[processing] added native raster calculator algorithm

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

Author: volaya

python/plugins/processing/algs/help/qgis.yaml

@@ -552,3 +552,18 @@ qgis:voronoipolygons: >
 
 qgis:zonalstatistics:
 
+qgis:rastercalculator: >
+    This algorithm allows to perform algebraic operations using raster layers.
+    
+    The resulting layer will have its values computed according to an expression. The expression can contain numerical values, operators and references to any of the layers in the current project. The following functions are also supported:
+    
+    - sin(), cos(), tan(), atan2(), ln(), log10()
+    
+    The extent and cellsize can be defined by the user. If the extent is not specified, the minimum extent that covers the input layers will be used. If the cellsize is not specified, the minimum cellsize of all input layers will be used.
+    
+    The cellsize is assumed to be the same in both X and Y axes.
+    
+    Layers are refered by their name as displayed in the layer list and the number of the band to use (based on 1), using the pattern 'layer_name@band number'. For instance, the first band from a layer named DEM will be referred as DEM@1.
+    
+    When using the calculator in the batch interface or from the console, the files to use have to be specified. The corresponding layers are refered using the base name of the file (without the full path). For instance, is using a layer at path/to/my/rasterfile.tif, the first band of that layer will be refered as rasterfile.tif@1.
+    

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

@@ -178,6 +178,7 @@
 from .GeometryByExpression import GeometryByExpression
 from .SnapGeometries import SnapGeometriesToLayer
 from .PoleOfInaccessibility import PoleOfInaccessibility
+from .RasterCalculator import RasterCalculator
 from .CreateAttributeIndex import CreateAttributeIndex
 from .DropGeometry import DropGeometry
 from .BasicStatistics import BasicStatisticsForField
@@ -245,7 +246,7 @@ def __init__(self):
                         RemoveNullGeometry(), ExtractByExpression(), ExtendLines(),
                         ExtractSpecificNodes(), GeometryByExpression(), SnapGeometriesToLayer(),
                         PoleOfInaccessibility(), CreateAttributeIndex(), DropGeometry(),
-                        BasicStatisticsForField()
+                        BasicStatisticsForField(), RasterCalculator()
                         ]
 
         if hasMatplotlib:

