Nyall Dawson 9009ef0b26 [processing] Add smooth algorithm
Allows for smoothing line or polygon layers
2015-11-18 16:27:14 +11:00

90 lines
3.5 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
Smooth.py
---------
Date : November 2015
Copyright : (C) 2015 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 2015'
__copyright__ = '(C) 2015, Nyall Dawson'
# This will get replaced with a git SHA1 when you do a git archive323
__revision__ = '$Format:%H$'
from qgis.core import QGis, QgsGeometry, QgsFeature
from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
from processing.core.parameters import ParameterVector, ParameterNumber
from processing.core.outputs import OutputVector
from processing.tools import dataobjects, vector
class Smooth(GeoAlgorithm):
INPUT_LAYER = 'INPUT_LAYER'
OUTPUT_LAYER = 'OUTPUT_LAYER'
ITERATIONS = 'ITERATIONS'
OFFSET = 'OFFSET'
def defineCharacteristics(self):
self.name, self.i18n_name = self.trAlgorithm('Smooth geometry')
self.group, self.i18n_group = self.trAlgorithm('Vector geometry tools')
self.addParameter(ParameterVector(self.INPUT_LAYER,
self.tr('Input layer'), [ParameterVector.VECTOR_TYPE_POLYGON, ParameterVector.VECTOR_TYPE_LINE]))
self.addParameter(ParameterNumber(self.ITERATIONS,
self.tr('Iterations'), default=1, minValue=1, maxValue=10))
self.addParameter(ParameterNumber(self.OFFSET,
self.tr('Offset'), default=0.25, minValue=0.0, maxValue=0.5))
self.addOutput(OutputVector(self.OUTPUT_LAYER, self.tr('Smoothed')))
def processAlgorithm(self, progress):
layer = dataobjects.getObjectFromUri(
self.getParameterValue(self.INPUT_LAYER))
provider = layer.dataProvider()
iterations = self.getParameterValue(self.ITERATIONS)
offset = self.getParameterValue(self.OFFSET)
writer = self.getOutputFromName(
self.OUTPUT_LAYER).getVectorWriter(
layer.fields().toList(),
provider.geometryType(),
layer.crs())
outFeat = QgsFeature()
features = vector.features(layer)
total = 100.0 / float(len(features))
current = 0
for inFeat in features:
inGeom = inFeat.constGeometry()
attrs = inFeat.attributes()
outGeom = inGeom.smooth(iterations, offset)
if outGeom is None:
raise GeoAlgorithmExecutionException(
self.tr('Error smoothing geometry'))
outFeat.setGeometry(outGeom)
outFeat.setAttributes(attrs)
writer.addFeature(outFeat)
current += 1
progress.setPercentage(int(current * total))
del writer