[processing] new tool: points to path

Work done for Faunalia funded by Prof. António Mira (University of Évora,
Portugal, Unidade de Biologia da Conservação) and Dr. Rosana Peixoto

Author: alexbruy

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

@@ -0,0 +1,121 @@
+# -*- coding: utf-8 -*-
+
+"""
+***************************************************************************
+    PointsToPaths.py
+    ---------------------
+    Date                 : April 2014
+    Copyright            : (C) 2014 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__ = 'April 2014'
+__copyright__ = '(C) 2014, Alexander Bruy'
+
+# This will get replaced with a git SHA1 when you do a git archive
+
+__revision__ = '$Format:%H$'
+
+from datetime import datetime
+from datetime import timedelta
+
+from PyQt4.QtCore import *
+
+from qgis.core import *
+
+from processing import interface
+from processing.core.GeoAlgorithm import GeoAlgorithm
+from processing.core.ProcessingLog import ProcessingLog
+from processing.parameters.ParameterVector import ParameterVector
+from processing.parameters.ParameterTableField import ParameterTableField
+from processing.parameters.ParameterString import ParameterString
+from processing.parameters.ParameterNumber import ParameterNumber
+from processing.outputs.OutputVector import OutputVector
+from processing.tools import dataobjects, vector
+
+class PointsToPaths(GeoAlgorithm):
+
+    VECTOR = 'VECTOR'
+    GROUP_FIELD = 'GROUP_FIELD'
+    ORDER_FIELD = 'ORDER_FIELD'
+    DATE_FORMAT = 'DATE_FORMAT'
+    GAP_PERIOD = 'GAP_PERIOD'
+    OUTPUT = 'OUTPUT'
+
+    def defineCharacteristics(self):
+        self.name = 'Points to path'
+        self.group = 'Vector creation tools'
+        self.addParameter(ParameterVector(self.VECTOR,
+            'Input point layer', [ParameterVector.VECTOR_TYPE_POINT]))
+        self.addParameter(
+            ParameterTableField(self.GROUP_FIELD, 'Group field', self.VECTOR))
+        self.addParameter(
+            ParameterTableField(self.ORDER_FIELD, 'Order field', self.VECTOR))
+        self.addParameter(ParameterString(self.DATE_FORMAT,
+            'Date format (if order field is DateTime)', '', optional=True))
+        self.addParameter(ParameterNumber(
+            self.GAP_PERIOD,
+            'Gap period (if order field is DateTime)', 0, 60, 0))
+        self.addOutput(OutputVector(self.OUTPUT, 'Paths'))
+
+    def processAlgorithm(self, progress):
+        layer = dataobjects.getObjectFromUri(
+            self.getParameterValue(self.VECTOR))
+        groupField = self.getParameterValue(self.GROUP_FIELD)
+        orderField = self.getParameterValue(self.ORDER_FIELD)
+        dateFormat = unicode(self.getParameterValue(self.DATE_FORMAT))
+        gap = int(self.getParameterValue(self.GAP_PERIOD))
+
+        fields = QgsFields()
+        fields.append(QgsField('group', QVariant.String, '', 254, 0))
+        fields.append(QgsField('begin', QVariant.String, '', 254, 0))
+        fields.append(QgsField('end', QVariant.String, '', 254, 0))
+        writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(
+            fields, QGis.WKBLineString, layer.dataProvider().crs())
+
+        points = dict()
+        features = vector.features(layer)
+        total = 100.0 / len(features)
+        for count, f in enumerate(features):
+            point = f.geometry().asPoint()
+            group = f[groupField]
+            order = f[orderField]
+            if dateFormat != '':
+                order = datetime.strptime(unicode(order), dateFormat)
+            if group in points:
+                points[group].append((order, point))
+            else:
+                points[group] = [(order, point)]
+
+            progress.setPercentage(int(count * total))
+
+        progress.setPercentage(0)
+
+        count = 0
+        total = 100.0 / len(points)
+        for k, v in points.iteritems():
+            v.sort()
+            f = QgsFeature()
+            f.initAttributes(len(fields))
+            f.setFields(fields)
+            f['group'] = k
+            f['begin'] = v[0][0]
+            f['end'] = v[-1][0]
+            line = []
+            for node in v:
+                line.append(node[1])
+            f.setGeometry(QgsGeometry.fromPolyline(line))
+            writer.addFeature(f)
+            count += 1
+            progress.setPercentage(int(count * total))
+
+        del writer

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

@@ -95,6 +95,7 @@
 from RandomPointsPolygonsFixed import RandomPointsPolygonsFixed
 from RandomPointsPolygonsVariable import RandomPointsPolygonsVariable
 from RandomPointsAlongLines import RandomPointsAlongLines
+from PointsToPaths import PointsToPaths
 
 # from VectorLayerHistogram import VectorLayerHistogram
 # from VectorLayerScatterplot import VectorLayerScatterplot
@@ -150,7 +151,7 @@ def __init__(self):
                         PointsFromLines(), RandomPointsExtent(),
                         RandomPointsLayer(), RandomPointsPolygonsFixed(),
                         RandomPointsPolygonsVariable(),
-                        RandomPointsAlongLines(),
+                        RandomPointsAlongLines(), PointsToPaths(),
                         # ------ raster ------
                         # CreateConstantRaster(),
                         # ------ graphics ------