[processing] add Regular points algorithm (addresses #5953)

alexbruy · alexbruy · commit ae4a1441e94f · 2014-11-01T13:56:21.000+02:00
diff --git a/python/plugins/processing/algs/qgis/QGISAlgorithmProvider.py b/python/plugins/processing/algs/qgis/QGISAlgorithmProvider.py
@@ -31,6 +31,7 @@
 from PyQt4.QtGui import *
 
 from processing.core.AlgorithmProvider import AlgorithmProvider
+from ftools.RegularPoints import RegularPoints
 
 from RandomExtract import RandomExtract
 from RandomExtractWithinSubsets import RandomExtractWithinSubsets
@@ -145,7 +146,8 @@ def __init__(self):
                         RandomSelection(), RandomSelectionWithinSubsets(),
                         SelectByLocation(), RandomExtract(),
                         RandomExtractWithinSubsets(), ExtractByLocation(),
-                        SpatialJoin(), DeleteColumn(),
+                        SpatialJoin(), RegularPoints(),
+                        DeleteColumn(),
                         DeleteDuplicateGeometries(), TextToFloat(),
                         ExtractByAttribute(), SelectByAttribute(), Grid(),
                         Gridify(), HubDistance(), HubLines(), Merge(),
diff --git a/python/plugins/processing/algs/qgis/ftools/RegularPoints.py b/python/plugins/processing/algs/qgis/ftools/RegularPoints.py
@@ -0,0 +1,118 @@
+# -*- coding: utf-8 -*-
+
+"""
+***************************************************************************
+    RegularPoints.py
+    ---------------------
+    Date                 : September 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__ = 'September 2014'
+__copyright__ = '(C) 2014, Alexander Bruy'
+
+# This will get replaced with a git SHA1 when you do a git archive
+
+__revision__ = '$Format:%H$'
+
+from random import *
+
+from PyQt4.QtCore import *
+from qgis.core import *
+from qgis.utils import iface
+
+from processing.core.GeoAlgorithm import GeoAlgorithm
+from processing.core.parameters import ParameterExtent
+from processing.core.parameters import ParameterNumber
+from processing.core.parameters import ParameterBoolean
+from processing.core.outputs import OutputVector
+from processing.tools import vector
+
+
+class RegularPoints(GeoAlgorithm):
+
+    EXTENT = 'EXTENT'
+    SPACING = 'SPACING'
+    INSET = 'INSET'
+    RANDOMIZE = 'RANDOMIZE'
+    IS_SPACING = 'IS_SPACING'
+    OUTPUT = 'OUTPUT'
+
+    def defineCharacteristics(self):
+        self.name = 'Regular points'
+        self.group = 'Vector creation tools'
+
+        self.addParameter(ParameterExtent(self.EXTENT, 'Input extent'))
+        self.addParameter(ParameterNumber(self.SPACING,
+            'Point spacing/count', 0.0001, 999999999.999999999, 0.0001))
+        self.addParameter(ParameterNumber(self.INSET,
+            'Initial inset from corner (LH side)', 0.0, 9999.9999, 0.0))
+        self.addParameter(ParameterBoolean(self.RANDOMIZE,
+            'Apply random offset to point spacing', False))
+        self.addParameter(ParameterBoolean(self.IS_SPACING,
+            'Use point spacing', True))
+        self.addOutput(OutputVector(self.OUTPUT, 'Regular points'))
+
+    def processAlgorithm(self, progress):
+        extent = str(self.getParameterValue(self.EXTENT)).split(',')
+
+        spacing = float(self.getParameterValue(self.SPACING))
+        inset = float(self.getParameterValue(self.INSET))
+        randomize = self.getParameterValue(self.RANDOMIZE)
+        isSpacing = self.getParameterValue(self.IS_SPACING)
+
+        extent = QgsRectangle(float(extent[0]), float(extent[2]),
+                              float(extent[1]), float(extent[3]))
+
+        fields = QgsFields()
+        fields.append(QgsField('id', QVariant.Int, '', 10, 0))
+        mapCRS = iface.mapCanvas().mapSettings().destinationCrs()
+
+        writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(
+            fields, QGis.WKBPoint, mapCRS)
+
+        if randomize:
+            seed()
+
+        area = extent.width() * extent.height()
+        if isSpacing:
+            pSpacing = spacing
+        else:
+            pSpacing = sqrt(area / value)
+
+        f = QgsFeature()
+        f.initAttributes(1)
+        f.setFields(fields)
+
+        count = 0
+        total = 100.00 / (area / pSpacing)
+        y = extent.yMaximum() - inset
+        while y >= extent.yMinimum():
+            x = extent.xMinimum() + inset
+            while x <= extent.xMaximum():
+                if randomize:
+                    geom = QgsGeometry().fromPoint(QgsPoint(
+                        uniform(x - (pSpacing / 2.0), x + (pSpacing / 2.0)),
+                        uniform(y - (pSpacing / 2.0), y + (pSpacing / 2.0))))
+                else:
+                    geom = QgsGeometry().fromPoint(QgsPoint(x, y))
+
+                if geom.intersects(extent):
+                    f.setAttribute('id', count)
+                    f.setGeometry(geom)
+                    writer.addFeature(f)
+                    x += pSpacing
+                    count += 1
+                    progress.setPercentage(int(count* total))
+            y = y - pSpacing
+        del writer
