Edit imports

README.md

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+**Project Developer: Alireza Adli**
+alireza.adli@mail.concordia.ca
+
+## Table of Contents
+
+[About mtl_gis_oo](#about-gispy)  
+[Building Cleanup Workflow](#workflowpy)
+[ScrubLayer](#scrublayer)  
+[Helpers](#helpers)
+[Configuration](#config)
+[ScrubMTL](#scrubmtl)
+[Setting up an environment to use standalone PyQGIS – How to import qgis.core](#setting-up)
+
+<a name="about-gispy"/>
+
+## About mtl_gis_oo
+
+This project automates the process of integrating and cleaning datasets related to Montreal buildings.
+It is the continuation of [hydroquebec_archetype_gispy](https://ngci.encs.concordia.ca/gitea/a_adli/hydroquebec_archetype_gispy). The project involves the following datasets:
+
+1. [NRCAN Building Footprints](https://open.canada.ca/data/en/dataset/7a5cda52-c7df-427f-9ced-26f19a8a64d6)
+2. [Shared platform of geospatial data and aerial photographs (GeoIndex)](https://geoapp.bibl.ulaval.ca/)
+3. [Montreal Property Assesment Units](https://donnees.montreal.ca/dataset/unites-evaluation-fonciere)
+4. [Administrative boundaries of the agglomeration of Montréal (boroughs and related cities)](https://donnees.montreal.ca/dataset/limites-administratives-agglomeration)
+
+The original workflow was developed in ArcGIS by Kartikay Sharma (kartikay.sharma@concordia.ca). This workflow (link) involves steps such as fixing and clipping geometries, removing features from unnecessary parts of the map, splitting sections based on single building footprints, spatially joining datasets, and cleaning the data through processes such as removing duplicates, among others.
+
+GISPy integrates these processes and automates them so that users can update the dataset by running the workflow module (building_cleanup_workflow.py) after acquiring and defining the paths to the mentioned datasets.
+
+GISPy has been written using QGIS Python standalone libraries (PyQGIS). This set of libraries leverages the functionality of QGIS without needing to run the full QGIS desktop application. To use the environment, QGIS needs to be installed, and the environment must be set up ([Setting up an environment to use standalone PyQGIS – How to import qgis.core](#setting-up)).
+
+<a name="#scrublayer"/>
+
+## ScrubLayer
+
+This module is the essence of the mtl_gis_oo project. It encompasses required functionalities of PyQGIS as methods. Some other methods also have been added to use the functionalities in a specific way. For example, clip_by_multiply carry outs PyQGIS clipping using multiple overlay layers.
+
+<a name="#workflowpy"/>
+
+## Building Cleanup Workflow
+
+This is the process of cleaning and aggregating Montreal buildings datasets. This workflow is backed up by ScrubLayer. After defining the paths, running the module outputs the updated and integrated dataset (map layer).
+
+<a name="helpers"/>
+
+## Helpers
+
+The module contains several functions that cannot be defines as a method of ScrubLayer class but are useful and sometimes necessary for a method or a part of the workflow (building_cleanup_workflow.py).
+Creating folders, finding a type of files and merging layers are examples of the module's functionalities.
+
+<a name="config"/>
+
+## Configuration
+
+This module contains the QGIS installation path, and two dictionaries for holding input and output layers paths. The module will be modified completely to address paths in a general way instead of locally.
+
+<a name="scrubmtl"/>
+## ScrubMTL
+
+This module is not being used or developed right now.
+
+<a name="setting-up"/>
+
+## Setting up an environment to use standalone PyQGIS – How to import qgis.core
+
+To use PyQGIS without having the QGIS application run in the background, one needs to add the python path to the environment variables. Here is how to do it on Windows:
+
+1. Install QGIS
+
+2. Assign a specific name to the QGIS Python executable:
+   This is being done in order to access the QGIS Python from the command prompt without mixing with the system’s original Python installation(s).
+
+   a. Go to the QGIS installation directory’s Python folder. e.g. C:\Program Files\QGIS 3.34.1\apps\Python39  
+   b. Rename the Python executable (python.exe) to a specific-desired name, e.g. pythonqgis.exe
+
+3. Updating the Path variables
+
+   a. Go to Environmental Variables (from Windows start)  
+   b. Click on Path and then click on Edit. Add the following paths:
+
+   > C:\Program Files\QGIS 3.34.1\apps\Python39
+
+   c. Go back to the Environmental variables this time click on New and in New Variable box enter PYTHONPATH and in the Variable Value add the following paths (separate them with a colon). Some paths might be different. For example, apps\qgis can be apps\qgis-ltr.
+
+   > i. C:\Program Files\QGIS 3.34.1\apps\qgis\python  
+   > ii. C:\Program Files\QGIS 3.34.1\apps\qgis\python\plugins  
+   > iii. C:\Program Files\QGIS 3.34.1\apps\Qt5\plugins  
+   > iv. C:\Program Files\QGIS 3.34.1\apps\gdal\share\gdal  
+   > v. Or altogether: C:\Program Files\QGIS 3.34.1\apps\qgis\python;C:\Program Files\QGIS 3.34.1\apps\qgis\python\plugins;C:\Program Files\QGIS 3.34.1\apps\Qt5\plugins;C:\Program Files\QGIS 3.34.1\apps\gdal\share\gdal
+
+4. Validate importing qgis.core
+
+   a. Open a command prompt window
+   b. Enter pythonqgis  
+   c. If the process has been done correctly, you won’t face any error.  
+   d. In the Python environment, import the package by:
+
+   > import qgis.core

