[processing] expose zonal statistics from Zonal statistics plugin in toolbox

Author: alexbruy

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

@@ -167,6 +167,7 @@
 from .IdwInterpolationAttribute import IdwInterpolationAttribute
 from .TinInterpolationZValue import TinInterpolationZValue
 from .TinInterpolationAttribute import TinInterpolationAttribute
+from .ZonalStatisticsQgis import ZonalStatisticsQgis
 
 
 pluginPath = os.path.normpath(os.path.join(
@@ -225,9 +226,9 @@ def __init__(self):
                         OffsetLine(), PolygonCentroids(), Translate(),
                         SingleSidedBuffer(), PointsAlongGeometry(),
                         Aspect(), Slope(), Ruggedness(), Hillshade(),
-                        ReliefAuto(), IdwInterpolationZValue(),
-                        IdwInterpolationAttribute(), TinInterpolationZValue(),
-                        TinInterpolationAttribute()
+                        ReliefAuto(), ZonalStatisticsQgis(),
+                        IdwInterpolationZValue(), IdwInterpolationAttribute(),
+                        TinInterpolationZValue(), TinInterpolationAttribute()
                         ]
 
         if hasMatplotlib:

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

@@ -0,0 +1,102 @@
+# -*- coding: utf-8 -*-
+
+"""
+***************************************************************************
+    ZonalStatisticsQgis.py
+    ---------------------
+    Date                 : September 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__ = 'September 2016'
+__copyright__ = '(C) 2016, Alexander Bruy'
+
+# This will get replaced with a git SHA1 when you do a git archive
+
+__revision__ = '$Format:%H$'
+
+from qgis.analysis import QgsZonalStatistics
+
+from processing.core.GeoAlgorithm import GeoAlgorithm
+from processing.core.parameters import ParameterVector
+from processing.core.parameters import ParameterRaster
+from processing.core.parameters import ParameterString
+from processing.core.parameters import ParameterNumber
+from processing.core.parameters import ParameterSelection
+from processing.core.outputs import OutputVector
+from processing.tools import dataobjects
+
+
+class ZonalStatisticsQgis(GeoAlgorithm):
+
+    INPUT_RASTER = 'INPUT_RASTER'
+    RASTER_BAND = 'RASTER_BAND'
+    INPUT_VECTOR = 'INPUT_VECTOR'
+    COLUMN_PREFIX = 'COLUMN_PREFIX'
+    STATISTICS = 'STATS'
+    OUTPUT_LAYER = 'OUTPUT_LAYER'
+
+    def defineCharacteristics(self):
+        self.STATS = {self.tr('Count'): QgsZonalStatistics.Count,
+                      self.tr('Sum'): QgsZonalStatistics.Count,
+                      self.tr('Mean'): QgsZonalStatistics.Count,
+                      self.tr('Median'): QgsZonalStatistics.Count,
+                      self.tr('Std. dev.'): QgsZonalStatistics.Count,
+                      self.tr('Min'): QgsZonalStatistics.Count,
+                      self.tr('Max'): QgsZonalStatistics.Count,
+                      self.tr('Range'): QgsZonalStatistics.Count,
+                      self.tr('Minority'): QgsZonalStatistics.Count,
+                      self.tr('Majority'): QgsZonalStatistics.Count,
+                      self.tr('Variety'): QgsZonalStatistics.Count,
+                      self.tr('All'): QgsZonalStatistics.All
+                     }
+
+        self.name, self.i18n_name = self.trAlgorithm('Zonal Statistics (QGIS)')
+        self.group, self.i18n_group = self.trAlgorithm('Raster tools')
+
+        self.addParameter(ParameterRaster(self.INPUT_RASTER,
+                                          self.tr('Raster layer')))
+        self.addParameter(ParameterNumber(self.RASTER_BAND,
+                                          self.tr('Raster band'), 1, 999, 1))
+        self.addParameter(ParameterVector(self.INPUT_VECTOR,
+                                          self.tr('Vector layer containing zones'),
+                                          [dataobjects.TYPE_VECTOR_POLYGON]))
+        self.addParameter(ParameterString(self.COLUMN_PREFIX,
+                                          self.tr('Output column prefix'), '_'))
+        self.addParameter(ParameterSelection(self.STATISTICS,
+                                          self.tr('Statistics to calculate'),
+                                          list(self.STATS.keys()),
+                                          multiple=True))
+        self.addOutput(OutputVector(self.OUTPUT_LAYER,
+                                    self.tr('Zonal statistics'),
+                                    True,
+                                    datatype=[dataobjects.TYPE_VECTOR_POLYGON]))
+
+    def processAlgorithm(self, progress):
+        rasterPath = self.getParameterValue(self.INPUT_RASTER)
+        vectorPath = self.getParameterValue(self.INPUT_VECTOR)
+        bandNumber = self.getParameterValue(self.RASTER_BAND)
+        columnPrefix = self.getParameterValue(self.COLUMN_PREFIX)
+        st = self.getParameterValue(self.STATISTICS)
+
+        vectorLayer = dataobjects.getObjectFromUri(vectorPath)
+
+        keys = list(self.STATS.keys())
+        selectedStats = 0
+        for i in st:
+           selectedStats |= self.STATS[keys[i]]
+
+        zs = QgsZonalStatistics(vectorLayer, rasterPath, columnPrefix, bandNumber, selectedStats)
+        zs.calculateStatistics(None)
+
+        self.setOutputValue(self.OUTPUT_LAYER, vectorPath)