[processing] add shortest path algorithm to Processing

python/plugins/processing/algs/qgis/ShortestPath.py

@@ -0,0 +1,120 @@
+# -*- coding: utf-8 -*-
+
+"""
+***************************************************************************
+    ShortestPath.py
+    ---------------------
+    Date                 : November 2016
+    Copyright            : (C) 2016 by Alexander Bruy
+    Email                : alexander dot bruy 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__ = 'Alexander Bruy'
+__date__ = 'November 2016'
+__copyright__ = '(C) 2016, Alexander Bruy'
+
+# 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.analysis import (QgsLineVectorLayerDirector,
+                           QgsDistanceArcProperter,
+                           QgsGraphBuilder,
+                           QgsGraphAnalyzer
+                          )
+
+from processing.core.GeoAlgorithm import GeoAlgorithm
+from processing.core.parameters import (ParameterVector,
+                                        ParameterPoint,
+                                        ParameterNumber,
+                                        ParameterString,
+                                        ParameterTableField,
+                                        ParameterSelection
+                                       )
+from processing.core.outputs import (OutputNumber,
+                                     OutputVector
+                                    )
+from processing.tools import dataobjects
+
+pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
+
+
+class ShortestPath(GeoAlgorithm):
+
+    INPUT_VECTOR = 'INPUT_VECTOR'
+    START_POINT = 'START_POINT'
+    END_POINT = 'END_POINT'
+    DIRECTION_FIELD = 'DIRECTION_FIELD'
+    VALUE_DIRECT = 'VALUE_DIRECT'
+    VALUE_REVERSED = 'VALUE_REVERSED'
+    VALUE_BIDIRECTIONAL = 'VALUE_BIDIRECTIONAL'
+    DEFAULT_DIRECTION = 'DEFAULT_DIRECTION'
+    PATH_LENGTH = 'PATH_LENGTH'
+    OUTPUT_LAYER = 'OUTPUT_LAYER'
+
+    def getIcon(self):
+        return QIcon(os.path.join(pluginPath, 'images', 'networkanalysis.png'))
+
+    def defineCharacteristics(self):
+        self.DIRECTIONS = {1: self.tr('Direct direction'),
+                           2: self.tr('Inverse direction'),
+                           3: self.tr('Bidirectional')
+                          }
+
+        self.UNITS = {0: self.tr('Meters'),
+                      1: self.tr('Kilometers')
+                     }
+
+        self.name, self.i18n_name = self.trAlgorithm('Shortest path')
+        self.group, self.i18n_group = self.trAlgorithm('Network analysis')
+
+        self.addParameter(ParameterVector(self.INPUT_VECTOR,
+                                          self.tr('Vector layer representing road network'),
+                                          [dataobjects.TYPE_VECTOR_LINE]))
+        self.addParameter(ParameterPoint(self.START_POINT,
+                                          self.tr('Start point')))
+        self.addParameter(ParameterPoint(self.END_POINT,
+                                          self.tr('End point')))
+
+        self.addParameter(ParameterTableField(self.DIRECTION_FIELD,
+                                              self.tr('Road direction field'),
+                                              self.INPUT_VECTOR))
+        self.addParameter(ParameterString(self.VALUE_DIRECT,
+                                          self.tr('Value for direct direction road'),
+                                          ''))
+        self.addParameter(ParameterString(self.VALUE_REVERSED,
+                                          self.tr('Value for reversed direction road'),
+                                          ''))
+        self.addParameter(ParameterString(self.VALUE_BIDIRECTIONAL,
+                                          self.tr('Value for bidirectional road'),
+                                          ''))
+        self.addParameter(ParameterSelection(self.DEFAULT_DIRECTION,
+                                          self.tr('Default road direction'),
+                                          list(self.DIRECTIONS.keys())))
+
+        self.addOutput(OutputNumber(self.PATH_LENGTH,
+                                    self.tr('Path length')))
+        self.addOutput(OutputVector(self.OUTPUT_LAYER,
+                                    self.tr('Shortest path'),
+                                    datatype=[dataobjects.TYPE_VECTOR_LINE]))
+
+    def processAlgorithm(self, progress):
+        layer = dataobjects.getObjectFromUri(
+                self.getParameterValue(self.INPUT_VECTOR))
+        fielName = self.getParameterValue(self.RASTER_BAND)
+        columnPrefix = self.getParameterValue(self.COLUMN_PREFIX)
+        st = self.getParameterValue(self.STATISTICS)
+
+        vectorLayer = dataobjects.getObjectFromUri(vectorPath)