building_cleanup_workflow.py

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+"""
+handle_mtl_ds_workflow module
+The workflow of cleaning and updating the Montreal Buildings dataset.
+Project Developer: Alireza Adli alireza.adli@concordia.ca
+The original workflow was developed in ArcGIS by
+Kartikay Sharma (kartikay.sharma@concordia.ca).
+"""
+
+from scrub_layer import ScrubLayer
+from config import qgis_path, input_paths, output_paths, output_paths_dir
+from helpers import create_output_folders
+# Making folders for the output data layers
+create_output_folders(output_paths, output_paths_dir)
+
+# Initialize the input data layers
+nrcan = ScrubLayer(qgis_path, input_paths['NRCan'], 'NRCan')
+geo_index = ScrubLayer(qgis_path, input_paths['GeoIndex'], 'GeoIndex')
+property_assessment = \
+  ScrubLayer(
+    qgis_path, input_paths['Property Assessment'], 'Property Assessment')
+montreal_boundary = \
+  ScrubLayer(qgis_path, input_paths['Montreal Boundary'], 'Montreal Boundary')
+
+# Processing the NRCan layer includes fixing its geometries
+print('Processing the NRCan layer')
+print(nrcan)
+nrcan.create_spatial_index()
+nrcan.fix_geometries(output_paths['Fixed NRCan'])
+
+# Defining a new layer for the fixed NRCan
+nrcan_fixed = \
+  ScrubLayer(qgis_path, output_paths['Fixed NRCan'], 'Fixed NRCan')
+nrcan_fixed.create_spatial_index()
+print(nrcan_fixed)
+
+# Processing the GeoIndex layer includes fixing its geometries and
+# clipping it based on the Montreal boundary data layer
+print('Processing the GeoIndex layer')
+print(geo_index)
+geo_index.create_spatial_index()
+geo_index.fix_geometries(output_paths['Fixed GeoIndex'])
+
+# Defining a new layer for the fixed GeoIndex
+geo_index_fixed = ScrubLayer(qgis_path, output_paths['Fixed GeoIndex'],
+                             'Fixed GeoIndex')
+geo_index_fixed.create_spatial_index()
+print(geo_index_fixed)
+geo_index_fixed.clip_layer(montreal_boundary.layer_path,
+                           output_paths['Clipped Fixed GeoIndex'])
+geo_index_clipped = \
+  ScrubLayer(qgis_path,
+             output_paths['Clipped Fixed GeoIndex'], 'Clipped Fixed GeoIndex')
+geo_index_clipped.create_spatial_index()
+print(geo_index_clipped)
+
+# Processing the Property Assessment layer includes a pairwise clip, and
+# two spatial join with NRCan and GeoIndex layers, respectively
+
+print(property_assessment)
+property_assessment.create_spatial_index()
+
+# For the pairwise clip, number of overlaying layers can be chosen
+# (meaning number of splits for NRCan layer). This improves the performance