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

@@ -0,0 +1,164 @@
+# -*- coding: utf-8 -*-
+
+"""
+***************************************************************************
+    RasterLayerCalculator.py
+    ---------------------
+    Date                 : November 2016
+    Copyright            : (C) 2016 by Victor Olaya
+    Email                : volayaf 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.                                   *
+*                                                                         *
+***************************************************************************
+"""
+from processing.modeler.ModelerAlgorithm import ValueFromInput, ValueFromOutput
+import os
+
+
+__author__ = 'Victor Olaya'
+__date__ = 'November 2016'
+__copyright__ = '(C) 2016, Victor Olaya'
+
+# This will get replaced with a git SHA1 when you do a git archive
+
+__revision__ = '$Format:%H$'
+
+import math
+from processing.core.GeoAlgorithm import GeoAlgorithm
+from processing.core.parameters import ParameterMultipleInput, ParameterExtent, ParameterString, ParameterRaster, ParameterNumber
+from processing.core.outputs import OutputRaster
+from processing.tools import dataobjects
+from processing.algs.gdal.GdalUtils import GdalUtils
+from qgis.core import QgsRectangle
+from qgis.analysis import QgsRasterCalculator, QgsRasterCalculatorEntry
+from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
+from processing.algs.qgis.ui.RasterCalculatorWidgets import LayersListWidgetWrapper, ExpressionWidgetWrapper
+
+class RasterCalculator(GeoAlgorithm):
+
+    LAYERS = 'LAYERS'
+    EXTENT = 'EXTENT'
+    CELLSIZE = 'CELLSIZE'
+    EXPRESSION = 'EXPRESSION'
+    OUTPUT = 'OUTPUT'
+
+    def defineCharacteristics(self):
+        self.name, self.i18n_name = self.trAlgorithm('Raster calculator')
+        self.group, self.i18n_group = self.trAlgorithm('Raster')
+
+        self.addParameter(ParameterMultipleInput(self.LAYERS,
+                                          self.tr('Input layers'),
+                                          datatype=dataobjects.TYPE_RASTER,
+                                          optional=True,
+                                          metadata = {'widget_wrapper': LayersListWidgetWrapper}))
+        class ParameterExpression(ParameterString):
+            def evaluateForModeler(self, value, model): 
+                #print value                   
+                for i in list(model.inputs.values()):
+                    param = i.param
+                    if isinstance(param, ParameterRaster):
+                        new = "%s@" % os.path.basename(param.value)
+                        old = "%s@" % param.name
+                        value = value.replace(old, new)
+    
+                    for alg in list(model.algs.values()):
+                        for out in alg.algorithm.outputs:
+                            print out, out.value
+                            if isinstance(out, OutputRaster):
+                                if out.value:
+                                    new = "%s@" % os.path.basename(out.value)
+                                    old = "%s:%s@" % (alg.name, out.name)
+                                    value = value.replace(old, new)
+                return value
+
+        self.addParameter(ParameterExpression(self.EXPRESSION, self.tr('Expression'), 
+                                          multiline=True,
+                                          metadata = {'widget_wrapper': ExpressionWidgetWrapper}))
+        self.addParameter(ParameterNumber(self.CELLSIZE,
+                                          self.tr('Cellsize (use 0 or empty to set it automatically)'),
+                                          minValue=0.0, default=0.0, optional=True))
+        self.addParameter(ParameterExtent(self.EXTENT,
+                                          self.tr('Output extent'),
+                                          optional=True))        
+        self.addOutput(OutputRaster(self.OUTPUT, self.tr('Output')))
+
+
+    def processAlgorithm(self, progress):
+        expression = self.getParameterValue(self.EXPRESSION)
+        layersValue = self.getParameterValue(self.LAYERS)
+        layersDict = {}
+        if layersValue:
+            layers = [dataobjects.getObjectFromUri(f) for f in layersValue.split(";")]
+            layersDict = {os.path.basename(lyr.source()): lyr for lyr in layers}
+
+        for lyr in dataobjects.getRasterLayers():
+            name = lyr.name()
+            if (name + "@") in expression:
+                layersDict[name] = lyr
+
+        entries = []
+        for name, lyr in layersDict.iteritems():
+            for n in xrange(lyr.bandCount()):
+                entry = QgsRasterCalculatorEntry()
+                entry.ref = '%s@%i' % (name, n + 1)
+                entry.raster = lyr
+                entry.bandNumber = n + 1
+                entries.append(entry)
+
+        output = self.getOutputValue(self.OUTPUT)
+        extentValue = self.getParameterValue(self.EXTENT)
+
+        if extentValue:
+            extent = extentValue.split(',')
+            bbox = QgsRectangle(float(extent[0]), float(extent[2]),
+                                float(extent[1]), float(extent[3]))
+        else:
+            if layersDict:
+                bbox = layersDict.values()[0].extent()
+                for lyr in layersDict.values():
+                    bbox.combineExtentWith(lyr.extent())
+            else:
+                raise GeoAlgorithmExecutionException(self.tr("No layers selected"))
+        def _cellsize(layer):
+            return (layer.extent().xMaximum() - layer.extent().xMinimum()) / layer.width()
+        cellsize = self.getParameterValue(self.CELLSIZE) or min([_cellsize(lyr) for lyr in layersDict.values()])
+        width = math.floor((bbox.xMaximum() - bbox.xMinimum()) / cellsize)
+        height = math.floor((bbox.yMaximum() - bbox.yMinimum()) / cellsize)
+        driverName = GdalUtils.getFormatShortNameFromFilename(output)
+        calc = QgsRasterCalculator(expression,
+                                    output,
+                                    driverName,
+                                    bbox,
+                                    width,
+                                    height,
+                                    entries)
+
+        res = calc.processCalculation()
+        if res == QgsRasterCalculator.ParserError:
+            raise GeoAlgorithmExecutionException(self.tr("Error parsing formula"))
+
+    def processBeforeAddingToModeler(self, algorithm, model):
+        values = []
+        expression = algorithm.params[self.EXPRESSION]
+        for i in list(model.inputs.values()):
+            param = i.param
+            if isinstance(param, ParameterRaster) and "%s@" % param.name in expression:
+                values.append(ValueFromInput(param.name))
+
+        if algorithm.name:            
+            dependent = model.getDependentAlgorithms(algorithm.name)
+        else:
+            dependent = []
+        for alg in list(model.algs.values()):
+            if alg.name not in dependent:
+                for out in alg.algorithm.outputs:
+                    if (isinstance(out, OutputRaster) 
+                            and "%s:%s@" % (alg.name, out.name) in expression):
+                        values.append(ValueFromOutput(alg.name, out.name))
+
+        algorithm.params[self.LAYERS] = values