameterSelection(self.KERNEL,
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self.tr('Kernel shape'), self.KERNELS)
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kernel_shape_param.setFlags(kernel_shape_param.flags() | QgsProcessingParameterDefinition.FlagAdvanced)
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self.addParameter(kernel_shape_param)
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decay_ratio = ParameterNumber(self.DECAY,
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self.tr('Decay ratio (Triangular kernels only)'),
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-100.0, 100.0, 0.0)
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decay_ratio.setFlags(decay_ratio.flags() | QgsProcessingParameterDefinition.FlagAdvanced)
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self.addParameter(decay_ratio)
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output_scaling = ParameterSelection(self.OUTPUT_VALUE,
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self.tr('Output value scaling'), self.OUTPUT_VALUES)
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output_scaling.setFlags(output_scaling.flags() | QgsProcessingParameterDefinition.FlagAdvanced)
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self.addParameter(output_scaling)
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self.addOutput(OutputRaster(self.OUTPUT_LAYER,
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self.tr('Heatmap')))
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def name(self):
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return 'heatmapkerneldensityestimation'
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def displayName(self):
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return self.tr('Heatmap (Kernel Density Estimation)')
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def processAlgorithm(self, parameters, context, feedback):
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layer = QgsProcessingUtils.mapLayerFromString(self.getParameterValue(self.INPUT_LAYER), context)
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radius = self.getParameterValue(self.RADIUS)
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kernel_shape = self.getParameterValue(self.KERNEL)
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pixel_size = self.getParameterValue(self.PIXEL_SIZE)
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decay = self.getParameterValue(self.DECAY)
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output_values = self.getParameterValue(self.OUTPUT_VALUE)
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output = self.getOutputValue(self.OUTPUT_LAYER)
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output_format = raster.formatShortNameFromFileName(output)
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weight_field = self.getParameterValue(self.WEIGHT_FIELD)
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radius_field = self.getParameterValue(self.RADIUS_FIELD)
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attrs = []
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kde_params = QgsKernelDensityEstimation.Parameters()
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kde_params.vectorLayer = layer
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kde_params.radius = radius
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kde_params.pixelSize = pixel_size
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# radius field
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if radius_field:
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kde_params.radiusField = radius_field
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attrs.append(layer.fields().lookupField(radius_field))
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# weight field
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if weight_field:
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kde_params.weightField = weight_field
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attrs.append(layer.fields().lookupField(weight_field))
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kde_params.shape = kernel_shape
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kde_params.decayRatio = decay
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kde_params.outputValues = output_values
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kde = QgsKernelDensityEstimation(kde_params, output, output_format)
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if kde.prepare() != QgsKernelDensityEstimation.Success:
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raise GeoAlgorithmExecutionException(
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self.tr('Could not create destination layer'))
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request = QgsFeatureRequest()
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request.setSubsetOfAttributes(attrs)
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features = QgsProcessingUtils.getFeatures(layer, context, request)
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total = 100.0 / layer.featureCount() if layer.featureCount() else 0
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for current, f in enumerate(features):
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if kde.addFeature(f) != QgsKernelDensityEstimation.Success:
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QgsMessageLog.logMessage(self.tr('Error adding feature with ID {} to heatmap').format(f.id()), self.tr('Processing'), QgsMessageLog.CRITICAL)
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feedback.setProgress(int(current * total))
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if kde.finalise() != QgsKernelDensityEstimation.Success:
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raise GeoAlgorithmExecutionException(
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self.tr('Could not save destination layer'))
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