QGIS/python/plugins/processing/algs/qgis/PointsInPolygonWeighted.py
Nyall Dawson 596b56c441 Faster PointsInPolygon(+Unique/Weighted) algorithms
- Avoid use of seperate feature requests for every point
- Use GEOS prepared geometries when testing for point containment

Quick stats:

~1500 point layer

BEFORE: 17 seconds
AFTER: 3 seconds

~900k point layer

BEFORE: 30 mins = canceled at 20%
AFTER: 2.5 mins = 100% complete
2015-11-13 13:24:08 +11:00

127 lines
5.2 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
PointsInPolygon.py
---------------------
Date : August 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. *
* *
***************************************************************************
"""
__author__ = 'Victor Olaya'
__date__ = 'August 2012'
__copyright__ = '(C) 2012, Victor Olaya'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'
from PyQt4.QtCore import QVariant
from qgis.core import QgsField, QgsFeatureRequest, QgsFeature, QgsGeometry
from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.parameters import ParameterVector
from processing.core.parameters import ParameterString
from processing.core.parameters import ParameterTableField
from processing.core.outputs import OutputVector
from processing.tools import dataobjects, vector
class PointsInPolygonWeighted(GeoAlgorithm):
POLYGONS = 'POLYGONS'
POINTS = 'POINTS'
OUTPUT = 'OUTPUT'
FIELD = 'FIELD'
WEIGHT = 'WEIGHT'
# =========================================================================
# def getIcon(self):
# return QIcon(os.path.dirname(__file__) + "/icons/sum_points.png")
# =========================================================================
def defineCharacteristics(self):
self.name, self.i18n_name = self.trAlgorithm('Count points in polygon(weighted)')
self.group, self.i18n_group = self.trAlgorithm('Vector analysis tools')
self.addParameter(ParameterVector(self.POLYGONS,
self.tr('Polygons'), [ParameterVector.VECTOR_TYPE_POLYGON]))
self.addParameter(ParameterVector(self.POINTS,
self.tr('Points'), [ParameterVector.VECTOR_TYPE_POINT]))
self.addParameter(ParameterTableField(self.WEIGHT,
self.tr('Weight field'), self.POINTS))
self.addParameter(ParameterString(self.FIELD,
self.tr('Count field name'), 'NUMPOINTS'))
self.addOutput(OutputVector(self.OUTPUT, self.tr('Weighted count')))
def processAlgorithm(self, progress):
polyLayer = dataobjects.getObjectFromUri(self.getParameterValue(self.POLYGONS))
pointLayer = dataobjects.getObjectFromUri(self.getParameterValue(self.POINTS))
fieldName = self.getParameterValue(self.FIELD)
fieldIdx = pointLayer.fieldNameIndex(self.getParameterValue(self.WEIGHT))
polyProvider = polyLayer.dataProvider()
fields = polyProvider.fields()
fields.append(QgsField(fieldName, QVariant.Int))
(idxCount, fieldList) = vector.findOrCreateField(polyLayer,
polyLayer.pendingFields(), fieldName)
writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(
fields.toList(), polyProvider.geometryType(), polyProvider.crs())
spatialIndex = vector.spatialindex(pointLayer)
ftPoint = QgsFeature()
outFeat = QgsFeature()
geom = QgsGeometry()
current = 0
features = vector.features(polyLayer)
total = 100.0 / float(len(features))
for ftPoly in features:
geom = ftPoly.geometry()
engine = QgsGeometry.createGeometryEngine(geom.geometry())
engine.prepareGeometry()
attrs = ftPoly.attributes()
count = 0
points = spatialIndex.intersects(geom.boundingBox())
if len(points) > 0:
progress.setText(unicode(len(points)))
request = QgsFeatureRequest().setFilterFids(points)
fit = pointLayer.getFeatures(request)
ftPoint = QgsFeature()
while fit.nextFeature(ftPoint):
tmpGeom = QgsGeometry(ftPoint.geometry())
if engine.contains(tmpGeom.geometry()):
weight = unicode(ftPoint.attributes()[fieldIdx])
try:
count += float(weight)
except:
# Ignore fields with non-numeric values
pass
outFeat.setGeometry(geom)
if idxCount == len(attrs):
attrs.append(count)
else:
attrs[idxCount] = count
outFeat.setAttributes(attrs)
writer.addFeature(outFeat)
current += 1
progress.setPercentage(int(current * total))
del writer