diff --git a/python/plugins/processing/algs/gdal/GdalAlgorithm.py b/python/plugins/processing/algs/gdal/GdalAlgorithm.py
index 2591311685d..be93eb89518 100644
--- a/python/plugins/processing/algs/gdal/GdalAlgorithm.py
+++ b/python/plugins/processing/algs/gdal/GdalAlgorithm.py
@@ -95,10 +95,11 @@ class GdalAlgorithm(GeoAlgorithm):
                 '''.format(self.commandName(), url)
 
     def commandName(self):
+        parameters = {}
         for output in self.outputs:
             output.setValue("dummy")
-        for param in self.parameters:
-            param.setValue("1")
+        for param in self.parameterDefinitions():
+            parameters[param.name()] = "1"
         name = self.getConsoleCommands(parameters)[0]
         if name.endswith(".py"):
             name = name[:-3]
diff --git a/python/plugins/processing/algs/grass7/Grass7Algorithm.py b/python/plugins/processing/algs/grass7/Grass7Algorithm.py
index 95694080f20..ad757eb1867 100644
--- a/python/plugins/processing/algs/grass7/Grass7Algorithm.py
+++ b/python/plugins/processing/algs/grass7/Grass7Algorithm.py
@@ -132,11 +132,11 @@ class Grass7Algorithm(GeoAlgorithm):
                 lines = infile.readlines()
                 for i in range(len(lines)):
                     if lines[i].startswith('<DT><b>'):
-                        for param in self.parameters:
-                            searchLine = '<b>' + param.name + '</b>'
+                        for param in self.parameterDefinitions():
+                            searchLine = '<b>' + param.name() + '</b>'
                             if searchLine in lines[i]:
                                 i += 1
-                                descs[param.name] = (lines[i])[4:-6]
+                                descs[param.name()] = (lines[i])[4:-6]
                                 break
 
         except Exception:
@@ -217,14 +217,14 @@ class Grass7Algorithm(GeoAlgorithm):
             param.setFlags(param.flags() | QgsProcessingParameterDefinition.FlagAdvanced)
             self.addParameter(param)
 
-    def getDefaultCellsize(self):
-        context = dataobjects.createContext()
+    def getDefaultCellsize(self, parameters, context):
         cellsize = 0
-        for param in self.parameters:
-            if param.value:
+        for param in self.parameterDefinitions():
+            if param.name() in parameters:
+                value = parameters[param.name()]
                 if isinstance(param, ParameterRaster):
-                    if isinstance(param.value, QgsRasterLayer):
-                        layer = param.value
+                    if isinstance(value, QgsRasterLayer):
+                        layer = value
                     else:
                         layer = QgsProcessingUtils.mapLayerFromString(param.value, context)
                     cellsize = max(cellsize, (layer.extent().xMaximum() -
@@ -232,7 +232,7 @@ class Grass7Algorithm(GeoAlgorithm):
                                    layer.width())
                 elif isinstance(param, ParameterMultipleInput):
 
-                    layers = param.value.split(';')
+                    layers = value.split(';')
                     for layername in layers:
                         layer = QgsProcessingUtils.mapLayerFromString(layername, context)
                         if isinstance(layer, QgsRasterLayer):
@@ -274,7 +274,7 @@ class Grass7Algorithm(GeoAlgorithm):
                 func = getattr(self.module, 'processInputs')
                 func(self)
             else:
-                self.processInputs()
+                self.processInputs(parameters,context)
 
             if hasattr(self.module, 'processCommand'):
                 func = getattr(self.module, 'processCommand')
@@ -288,7 +288,7 @@ class Grass7Algorithm(GeoAlgorithm):
             else:
                 self.processOutputs()
         else:
-            self.processInputs()
+            self.processInputs(parameters,context)
             self.processCommand()
             self.processOutputs()
 
@@ -317,13 +317,13 @@ class Grass7Algorithm(GeoAlgorithm):
         else:
             Grass7Utils.endGrass7Session()
 
-    def processInputs(self):
+    def processInputs(self, parameters, context):
         """Prepare the GRASS import commands"""
-        for param in self.parameters:
+        for param in self.parameterDefinitions():
             if isinstance(param, ParameterRaster):
-                if param.value is None:
+                if not param.name() in parameters():
                     continue
-                value = param.value
+                value = parameters[param.name()]
 
