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[processing] Add algorithm for reversing line directions

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nyalldawson committed Nov 18, 2015
1 parent 9009ef0 commit d0625b8b35c8b8315d89a9a43cd3b00a997d8fdd
@@ -132,6 +132,7 @@
from CheckValidity import CheckValidity
from OrientedMinimumBoundingBox import OrientedMinimumBoundingBox
from Smooth import Smooth
from ReverseLineDirection import ReverseLineDirection

pluginPath = os.path.normpath(os.path.join(
os.path.split(os.path.dirname(__file__))[0], os.pardir))
@@ -180,7 +181,8 @@ def __init__(self):
SelectByExpression(), HypsometricCurves(),
SplitLinesWithLines(), CreateConstantRaster(),
FieldsMapper(), SelectByAttributeSum(), Datasources2Vrt(),
CheckValidity(), OrientedMinimumBoundingBox(), Smooth()
CheckValidity(), OrientedMinimumBoundingBox(), Smooth(),
ReverseLineDirection()
]

if hasMatplotlib:
@@ -0,0 +1,84 @@
# -*- coding: utf-8 -*-

"""
***************************************************************************
ReverseLineDirection.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 ReverseLineDirection(GeoAlgorithm):

INPUT_LAYER = 'INPUT_LAYER'
OUTPUT_LAYER = 'OUTPUT_LAYER'

def defineCharacteristics(self):
self.name, self.i18n_name = self.trAlgorithm('Reverse line direction')
self.group, self.i18n_group = self.trAlgorithm('Vector geometry tools')

self.addParameter(ParameterVector(self.INPUT_LAYER,
self.tr('Input layer'), [ParameterVector.VECTOR_TYPE_LINE]))
self.addOutput(OutputVector(self.OUTPUT_LAYER, self.tr('Reversed')))

def processAlgorithm(self, progress):
layer = dataobjects.getObjectFromUri(
self.getParameterValue(self.INPUT_LAYER))
provider = layer.dataProvider()

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 = None
if inGeom and not inGeom.isEmpty():
reversedLine = inGeom.geometry().reversed()
if reversedLine is None:
raise GeoAlgorithmExecutionException(
self.tr('Error reversing line'))
outGeom = QgsGeometry(reversedLine)

outFeat.setGeometry(outGeom)
outFeat.setAttributes(attrs)
writer.addFeature(outFeat)
current += 1
progress.setPercentage(int(current * total))

del writer

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