# -*- 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 qgis.PyQt.QtGui import QIcon
from qgis.core import QgsFeatureRequest
from qgis.analysis import QgsKernelDensityEstimation
from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
from processing.core.parameters import ParameterVector
from processing.core.parameters import ParameterNumber
from processing.core.parameters import ParameterSelection
from processing.core.parameters import ParameterTableField
from processing.core.outputs import OutputRaster
from processing.tools import dataobjects, vector, raster
from processing.algs.qgis.ui.HeatmapWidgets import HeatmapPixelSizeWidgetWrapper
pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
class Heatmap(GeoAlgorithm):
INPUT_LAYER = 'INPUT_LAYER'
RADIUS = 'RADIUS'
RADIUS_FIELD = 'RADIUS_FIELD'
WEIGHT_FIELD = 'WEIGHT_FIELD'
PIXEL_SIZE = 'PIXEL_SIZE'
KERNELS = ['Quartic',
'Triangular',
'Uniform',
'Triweight',
'Epanechnikov'
]
KERNEL = 'KERNEL'
DECAY = 'DECAY'
OUTPUT_VALUES = ['Raw',
'Scaled'
]
OUTPUT_VALUE = 'OUTPUT_VALUE'
OUTPUT_LAYER = 'OUTPUT_LAYER'
def getIcon(self):
return QIcon(os.path.join(pluginPath, 'images', 'heatmap.png'))
def defineCharacteristics(self):
self.name, self.i18n_name = self.trAlgorithm('Heatmap (Kernel Density Estimation)')
self.group, self.i18n_group = self.trAlgorithm('Interpolation')
self.tags = self.tr('heatmap,kde,hotspot')
self.addParameter(ParameterVector(self.INPUT_LAYER,
self.tr('Point layer'), [dataobjects.TYPE_VECTOR_POINT]))
self.addParameter(ParameterNumber(self.RADIUS,
self.tr('Radius (layer units)'),
0.0, 9999999999, 100.0))
radius_field_param = ParameterTableField(self.RADIUS_FIELD,
self.tr('Radius from field'), self.INPUT_LAYER, optional=True, datatype=ParameterTableField.DATA_TYPE_NUMBER)
radius_field_param.isAdvanced = True
self.addParameter(radius_field_param)
class ParameterHeatmapPixelSize(ParameterNumber):
def __init__(self, name='', description='', parent_layer=None, radius_param=None, radius_field_param=None, minValue=None, maxValue=None,
default=None, optional=False, metadata={}):
ParameterNumber.__init__(self, name, description, minValue, maxValue, default, optional, metadata)
self.parent_layer = parent_layer
self.radius_param = radius_param
self.radius_field_param = radius_field_param
self.addParameter(ParameterHeatmapPixelSize(self.PIXEL_SIZE,
self.tr('Output raster size'), parent_layer=self.INPUT_LAYER, radius_param=self.RADIUS,
radius_field_param=self.RADIUS_FIELD,
minValue=0.0, maxValue=9999999999, default=0.1,
metadata={'widget_wrapper': HeatmapPixelSizeWidgetWrapper}))
weight_field_param = ParameterTableField(self.WEIGHT_FIELD,
self.tr('Weight from field'), self.INPUT_LAYER, optional=True, datatype=ParameterTableField.DATA_TYPE_NUMBER)
weight_field_param.isAdvanced = True
self.addParameter(weight_field_param)
kernel_shape_param = ParameterSelection(self.KERNEL,
self.tr('Kernel shape'), self.KERNELS)
kernel_shape_param.isAdvanced = True
self.addParameter(kernel_shape_param)
decay_ratio = ParameterNumber(self.DECAY,
self.tr('Decay ratio (Triangular kernels only)'),
-100.0, 100.0, 0.0)
decay_ratio.isAdvanced = True
self.addParameter(decay_ratio)
output_scaling = ParameterSelection(self.OUTPUT_VALUE,
self.tr('Output value scaling'), self.OUTPUT_VALUES)
output_scaling.isAdvanced = True
self.addParameter(output_scaling)
self.addOutput(OutputRaster(self.OUTPUT_LAYER,
self.tr('Heatmap')))
def processAlgorithm(self, progress):
layer = dataobjects.getObjectFromUri(
self.getParameterValue(self.INPUT_LAYER))
radius = self.getParameterValue(self.RADIUS)
kernel_shape = self.getParameterValue(self.KERNEL)
pixel_size = self.getParameterValue(self.PIXEL_SIZE)
decay = self.getParameterValue(self.DECAY)
output_values = self.getParameterValue(self.OUTPUT_VALUE)
output = self.getOutputValue(self.OUTPUT_LAYER)
output_format = raster.formatShortNameFromFileName(output)
weight_field = self.getParameterValue(self.WEIGHT_FIELD)
radius_field = self.getParameterValue(self.RADIUS_FIELD)
attrs = []
kde_params = QgsKernelDensityEstimation.Parameters()
kde_params.vectorLayer = layer
kde_params.radius = radius
kde_params.pixelSize = pixel_size
# radius field
if radius_field:
kde_params.radiusField = radius_field
attrs.append(layer.fields().lookupField(radius_field))
# weight field
if weight_field:
kde_params.weightField = weight_field
attrs.append(layer.fields().lookupField(weight_field))
kde_params.shape = kernel_shape
kde_params.decayRatio = decay
kde_params.outputValues = output_values
kde = QgsKernelDensityEstimation(kde_params, output, output_format)
if kde.prepare() != QgsKernelDensityEstimation.Success:
raise GeoAlgorithmExecutionException(
self.tr('Could not create destination layer'))
request = QgsFeatureRequest()
request.setSubsetOfAttributes(attrs)
features = vector.features(layer, request)
total = 100.0 / len(features)
for current, f in enumerate(features):
if kde.addFeature(f) != QgsKernelDensityEstimation.Success:
raise GeoAlgorithmExecutionException(
self.tr('Error adding feature to heatmap'))
progress.setPercentage(int(current * total))
if kde.finalise() != QgsKernelDensityEstimation.Success:
raise GeoAlgorithmExecutionException(
self.tr('Could not save destination layer'))