                 # Check if the layer hasn't already been exported in, for
                 # example, previous GRASS calls in this session
@@ -333,9 +333,9 @@ class Grass7Algorithm(GeoAlgorithm):
                     self.setSessionProjectionFromLayer(value, self.commands)
                     self.commands.append(self.exportRasterLayer(value))
             if isinstance(param, ParameterVector):
-                if param.value is None:
+                if not param.name() in parameters():
                     continue
-                value = param.value
+                value = parameters[param.name()]
                 if value in list(self.exportedLayers.keys()):
                     continue
                 else:
@@ -344,9 +344,10 @@ class Grass7Algorithm(GeoAlgorithm):
             if isinstance(param, ParameterTable):
                 pass
             if isinstance(param, ParameterMultipleInput):
-                if param.value is None:
+                if not param.name() in parameters():
                     continue
-                layers = param.value.split(';')
+                value = parameters[param.name()]
+                layers = value.split(';')
                 if layers is None or len(layers) == 0:
                     continue
                 if param.datatype == dataobjects.TYPE_RASTER:
@@ -384,7 +385,7 @@ class Grass7Algorithm(GeoAlgorithm):
         if cellsize:
             command += ' res=' + str(cellsize)
         else:
-            command += ' res=' + str(self.getDefaultCellsize())
+            command += ' res=' + str(self.getDefaultCellsize(parameters, context))
         alignToResolution = \
             self.getParameterValue(self.GRASS_REGION_ALIGN_TO_RESOLUTION)
         if alignToResolution:
diff --git a/python/plugins/processing/algs/grass7/ext/i.py b/python/plugins/processing/algs/grass7/ext/i.py
index aeb56057190..cf4cef784c8 100644
--- a/python/plugins/processing/algs/grass7/ext/i.py
+++ b/python/plugins/processing/algs/grass7/ext/i.py
@@ -93,7 +93,7 @@ def orderedInput(alg, inputParameter, targetParameterDef, numSeq=None):
     if cellsize:
         command += ' res=' + str(cellsize)
     else:
-        command += ' res=' + str(alg.getDefaultCellsize())
+        command += ' res=' + str(alg.getDefaultCellsize(parameters, context))
     alignToResolution = \
         alg.getParameterValue(alg.GRASS_REGION_ALIGN_TO_RESOLUTION)
     if alignToResolution:
diff --git a/python/plugins/processing/algs/grass7/ext/r_blend_combine.py b/python/plugins/processing/algs/grass7/ext/r_blend_combine.py
index 39eb685d3b5..5f4e951149e 100644
--- a/python/plugins/processing/algs/grass7/ext/r_blend_combine.py
+++ b/python/plugins/processing/algs/grass7/ext/r_blend_combine.py
@@ -57,7 +57,7 @@ def processInputs(alg):
     if cellsize:
         command += ' res=' + str(cellsize)
     else:
-        command += ' res=' + str(alg.getDefaultCellsize())
+        command += ' res=' + str(alg.getDefaultCellsize(parameters, context))
     alignToResolution = alg.getParameterValue(alg.GRASS_REGION_ALIGN_TO_RESOLUTION)
     if alignToResolution:
         command += ' -a'
diff --git a/python/plugins/processing/algs/grass7/ext/r_blend_rgb.py b/python/plugins/processing/algs/grass7/ext/r_blend_rgb.py
index 98c1e4b069b..aec81a8c255 100644
--- a/python/plugins/processing/algs/grass7/ext/r_blend_rgb.py
+++ b/python/plugins/processing/algs/grass7/ext/r_blend_rgb.py
@@ -59,7 +59,7 @@ def processInputs(alg):
     if cellsize:
         command += ' res=' + str(cellsize)
     else:
-        command += ' res=' + str(alg.getDefaultCellsize())
+        command += ' res=' + str(alg.getDefaultCellsize(parameters, context))
     alignToResolution = alg.getParameterValue(alg.GRASS_REGION_ALIGN_TO_RESOLUTION)
     if alignToResolution:
         command += ' -a'
diff --git a/python/plugins/processing/algs/grass7/ext/r_category.py b/python/plugins/processing/algs/grass7/ext/r_category.py
index 538250353d1..04b67143812 100644
--- a/python/plugins/processing/algs/grass7/ext/r_category.py
+++ b/python/plugins/processing/algs/grass7/ext/r_category.py
@@ -75,13 +75,13 @@ def processInputs(alg):
         if cellsize:
             command += ' res=' + str(cellsize)
         else:
-            command += ' res=' + str(alg.getDefaultCellsize())
+            command += ' res=' + str(alg.getDefaultCellsize(parameters, context))
         alignToResolution = alg.getParameterValue(alg.GRASS_REGION_ALIGN_TO_RESOLUTION)
         if alignToResolution:
             command += ' -a'
         alg.commands.append(command)
     else:
-        alg.processInputs()
+        alg.processInputs(context, parameters)
 
