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[FEATURE][processing] Port heatmap plugin to processing algorithm

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nyalldawson committed Dec 6, 2016
1 parent f212746 commit 83c38b0172546ab019f8fd7b08ea3e74434a60d9
@@ -0,0 +1,152 @@
# -*- 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 ParameterExtent
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

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))
self.addParameter(ParameterNumber(self.PIXEL_SIZE,
self.tr('Output pixel size (layer units)'),
0.0, 9999999999, 0.1))
self.addParameter(ParameterTableField(self.RADIUS_FIELD,
self.tr('Radius from field'), self.INPUT_LAYER, optional=True, datatype=ParameterTableField.DATA_TYPE_NUMBER))
self.addParameter(ParameterTableField(self.WEIGHT_FIELD,
self.tr('Weight from field'), self.INPUT_LAYER, optional=True, datatype=ParameterTableField.DATA_TYPE_NUMBER))
self.addParameter(ParameterSelection(self.KERNEL,
self.tr('Kernel shape'), self.KERNELS))
self.addParameter(ParameterNumber(self.DECAY,
self.tr('Decay ratio (Triangular kernels only)'),
-100.0, 100.0, 0.0))
self.addParameter(ParameterSelection(self.OUTPUT_VALUE,
self.tr('Output value scaling'), self.OUTPUT_VALUES))
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'))
@@ -36,6 +36,7 @@
)

from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
from processing.core.parameters import ParameterVector
from processing.core.parameters import ParameterSelection
from processing.core.parameters import ParameterNumber
@@ -182,6 +182,7 @@
from .CreateAttributeIndex import CreateAttributeIndex
from .DropGeometry import DropGeometry
from .BasicStatistics import BasicStatisticsForField
from .Heatmap import Heatmap

pluginPath = os.path.normpath(os.path.join(
os.path.split(os.path.dirname(__file__))[0], os.pardir))
@@ -246,7 +247,7 @@ def __init__(self):
RemoveNullGeometry(), ExtractByExpression(), ExtendLines(),
ExtractSpecificNodes(), GeometryByExpression(), SnapGeometriesToLayer(),
PoleOfInaccessibility(), CreateAttributeIndex(), DropGeometry(),
BasicStatisticsForField(), RasterCalculator()
BasicStatisticsForField(), RasterCalculator(), Heatmap()
]

if hasMatplotlib:
Binary file not shown.

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