QGIS/python/plugins/processing/algs/qgis/StatisticsByCategories.py
Nyall Dawson be88da8173 [FEATURE][processing] Add 'Join by location (summary)' algorithm
Like the main Join Attributes by Location algorithm, this algorithm
takes two layers and combines the attributes based on a spatial
criteria.

However this algorithm calculates summaries for the attributes for
all matching features, e.g. calculating the mean/min/max/etc.

The list of fields to summaries, and the summaries to
calculate for those, can be selected.
2017-09-13 18:45:56 +10:00

296 lines
12 KiB
Python
Executable File

# -*- coding: utf-8 -*-
"""
***************************************************************************
StatisticsByCategories.py
---------------------
Date : September 2012
Copyright : (C) 2012 by Victor Olaya
Email : volayaf 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. *
* *
***************************************************************************
"""
from builtins import str
__author__ = 'Victor Olaya'
__date__ = 'September 2012'
__copyright__ = '(C) 2012, Victor Olaya'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'
from qgis.core import (QgsProcessingParameterFeatureSource,
QgsStatisticalSummary,
QgsDateTimeStatisticalSummary,
QgsStringStatisticalSummary,
QgsFeatureRequest,
QgsProcessingParameterField,
QgsProcessingParameterFeatureSink,
QgsFields,
QgsField,
QgsWkbTypes,
QgsCoordinateReferenceSystem,
QgsFeature,
QgsFeatureSink,
QgsProcessing,
NULL)
from qgis.PyQt.QtCore import QVariant
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
from collections import defaultdict
class StatisticsByCategories(QgisAlgorithm):
INPUT = 'INPUT'
VALUES_FIELD_NAME = 'VALUES_FIELD_NAME'
CATEGORIES_FIELD_NAME = 'CATEGORIES_FIELD_NAME'
OUTPUT = 'OUTPUT'
def group(self):
return self.tr('Vector analysis')
def __init__(self):
super().__init__()
def initAlgorithm(self, config=None):
self.addParameter(QgsProcessingParameterFeatureSource(self.INPUT,
self.tr('Input vector layer'),
types=[QgsProcessing.TypeVector]))
self.addParameter(QgsProcessingParameterField(self.VALUES_FIELD_NAME,
self.tr(
'Field to calculate statistics on (if empty, only count is calculated)'),
parentLayerParameterName=self.INPUT, optional=True))
self.addParameter(QgsProcessingParameterField(self.CATEGORIES_FIELD_NAME,
self.tr('Field(s) with categories'),
parentLayerParameterName=self.INPUT,
type=QgsProcessingParameterField.Any, allowMultiple=True))
self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT, self.tr('Statistics by category')))
def name(self):
return 'statisticsbycategories'
def displayName(self):
return self.tr('Statistics by categories')
def processAlgorithm(self, parameters, context, feedback):
source = self.parameterAsSource(parameters, self.INPUT, context)
value_field_name = self.parameterAsString(parameters, self.VALUES_FIELD_NAME, context)
category_field_names = self.parameterAsFields(parameters, self.CATEGORIES_FIELD_NAME, context)
value_field_index = source.fields().lookupField(value_field_name)
if value_field_index >= 0:
value_field = source.fields().at(value_field_index)
else:
value_field = None
category_field_indexes = [source.fields().lookupField(n) for n in category_field_names]
# generate output fields
fields = QgsFields()
for c in category_field_indexes:
fields.append(source.fields().at(c))
def addField(name):
"""
Adds a field to the output, keeping the same data type as the value_field
"""
field = QgsField(value_field)
field.setName(name)
fields.append(field)
if value_field is None:
field_type = 'none'
fields.append(QgsField('count', QVariant.Int))
elif value_field.isNumeric():
field_type = 'numeric'
fields.append(QgsField('count', QVariant.Int))
fields.append(QgsField('unique', QVariant.Int))
fields.append(QgsField('min', QVariant.Double))
fields.append(QgsField('max', QVariant.Double))
fields.append(QgsField('range', QVariant.Double))
fields.append(QgsField('sum', QVariant.Double))
fields.append(QgsField('mean', QVariant.Double))
fields.append(QgsField('median', QVariant.Double))
fields.append(QgsField('stddev', QVariant.Double))
fields.append(QgsField('minority', QVariant.Double))
fields.append(QgsField('majority', QVariant.Double))
fields.append(QgsField('q1', QVariant.Double))
fields.append(QgsField('q3', QVariant.Double))
fields.append(QgsField('iqr', QVariant.Double))