 
 def processCommand(alg, parameters):
diff --git a/python/plugins/processing/algs/grass7/ext/r_colors.py b/python/plugins/processing/algs/grass7/ext/r_colors.py
index 64ed1d67e94..ad73c812a00 100644
--- a/python/plugins/processing/algs/grass7/ext/r_colors.py
+++ b/python/plugins/processing/algs/grass7/ext/r_colors.py
@@ -65,7 +65,7 @@ def processInputs(alg):
     if cellsize:
         command += ' res=' + str(cellsize)
     else:
-        command += ' res=' + str(alg.getDefaultCellsize())
+        command += ' res=' + str(alg.getDefaultCellsize(parameters, context))
     alignToResolution = alg.getParameterValue(alg.GRASS_REGION_ALIGN_TO_RESOLUTION)
     if alignToResolution:
         command += ' -a'
diff --git a/python/plugins/processing/algs/grass7/ext/r_colors_stddev.py b/python/plugins/processing/algs/grass7/ext/r_colors_stddev.py
index 1a27c4dbb5b..0bc283a583f 100644
--- a/python/plugins/processing/algs/grass7/ext/r_colors_stddev.py
+++ b/python/plugins/processing/algs/grass7/ext/r_colors_stddev.py
@@ -53,7 +53,7 @@ def processInputs(alg):
     if cellsize:
         command += ' res=' + str(cellsize)
     else:
-        command += ' res=' + str(alg.getDefaultCellsize())
+        command += ' res=' + str(alg.getDefaultCellsize(parameters, context))
     alignToResolution = alg.getParameterValue(alg.GRASS_REGION_ALIGN_TO_RESOLUTION)
     if alignToResolution:
         command += ' -a'
diff --git a/python/plugins/processing/algs/grass7/ext/r_mapcalc.py b/python/plugins/processing/algs/grass7/ext/r_mapcalc.py
index 58d35f7b23a..546c90448c5 100644
--- a/python/plugins/processing/algs/grass7/ext/r_mapcalc.py
+++ b/python/plugins/processing/algs/grass7/ext/r_mapcalc.py
@@ -67,7 +67,7 @@ def processInputs(alg):
     if cellsize:
         command += ' res=' + str(cellsize)
     else:
-        command += ' res=' + str(alg.getDefaultCellsize())
+        command += ' res=' + str(alg.getDefaultCellsize(parameters,context))
     alignToResolution = alg.getParameterValue(alg.GRASS_REGION_ALIGN_TO_RESOLUTION)
     if alignToResolution:
         command += ' -a'
diff --git a/python/plugins/processing/algs/grass7/ext/r_null.py b/python/plugins/processing/algs/grass7/ext/r_null.py
index 9f73aa2ed4e..9f3440e057c 100644
--- a/python/plugins/processing/algs/grass7/ext/r_null.py
+++ b/python/plugins/processing/algs/grass7/ext/r_null.py
@@ -62,7 +62,7 @@ def processInputs(alg):
     if cellsize:
         command += ' res=' + str(cellsize)
     else:
-        command += ' res=' + str(alg.getDefaultCellsize())
+        command += ' res=' + str(alg.getDefaultCellsize(parameters,context))
     alignToResolution = alg.getParameterValue(alg.GRASS_REGION_ALIGN_TO_RESOLUTION)
     if alignToResolution:
         command += ' -a'
diff --git a/python/plugins/processing/algs/grass7/ext/r_rgb.py b/python/plugins/processing/algs/grass7/ext/r_rgb.py
index 02b36b24e5b..7b5e3525ac5 100644
--- a/python/plugins/processing/algs/grass7/ext/r_rgb.py
+++ b/python/plugins/processing/algs/grass7/ext/r_rgb.py
@@ -55,7 +55,7 @@ def processInputs(alg):
     if cellsize:
         command += ' res=' + str(cellsize)
     else:
-        command += ' res=' + str(alg.getDefaultCellsize())
+        command += ' res=' + str(alg.getDefaultCellsize(parameters,context))
     alignToResolution = alg.getParameterValue(alg.GRASS_REGION_ALIGN_TO_RESOLUTION)
     if alignToResolution:
         command += ' -a'
diff --git a/python/plugins/processing/algs/grass7/ext/r_shade.py b/python/plugins/processing/algs/grass7/ext/r_shade.py
index af57d6b8669..ffc4a709b72 100644
--- a/python/plugins/processing/algs/grass7/ext/r_shade.py
+++ b/python/plugins/processing/algs/grass7/ext/r_shade.py
@@ -63,7 +63,7 @@ def processInputs(alg):
     if cellsize:
         command += ' res=' + str(cellsize)
     else:
-        command += ' res=' + str(alg.getDefaultCellsize())
+        command += ' res=' + str(alg.getDefaultCellsize(parameters,context))
     alignToResolution = alg.getParameterValue(alg.GRASS_REGION_ALIGN_TO_RESOLUTION)
     if alignToResolution:
         command += ' -a'
diff --git a/python/plugins/processing/algs/grass7/ext/r_what_color.py b/python/plugins/processing/algs/grass7/ext/r_what_color.py
index 53f88fbc803..ad111cfb1aa 100644
--- a/python/plugins/processing/algs/grass7/ext/r_what_color.py
+++ b/python/plugins/processing/algs/grass7/ext/r_what_color.py
@@ -53,7 +53,7 @@ def processInputs(alg):
     if cellsize:
         command += ' res=' + str(cellsize)
     else:
-        command += ' res=' + str(alg.getDefaultCellsize())
+        command += ' res=' + str(alg.getDefaultCellsize(parameters,context))
     alignToResolution = alg.getParameterValue(alg.GRASS_REGION_ALIGN_TO_RESOLUTION)
     if alignToResolution:
         command += ' -a'
diff --git a/python/plugins/processing/algs/grass7/ext/v_lrs_segment.py b/python/plugins/processing/algs/grass7/ext/v_lrs_segment.py
index 8c5570bf10c..4d699f209f4 100644
--- a/python/plugins/processing/algs/grass7/ext/v_lrs_segment.py
+++ b/python/plugins/processing/algs/grass7/ext/v_lrs_segment.py
@@ -45,7 +45,7 @@ def processInputs(alg):
         alg.exportedLayers[rstable]
     )
     alg.commands.append(command)
-    alg.processInputs()
+    alg.processInputs(context,parameters)
 