+# where may increase duplicates. This has been done because using the NRCan
+# layer as a whole causes crashing the clipping process.
+
+# First we split the overlaying layers into our desired number
+nrcan_fixed.split_layer(120, output_paths['Splitted NRCans'])
+
+# Clipping have to be done in
+clipping_property_assessment = """
+from input_paths_and_layers import *
+
+property_assessment.clip_by_multiple(
+  120, output_paths['Splitted NRCans'],
+  output_paths['Pairwise Clipped Property Assessment Partitions'])"""
+
+exec(clipping_property_assessment)
+
+property_assessment.merge_layers(
+  output_paths['Pairwise Clipped Property Assessment Partitions'],
+  output_paths['Pairwise Clipped Merged Property Assessment'])
+
+clipped_property_assessment = ScrubLayer(
+  qgis_path,
+  output_paths['Pairwise Clipped Merged Property Assessment'],
+  'Clipped Property Assessment')
+
+print(clipped_property_assessment)
+clipped_property_assessment.create_spatial_index()
+
+clipped_property_assessment.spatial_join(
+  nrcan_fixed.layer_path,
+  output_paths['Property Assessment and NRCan'])
+
+property_assessment_nrcan = ScrubLayer(
+  qgis_path,
+  output_paths['Property Assessment and NRCan'],
+  'Property Assessment and NRCan')
+
+print(property_assessment_nrcan)
+property_assessment_nrcan.create_spatial_index()
+
+property_assessment_nrcan.spatial_join(
+  geo_index_clipped,
+  output_paths['Property Assessment and NRCan and GeoIndex'])
+
+property_assessment_nrcan_geo = ScrubLayer(
+  qgis_path,
+  output_paths['Property Assessment and NRCan and GeoIndex'],
+  'Property Assessment and NRCan and GeoIndex')
+
+print(property_assessment_nrcan_geo)
+property_assessment_nrcan_geo.create_spatial_index()
+
+property_assessment_nrcan_geo.delete_duplicates(
+  output_paths['Deleted Duplicates Layer'])
+
+deleted_dups_layer = ScrubLayer(
+  qgis_path,
+  output_paths['Deleted Duplicates Layer'],
+  'Deleted Duplicates Layer')
+
+print(deleted_dups_layer)
+property_assessment_nrcan_geo.create_spatial_index()
+
+property_assessment_nrcan_geo.multipart_to_singleparts(
+  output_paths['Single Parts Layer'])
+
+single_parts_layer = ScrubLayer(
+  qgis_path,
+  output_paths['Single Parts Layer'],
+  'Single Parts Layer')
+
+print(single_parts_layer)
+single_parts_layer.create_spatial_index()
+
+# Add an area field
+single_parts_layer.add_field('Area')
+single_parts_layer.assign_area('Area')
+dismissive_area = 15
+single_parts_layer.conditional_delete_record('Area', '<', dismissive_area)
+
+print(f'After removing buildings with less than {dismissive_area} squaremeter area:')
+print(single_parts_layer)
+

