# -*- coding: utf-8 -*-
"""
***************************************************************************
EliminateSelection.py
---------------------
Date : January 2017
Copyright : (C) 2017 by Bernhard Ströbl
Email : bernhard.stroebl@jena.de
***************************************************************************
* *
* 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__ = 'Bernhard Ströbl'
__date__ = 'January 2017'
__copyright__ = '(C) 2017, Bernhard Ströbl'
# 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 (QgsApplication,
QgsFeatureRequest,
QgsFeature,
QgsFeatureSink,
QgsGeometry,
QgsProcessingAlgorithm,
QgsProcessingException,
QgsProcessingUtils,
QgsProcessingParameterVectorLayer,
QgsProcessingParameterEnum,
QgsProcessing,
QgsProcessingParameterFeatureSink)
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
class EliminateSelection(QgisAlgorithm):
INPUT = 'INPUT'
OUTPUT = 'OUTPUT'
MODE = 'MODE'
MODE_LARGEST_AREA = 0
MODE_SMALLEST_AREA = 1
MODE_BOUNDARY = 2
def icon(self):
return QgsApplication.getThemeIcon("/algorithms/mAlgorithmDissolve.svg")
def svgIconPath(self):
return QgsApplication.iconPath("/algorithms/mAlgorithmDissolve.svg")
def group(self):
return self.tr('Vector geometry')
def groupId(self):
return 'vectorgeometry'
def __init__(self):
super().__init__()
def flags(self):
return super().flags() | QgsProcessingAlgorithm.FlagNoThreading
def initAlgorithm(self, config=None):
self.modes = [self.tr('Largest Area'),
self.tr('Smallest Area'),
self.tr('Largest Common Boundary')]
self.addParameter(QgsProcessingParameterVectorLayer(self.INPUT,
self.tr('Input layer'), [QgsProcessing.TypeVectorPolygon]))
self.addParameter(QgsProcessingParameterEnum(self.MODE,
self.tr('Merge selection with the neighbouring polygon with the'),
options=self.modes))
self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT, self.tr('Eliminated'), QgsProcessing.TypeVectorPolygon))
def name(self):
return 'eliminateselectedpolygons'
def displayName(self):
return self.tr('Eliminate selected polygons')
def processAlgorithm(self, parameters, context, feedback):
inLayer = self.parameterAsVectorLayer(parameters, self.INPUT, context)
boundary = self.parameterAsEnum(parameters, self.MODE, context) == self.MODE_BOUNDARY
smallestArea = self.parameterAsEnum(parameters, self.MODE, context) == self.MODE_SMALLEST_AREA
if inLayer.selectedFeatureCount() == 0:
feedback.reportError(self.tr('{0}: (No selection in input layer "{1}")').format(self.displayName(), parameters[self.INPUT]))
featToEliminate = []
selFeatIds = inLayer.selectedFeatureIds()
(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
inLayer.fields(), inLayer.wkbType(), inLayer.sourceCrs())
if sink is None:
raise QgsProcessingException(self.invalidSinkError(parameters, self.OUTPUT))
for aFeat in inLayer.getFeatures():
if feedback.isCanceled():
break
if aFeat.id() in selFeatIds:
# Keep references to the features to eliminate
featToEliminate.append(aFeat)
else:
# write the others to output
sink.addFeature(aFeat, QgsFeatureSink.FastInsert)
# Delete all features to eliminate in processLayer
processLayer = QgsProcessingUtils.mapLayerFromString(dest_id, context)
processLayer.startEditing()
# ANALYZE
if len(featToEliminate) > 0: # Prevent zero division
start = 20.00
add = 80.00 / len(featToEliminate)
else:
start = 100
feedback.setProgress(start)
madeProgress = True
# We go through the list and see if we find any polygons we can
# merge the selected with. If we have no success with some we
# merge and then restart the whole story.
while madeProgress: # Check if we made any progress
madeProgress = False
featNotEliminated = []
# Iterate over the polygons to eliminate
for i in range(len(featToEliminate)):
if feedback.isCanceled():
break
feat = featToEliminate.pop()
geom2Eliminate = feat.geometry()
bbox = geom2Eliminate.boundingBox()
fit = processLayer.getFeatures(
QgsFeatureRequest().setFilterRect(bbox).setSubsetOfAttributes([]))
mergeWithFid = None
mergeWithGeom = None
max = 0
min = -1
selFeat = QgsFeature()
# use prepared geometries for faster intersection tests
engine = QgsGeometry.createGeometryEngine(geom2Eliminate.constGet())
engine.prepareGeometry()
while fit.nextFeature(selFeat):
if feedback.isCanceled():
break
selGeom = selFeat.geometry()
if engine.intersects(selGeom.constGet()):
# We have a candidate
iGeom = geom2Eliminate.intersection(selGeom)
if not iGeom:
continue
if boundary:
selValue = iGeom.length()
else:
# area. We need a common boundary in
# order to merge
if 0 < iGeom.length():
selValue = selGeom.area()
else:
selValue = -1
if -1 != selValue:
useThis = True
if smallestArea:
if -1 == min:
min = selValue
else:
if selValue < min:
min = selValue
else:
useThis = False
else:
if selValue > max:
max = selValue
else:
useThis = False
if useThis:
mergeWithFid = selFeat.id()
mergeWithGeom = QgsGeometry(selGeom)
# End while fit
if mergeWithFid is not None:
# A successful candidate
newGeom = mergeWithGeom.combine(geom2Eliminate)
if processLayer.changeGeometry(mergeWithFid, newGeom):
madeProgress = True
else:
raise QgsProcessingException(
self.tr('Could not replace geometry of feature with id {0}').format(mergeWithFid))
start = start + add
feedback.setProgress(start)
else:
featNotEliminated.append(feat)
# End for featToEliminate
featToEliminate = featNotEliminated
# End while
if not processLayer.commitChanges():
raise QgsProcessingException(self.tr('Could not commit changes'))
for feature in featNotEliminated:
if feedback.isCanceled():
break
sink.addFeature(feature, QgsFeatureSink.FastInsert)
return {self.OUTPUT: dest_id}