# -*- coding: utf-8 -*-
"""
***************************************************************************
Heatmap.py
---------------------
Date : November 2016
Copyright : (C) 2016 by Nyall Dawson
Email : nyall dot dawson 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. *
* *
***************************************************************************
"""
__author__ = 'Nyall Dawson'
__date__ = 'November 2016'
__copyright__ = '(C) 2016, Nyall Dawson'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'
import os
from collections import OrderedDict
from qgis.PyQt.QtGui import QIcon
from qgis.core import (QgsApplication,
QgsFeatureRequest,
QgsRasterFileWriter,
QgsProcessing,
QgsProcessingException,
QgsProcessingParameterFeatureSource,
QgsProcessingParameterNumber,
QgsProcessingParameterDistance,
QgsProcessingParameterField,
QgsProcessingParameterEnum,
QgsProcessingParameterDefinition,
QgsProcessingParameterRasterDestination)
from qgis.analysis import QgsKernelDensityEstimation
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
class Heatmap(QgisAlgorithm):
INPUT = 'INPUT'
RADIUS = 'RADIUS'
RADIUS_FIELD = 'RADIUS_FIELD'
WEIGHT_FIELD = 'WEIGHT_FIELD'
PIXEL_SIZE = 'PIXEL_SIZE'
KERNEL = 'KERNEL'
DECAY = 'DECAY'
OUTPUT_VALUE = 'OUTPUT_VALUE'
OUTPUT = 'OUTPUT'
def icon(self):
return QgsApplication.getThemeIcon("/heatmap.svg")
def tags(self):
return self.tr('heatmap,kde,hotspot').split(',')
def group(self):
return self.tr('Interpolation')
def groupId(self):
return 'interpolation'
def name(self):
return 'heatmapkerneldensityestimation'
def displayName(self):
return self.tr('Heatmap (Kernel Density Estimation)')
def __init__(self):
super().__init__()
def initAlgorithm(self, config=None):
self.KERNELS = OrderedDict([(self.tr('Quartic'), QgsKernelDensityEstimation.KernelQuartic),
(self.tr('Triangular'), QgsKernelDensityEstimation.KernelTriangular),
(self.tr('Uniform'), QgsKernelDensityEstimation.KernelUniform),
(self.tr('Triweight'), QgsKernelDensityEstimation.KernelTriweight),
(self.tr('Epanechnikov'), QgsKernelDensityEstimation.KernelEpanechnikov)])
self.OUTPUT_VALUES = OrderedDict([(self.tr('Raw'), QgsKernelDensityEstimation.OutputRaw),
(self.tr('Scaled'), QgsKernelDensityEstimation.OutputScaled)])
self.addParameter(QgsProcessingParameterFeatureSource(self.INPUT,
self.tr('Point layer'),
[QgsProcessing.TypeVectorPoint]))
self.addParameter(QgsProcessingParameterDistance(self.RADIUS,
self.tr('Radius'),
100.0, self.INPUT, False, 0.0))
radius_field_param = QgsProcessingParameterField(self.RADIUS_FIELD,
self.tr('Radius from field'),
None,
self.INPUT,
QgsProcessingParameterField.Numeric,
optional=True
)
radius_field_param.setFlags(radius_field_param.flags() | QgsProcessingParameterDefinition.FlagAdvanced)
self.addParameter(radius_field_param)
class ParameterHeatmapPixelSize(QgsProcessingParameterNumber):
def __init__(self, name='', description='', parent_layer=None, radius_param=None, radius_field_param=None, minValue=None,
default=None, optional=False):
QgsProcessingParameterNumber.__init__(self, name, description, QgsProcessingParameterNumber.Double, default, optional, minValue)
self.parent_layer = parent_layer
self.radius_param = radius_param
self.radius_field_param = radius_field_param
def clone(self):
copy = ParameterHeatmapPixelSize(self.name(), self.description(), self.parent_layer, self.radius_param, self.radius_field_param, self.minimum(), self.maximum(), self.defaultValue((), self.flags() & QgsProcessingParameterDefinition.FlagOptional))
return copy
pixel_size_param = ParameterHeatmapPixelSize(self.PIXEL_SIZE,
self.tr('Output raster size'),
parent_layer=self.INPUT,
radius_param=self.RADIUS,
radius_field_param=self.RADIUS_FIELD,
