adding 2nd algorithm to merge and rename bands

merge_rename_bands_algorithm.py

+# -*- coding: utf-8 -*-
+
+"""
+/***************************************************************************
+ MergeAndRename
+                                 A QGIS plugin
+ Merge and rename raster bands
+ Generated by Plugin Builder: http://g-sherman.github.io/Qgis-Plugin-Builder/
+                              -------------------
+        begin                : 2021-09-09
+        copyright            : (C) 2021 by J. Pierson, UMR 6554 LETG, CNRS
+        email                : julie.pierson@univ-brest.fr
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   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__ = 'J. Pierson, UMR 6554 LETG, CNRS'
+__date__ = '2021-09-09'
+__copyright__ = '(C) 2021 by J. Pierson, UMR 6554 LETG, CNRS'
+
+# This will get replaced with a git SHA1 when you do a git archive
+
+__revision__ = '$Format:%H$'
+
+from qgis.PyQt.QtCore import QCoreApplication
+from qgis.core import (QgsProcessing,
+                       QgsProcessingAlgorithm,
+                       QgsProcessingParameterRasterLayer,
+                       QgsProcessingParameterMatrix,
+                       QgsProcessingParameterRasterDestination)
+from osgeo import gdal
+
+
+class MergeAndRenameAlgorithm(QgsProcessingAlgorithm):
+    """
+    This is an algorithm that takes a raster layer and
+    rename and/or reorder its bands.
+    """
+
+    # Constants used to refer to parameters and outputs. They will be
+    # used when calling the algorithm from another algorithm, or when
+    # calling from the QGIS console.
+
+    INPUT = 'INPUT'
+    TABLE = 'TABLE'
+    OUTPUT = 'OUTPUT'
+
+    def initAlgorithm(self, config):
+        """
+        Here we define the inputs and output of the algorithm, along
+        with some other properties.
+        """
+
+        # input raster layer
+        self.addParameter(
+            QgsProcessingParameterRasterLayer(
+                self.INPUT,
+                self.tr('Input raster layer'),
+                [QgsProcessing.TypeVectorAnyGeometry]
+            )
+        )
+        
+        # table to reaorder and rename bands
+        self.addParameter(
+            QgsProcessingParameterMatrix(
+                self.TABLE, 
+                self.tr('Band names and order'), 
+                numberRows=0, 
+                hasFixedNumberRows = False, 
+                headers=['future name', 'order'], 
+                defaultValue=[None,None]
+            )
+        )
+            
+        # output raster layer
+        self.addParameter(
+            QgsProcessingParameterRasterDestination(
+                'OUTPUT',
+                self.tr('Raster output')
+            )
+        )
+
+
+
+    def processAlgorithm(self, parameters, context, feedback):
+        """
+        Here is where the processing itself takes place.
+        """
+
+        # RETRIEVE INPUTS AND OUTPUT
+        input_raster = self.parameterAsRasterLayer(parameters, self.INPUT, context)
+        band_table = self.parameterAsMatrix(parameters, self.TABLE, context)
+        output_raster_path = self.parameterAsOutputLayer(parameters, self.OUTPUT, context)
+        
+        # GETTING USEFUL PAREMETERS
+        
+        # number of columns in table is used later on, change it here if necessary
+        nb_col = 2
+        # index of column used for band order
+        index_bandorder = 1
+        # index of column used for band description
+        index_banddesc = 0
+        
+        # transform band_table in a nested list, with 1 element per band, and name and order of each band
+        # [['band 1', 1], ['band 2', 2], ['band 3', 3]]
+        band_table = [band_table[n:n+nb_col] for n in range(0, len(band_table), nb_col)]
+        # get input raster path
+        input_raster_path = input_raster.source()
+        # read raster with gdal
+        input_raster = gdal.Open(input_raster_path)
+        
+        
+        # REORDERING BANDS
+        
+        # get order of bands as a list, i.e. [3,2,1]
+        band_order = [i[index_bandorder] for i in band_table]
+        # reordering bands using gdal_translate
+        kwargs = {
+                'bandList': band_order
+                }
+        output_raster = gdal.Translate(output_raster_path, input_raster_path, **kwargs)
+        
+        
+        # RENAMING BANDS
+        
+        # get number of bands of input raster
+        nbands = input_raster.RasterCount
+        # get number of rows in table
+        nrows = len(band_table)
+        # check if band number = row count in band_table
+        if nbands != nrows:
+            message = 'Number of rows in table is different from number of bands in input raster'
+            feedback.reportError(QCoreApplication.translate('Rename bands', message))
+            return{}
+        
+        # reorder band table so that bands are in same order as in output raster
+        sorted_band_table = sorted(band_table, key = lambda x: x[index_bandorder])
+        
+        # iterate over each band to set its description using table input
+        for band_number in range(nbands):
+            band = output_raster.GetRasterBand(band_number + 1)
+            band.SetDescription(sorted_band_table[band_number][index_banddesc])
+            
+            
+        # RETURNING RESULTS
+
+        # Return the results of the algorithm as a dictionary
+        return {self.OUTPUT: output_raster_path}
+
+    def name(self):
+        """
+        Returns the algorithm name, used for identifying the algorithm. This
+        string should be fixed for the algorithm, and must not be localised.
+        The name should be unique within each provider. Names should contain
+        lowercase alphanumeric characters only and no spaces or other
+        formatting characters.
+        """
+        return 'Merge and rename bands'
+
+    def displayName(self):
+        """
+        Returns the translated algorithm name, which should be used for any
+        user-visible display of the algorithm name.
+        """
+        return self.tr(self.name())
+
+    def group(self):
+        """
+        Returns the name of the group this algorithm belongs to. This string
+        should be localised.
+        """
+        return self.tr(self.groupId())
+
+    def groupId(self):
+        """
+        Returns the unique ID of the group this algorithm belongs to. This
+        string should be fixed for the algorithm, and must not be localised.
+        The group id should be unique within each provider. Group id should
+        contain lowercase alphanumeric characters only and no spaces or other
+        formatting characters.
+        """
+        return ''
+
+    def tr(self, string):
+        return QCoreApplication.translate('Processing', string)
+
+    def createInstance(self):
+        return MergeAndRenameAlgorithm()

rename_bands_provider.py

@@ -32,6 +32,7 @@ __revision__ = '$Format:%H$'
 
 from qgis.core import QgsProcessingProvider
 from .rename_bands_algorithm import RenameBandsAlgorithm
+from .merge_rename_bands_algorithm import MergeAndRenameAlgorithm
 
 
 class RenameBandsProvider(QgsProcessingProvider):
@@ -54,8 +55,7 @@ class RenameBandsProvider(QgsProcessingProvider):
         Loads all algorithms belonging to this provider.
         """
         self.addAlgorithm(RenameBandsAlgorithm())
-        # add additional algorithms here
-        # self.addAlgorithm(MyOtherAlgorithm())
+        self.addAlgorithm(MergeAndRenameAlgorithm())
 
     def id(self):
         """