 
 def processCommand(alg, parameters):
diff --git a/python/plugins/processing/algs/grass7/ext/v_lrs_where.py b/python/plugins/processing/algs/grass7/ext/v_lrs_where.py
index bd88625ba2a..0aef023f02d 100644
--- a/python/plugins/processing/algs/grass7/ext/v_lrs_where.py
+++ b/python/plugins/processing/algs/grass7/ext/v_lrs_where.py
@@ -37,7 +37,7 @@ def processInputs(alg):
         alg.exportedLayers[rstable]
     )
     alg.commands.append(command)
-    alg.processInputs()
+    alg.processInputs(parameters,context)
 
 
 def processCommand(alg, parameters):
diff --git a/python/plugins/processing/algs/grass7/nviz7.py b/python/plugins/processing/algs/grass7/nviz7.py
index aec5857cd7b..e60cabd57ae 100644
--- a/python/plugins/processing/algs/grass7/nviz7.py
+++ b/python/plugins/processing/algs/grass7/nviz7.py
@@ -115,7 +115,7 @@ class nviz7(GeoAlgorithm):
         if cellsize:
             command += ' res=' + str(cellsize)
         else:
-            command += ' res=' + str(self.getDefaultCellsize())
+            command += ' res=' + str(self.getDefaultCellsize(parameters,context))
         commands.append(command)
 
         command = 'nviz7'
@@ -170,22 +170,22 @@ class nviz7(GeoAlgorithm):
         command += ' --overwrite -o'
         return (command, destFilename)
 
-    def getDefaultCellsize(self):
+    def getDefaultCellsize(self, parameters, context):
         cellsize = 0
-        context = dataobjects.createContext()
-        for param in self.parameters:
-            if param.value:
+        for param in self.parameterDefinitions():
+            if param.name() in parameters:
+                value = parameters[param.name()]
                 if isinstance(param, ParameterRaster):
-                    if isinstance(param.value, QgsRasterLayer):
-                        layer = param.value
+                    if isinstance(value, QgsRasterLayer):
+                        layer = value
                     else:
-                        layer = QgsProcessingUtils.mapLayerFromString(param.value, context)
+                        layer = QgsProcessingUtils.mapLayerFromString(value, context)
                     cellsize = max(cellsize, (layer.extent().xMaximum() -
                                               layer.extent().xMinimum()) /
                                    layer.width())
                 elif isinstance(param, ParameterMultipleInput):
 
-                    layers = param.value.split(';')
+                    layers = value.split(';')
                     for layername in layers:
                         layer = QgsProcessingUtils.mapLayerFromString(layername, context)
                         if isinstance(layer, QgsRasterLayer):