本文整理汇总了Python中qgis.analysis.QgsKernelDensityEstimation类的典型用法代码示例。如果您正苦于以下问题：Python QgsKernelDensityEstimation类的具体用法？Python QgsKernelDensityEstimation怎么用？Python QgsKernelDensityEstimation使用的例子？那么, 这里精选的类代码示例或许可以为您提供帮助。
在下文中一共展示了QgsKernelDensityEstimation类的2个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Python代码示例。
示例1: processAlgorithm
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}示例2: processAlgorithm
def processAlgorithm(self, parameters, context, feedback):
layer = QgsProcessingUtils.mapLayerFromString(self.getParameterValue(self.INPUT_LAYER), context)
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 = QgsProcessingUtils.getFeatures(layer, context, request)
total = 100.0 / QgsProcessingUtils.featureCount(layer, context)
for current, f in enumerate(features):
if kde.addFeature(f) != QgsKernelDensityEstimation.Success:
QgsMessageLog.logMessage(self.tr('Error adding feature with ID {} to heatmap').format(f.id()), self.tr('Processing'), QgsMessageLog.CRITICAL)
feedback.setProgress(int(current * total))
if kde.finalise() != QgsKernelDensityEstimation.Success:
raise GeoAlgorithmExecutionException(
self.tr('Could not save destination layer'))