minValue=0.0,
default=0.1)
pixel_size_param.setMetadata({
'widget_wrapper': {
'class': 'processing.algs.qgis.ui.HeatmapWidgets.HeatmapPixelSizeWidgetWrapper'}})
self.addParameter(pixel_size_param)
weight_field_param = QgsProcessingParameterField(self.WEIGHT_FIELD,
self.tr('Weight from field'),
None,
self.INPUT,
QgsProcessingParameterField.Numeric,
optional=True
)
weight_field_param.setFlags(weight_field_param.flags() | QgsProcessingParameterDefinition.FlagAdvanced)
self.addParameter(weight_field_param)
keys = list(self.KERNELS.keys())
kernel_shape_param = QgsProcessingParameterEnum(self.KERNEL,
self.tr('Kernel shape'),
keys,
allowMultiple=False,
defaultValue=0)
kernel_shape_param.setFlags(kernel_shape_param.flags() | QgsProcessingParameterDefinition.FlagAdvanced)
self.addParameter(kernel_shape_param)
decay_ratio = QgsProcessingParameterNumber(self.DECAY,
self.tr('Decay ratio (Triangular kernels only)'),
QgsProcessingParameterNumber.Double,
0.0, True, -100.0, 100.0)
decay_ratio.setFlags(decay_ratio.flags() | QgsProcessingParameterDefinition.FlagAdvanced)
self.addParameter(decay_ratio)
keys = list(self.OUTPUT_VALUES.keys())
output_scaling = QgsProcessingParameterEnum(self.OUTPUT_VALUE,
self.tr('Output value scaling'),
keys,
allowMultiple=False,
defaultValue=0)
output_scaling.setFlags(output_scaling.flags() | QgsProcessingParameterDefinition.FlagAdvanced)
self.addParameter(output_scaling)
self.addParameter(QgsProcessingParameterRasterDestination(self.OUTPUT, self.tr('Heatmap')))
def processAlgorithm(self, parameters, context, feedback):
source = self.parameterAsSource(parameters, self.INPUT, context)
if source is None:
raise QgsProcessingException(self.invalidSourceError(parameters, self.INPUT))
radius = self.parameterAsDouble(parameters, self.RADIUS, context)
kernel_shape = self.parameterAsEnum(parameters, self.KERNEL, context)
pixel_size = self.parameterAsDouble(parameters, self.PIXEL_SIZE, context)
decay = self.parameterAsDouble(parameters, self.DECAY, context)
output_values = self.parameterAsEnum(parameters, self.OUTPUT_VALUE, context)
outputFile = self.parameterAsOutputLayer(parameters, self.OUTPUT, context)
output_format = QgsRasterFileWriter.driverForExtension(os.path.splitext(outputFile)[1])
weight_field = self.parameterAsString(parameters, self.WEIGHT_FIELD, context)
radius_field = self.parameterAsString(parameters, self.RADIUS_FIELD, context)
attrs = []
kde_params = QgsKernelDensityEstimation.Parameters()
kde_params.source = source
kde_params.radius = radius
kde_params.pixelSize = pixel_size
# radius field
if radius_field:
kde_params.radiusField = radius_field
attrs.append(source.fields().lookupField(radius_field))
# weight field
if weight_field:
kde_params.weightField = weight_field
attrs.append(source.fields().lookupField(weight_field))
kde_params.shape = kernel_shape
kde_params.decayRatio = decay
kde_params.outputValues = output_values
kde = QgsKernelDensityEstimation(kde_params, outputFile, output_format)
if kde.prepare() != QgsKernelDensityEstimation.Success:
raise QgsProcessingException(
self.tr('Could not create destination layer'))
request = QgsFeatureRequest()
request.setSubsetOfAttributes(attrs)
features = source.getFeatures(request)
total = 100.0 / source.featureCount() if source.featureCount() else 0
for current, f in enumerate(features):
if feedback.isCanceled():
break
if kde.addFeature(f) != QgsKernelDensityEstimation.Success:
feedback.reportError(self.tr('Error adding feature with ID {} to heatmap').format(f.id()))
feedback.setProgress(int(current * total))
if kde.finalise() != QgsKernelDensityEstimation.Success:
raise QgsProcessingException(
self.tr('Could not save destination layer'))
return {self.OUTPUT: outputFile}