QGIS/python/plugins/processing/algs/qgis/PoleOfInaccessibility.py
Nyall Dawson 377b181c4e Port more processing dataobjects methods to c++
Also
- simplify and add tests
- remove large memory leak (persistant store of all non-project layers)
- remove broken support for direct loading postgres/virtual layers
by string (Python version was very broken and would never match
a postgres/virtual layer)
2017-04-05 19:50:46 +10:00

112 lines
4.1 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
PoleOfInaccessibility.py
------------------------
Date : November 2016
Copyright : (C) 2016 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 2016'
__copyright__ = '(C) 2016, Nyall Dawson'
# This will get replaced with a git SHA1 when you do a git archive323
__revision__ = '$Format:%H$'
import os
from qgis.core import QgsWkbTypes, QgsField, NULL
from qgis.PyQt.QtCore import QVariant
from qgis.PyQt.QtGui import QIcon
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
pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
class PoleOfInaccessibility(GeoAlgorithm):
INPUT_LAYER = 'INPUT_LAYER'
TOLERANCE = 'TOLERANCE'
OUTPUT_LAYER = 'OUTPUT_LAYER'
def icon(self):
return QIcon(os.path.join(pluginPath, 'images', 'ftools', 'centroids.png'))
def tags(self):
return self.tr('furthest,point,distant,extreme,maximum,centroid,center,centre').split(',')
def group(self):
return self.tr('Vector geometry tools')
def name(self):
return 'poleofinaccessibility'
def displayName(self):
return self.tr('Pole of Inaccessibility')
def defineCharacteristics(self):
self.addParameter(ParameterVector(self.INPUT_LAYER,
self.tr('Input layer'),
[dataobjects.TYPE_VECTOR_POLYGON]))
self.addParameter(ParameterNumber(self.TOLERANCE,
self.tr('Tolerance (layer units)'), default=1.0, minValue=0.0))
self.addOutput(OutputVector(self.OUTPUT_LAYER, self.tr('Point'), datatype=[dataobjects.TYPE_VECTOR_POINT]))
def processAlgorithm(self, feedback):
layer = dataobjects.getLayerFromString(
self.getParameterValue(self.INPUT_LAYER))
tolerance = self.getParameterValue(self.TOLERANCE)
fields = layer.fields()
fields.append(QgsField('dist_pole', QVariant.Double))
writer = self.getOutputFromName(
self.OUTPUT_LAYER).getVectorWriter(
fields,
QgsWkbTypes.Point,
layer.crs())
features = vector.features(layer)
total = 100.0 / len(features)
for current, input_feature in enumerate(features):
output_feature = input_feature
input_geometry = input_feature.geometry()
if input_geometry:
output_geometry, distance = input_geometry.poleOfInaccessibility(tolerance)
if not output_geometry:
raise GeoAlgorithmExecutionException(
self.tr('Error calculating pole of inaccessibility'))
attrs = input_feature.attributes()
attrs.append(distance)
output_feature.setAttributes(attrs)
output_feature.setGeometry(output_geometry)
else:
attrs = input_feature.attributes()
attrs.append(NULL)
output_feature.setAttributes(attrs)
writer.addFeature(output_feature)
feedback.setProgress(int(current * total))
del writer