elif value_field.type() in (QVariant.Date, QVariant.Time, QVariant.DateTime):
field_type = 'datetime'
fields.append(QgsField('count', QVariant.Int))
fields.append(QgsField('unique', QVariant.Int))
fields.append(QgsField('empty', QVariant.Int))
fields.append(QgsField('filled', QVariant.Int))
# keep same data type for these fields
addField('min')
addField('max')
else:
field_type = 'string'
fields.append(QgsField('count', QVariant.Int))
fields.append(QgsField('unique', QVariant.Int))
fields.append(QgsField('empty', QVariant.Int))
fields.append(QgsField('filled', QVariant.Int))
# keep same data type for these fields
addField('min')
addField('max')
fields.append(QgsField('min_length', QVariant.Int))
fields.append(QgsField('max_length', QVariant.Int))
fields.append(QgsField('mean_length', QVariant.Double))
request = QgsFeatureRequest().setFlags(QgsFeatureRequest.NoGeometry)
if value_field is not None:
attrs = [value_field_index]
else:
attrs = []
attrs.extend(category_field_indexes)
request.setSubsetOfAttributes(attrs)
features = source.getFeatures(request)
total = 50.0 / source.featureCount() if source.featureCount() else 0
if field_type == 'none':
values = defaultdict(lambda: 0)
else:
values = defaultdict(list)
for current, feat in enumerate(features):
if feedback.isCanceled():
break
feedback.setProgress(int(current * total))
attrs = feat.attributes()
cat = tuple([attrs[c] for c in category_field_indexes])
if field_type == 'none':
values[cat] += 1
continue
if field_type == 'numeric':
if attrs[value_field_index] == NULL:
continue
else:
value = float(attrs[value_field_index])
elif field_type == 'string':
if attrs[value_field_index] == NULL:
value = ''
else:
value = str(attrs[value_field_index])
elif attrs[value_field_index] == NULL:
value = NULL
else:
value = attrs[value_field_index]
values[cat].append(value)
(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
fields, QgsWkbTypes.NoGeometry, QgsCoordinateReferenceSystem())
if field_type == 'none':
self.saveCounts(values, sink, feedback)
elif field_type == 'numeric':
self.calcNumericStats(values, sink, feedback)
elif field_type == 'datetime':
self.calcDateTimeStats(values, sink, feedback)
else:
self.calcStringStats(values, sink, feedback)
return {self.OUTPUT: dest_id}
def saveCounts(self, values, sink, feedback):
total = 50.0 / len(values) if values else 0
current = 0
for cat, v in values.items():
if feedback.isCanceled():
break
feedback.setProgress(int(current * total) + 50)
f = QgsFeature()
f.setAttributes(list(cat) + [v])
sink.addFeature(f, QgsFeatureSink.FastInsert)
current += 1
def calcNumericStats(self, values, sink, feedback):
stat = QgsStatisticalSummary()
total = 50.0 / len(values) if values else 0
current = 0
for cat, v in values.items():
if feedback.isCanceled():
break
feedback.setProgress(int(current * total) + 50)
stat.calculate(v)
f = QgsFeature()
f.setAttributes(list(cat) + [stat.count(),
stat.variety(),
stat.min(),
stat.max(),
stat.range(),
stat.sum(),
stat.mean(),
stat.median(),
stat.stDev(),
stat.minority(),
stat.majority(),
stat.firstQuartile(),
stat.thirdQuartile(),
stat.interQuartileRange()])
sink.addFeature(f, QgsFeatureSink.FastInsert)
current += 1
def calcDateTimeStats(self, values, sink, feedback):
stat = QgsDateTimeStatisticalSummary()
total = 50.0 / len(values) if values else 0
current = 0
for cat, v in values.items():
if feedback.isCanceled():
break
feedback.setProgress(int(current * total) + 50)
stat.calculate(v)
f = QgsFeature()
f.setAttributes(list(cat) + [stat.count(),
stat.countDistinct(),
stat.countMissing(),
stat.count() - stat.countMissing(),
stat.statistic(QgsDateTimeStatisticalSummary.Min),
stat.statistic(QgsDateTimeStatisticalSummary.Max)
])
sink.addFeature(f, QgsFeatureSink.FastInsert)
current += 1
def calcStringStats(self, values, sink, feedback):
stat = QgsStringStatisticalSummary()
total = 50.0 / len(values) if values else 0
current = 0
for cat, v in values.items():
if feedback.isCanceled():
break
feedback.setProgress(int(current * total) + 50)
stat.calculate(v)
f = QgsFeature()
f.setAttributes(list(cat) + [stat.count(),
stat.countDistinct(),
stat.countMissing(),
stat.count() - stat.countMissing(),
stat.min(),
stat.max(),
stat.minLength(),
stat.maxLength(),
stat.meanLength()
])
sink.addFeature(f, QgsFeatureSink.FastInsert)
current += 1