config.py

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+"""
+input_paths_and_layers module
+Project Developer: Alireza Adli alireza.adli@concordia.ca
+"""
+
+# Application's path
+qgis_path = 'C:/Program Files/QGIS 3.34.1/apps/qgis'
+
+# Gathering input data layers paths
+input_paths = {
+  'NRCan':
+  'C:/Users/a_adli/PycharmProjects/hydroquebec_archetype_gispy/'
+  'data/input_data/nrcan/Autobuilding_QC_VILLE_MONTREAL.shp',
+  'GeoIndex':
+  'C:/Users/a_adli/PycharmProjects/hydroquebec_archetype_gispy/'
+  'data/input_data/Geoindex_81670/mamh_usage_predo_2022_s_poly.shp',
+  'Property Assessment':
+  'C:/Users/a_adli/PycharmProjects/hydroquebec_archetype_gispy/'
+  'data/input_data/property_assessment/uniteevaluationfonciere.shp',
+  'Montreal Boundary':
+  'C:/Users/a_adli/PycharmProjects/hydroquebec_archetype_gispy/'
+  'data/input_data/montreal_boundary/Montreal_boundary.shp'
+}
+
+# Defining a directory for all the output data layers
+output_paths_dir = \
+  'C:/Users/a_adli/PycharmProjects/hydroquebec_archetype_gispy/' \
+  'data/gisoo_workflow_output'
+
+# Preparing a bedding for output data layers paths
+output_paths = {
+  'Fixed NRCan': '',
+  'Fixed GeoIndex': '',
+  'Clipped Fixed GeoIndex': '',
+  'Splitted NRCans': '',
+  'Pairwise Clipped Property Assessment Partitions': '',
+  'Pairwise Clipped Merged Property Assessment': '',
+  'Property Assessment and NRCan': '',
+  'Property Assessment and NRCan and GeoIndex': '',
+  'Deleted Duplicates Layer': '',
+  'Single Parts Layer': ''
+}

helpers.py

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+"""
+basic_functions module
+A number of functionalities that help the project
+but cannot be a part of the PyQGIS tool.
+Project Developer: Alireza Adli alireza.adli@concordia.ca
+"""
+
+import os
+import glob
+import processing
+
+from qgis.core import QgsApplication
+from qgis.analysis import QgsNativeAlgorithms
+
+
+def find_shp_files(root_folder):
+  shp_files = []
+  # Sort folders alphabetically
+  for foldername, _, _ in sorted(os.walk(root_folder)):
+    for filename in sorted(glob.glob(os.path.join(foldername, '*.shp'))):
+      new_file_name = filename.replace('\\', r'/')
+      shp_files.append(new_file_name)
+  return shp_files
+
+
+def find_las_files(root_folder):
+  las_files = []
+  # Sort folders alphabetically
+  for foldername, _, _ in sorted(os.walk(root_folder)):
+    for filename in sorted(glob.glob(os.path.join(foldername, '*.las'))):
+      new_file_name = filename.replace('\\', r'/')
+      las_files.append(new_file_name)
+  return las_files
+
+
+def create_folders(directory, num_folders):
+  """
+  Create a specified number of folders in the given directory.
+
+  Args:
+  - directory (str): The directory where folders will be created.
+  - num_folders (int): The number of folders to create.
+  """
+  # Check if the directory exists, if not, create it
+  if not os.path.exists(directory):
+    os.makedirs(directory)
+
+  # Create folders
+  for i in range(num_folders):
+    folder_name = f"layer_{i}"
+    folder_path = os.path.join(directory, folder_name)
+    os.makedirs(folder_path)
+    print(f"Created folder: {folder_path}")
+
+
+def create_output_folders(paths_dict, output_dir):
+  for path in paths_dict.keys():
+    new_folder = path.lower().replace(' ', '_')
+    output_path = output_dir + '/' + new_folder
+    os.mkdir(output_path)
+    if path[-1] != 's':
+      paths_dict[path] = output_path + f'/{new_folder}.shp'
+    else:
+      paths_dict[path] = output_path
+
+
+def merge_las_layers(layers_path, mergeded_layer_path):
+  merging_layers = find_las_files(layers_path)
+  QgsApplication.processingRegistry().addProvider(QgsNativeAlgorithms())
+
+  params = {'LAYERS': merging_layers,
+            'CRS': None,
+            'OUTPUT': mergeded_layer_path}
+
+  processing.run("native:mergevectorlayers", params)

scrub_layer.py

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+"""
+scrub_layer_class module
+PyQGIS functionalities that are needed in the cleaning and updating
+Montreal Buildings dataset project, gathered in one class.
+Project Developer: Alireza Adli alireza.adli@concordia.ca
+"""
+import os
+import processing
+
+from qgis.core import QgsApplication, QgsField, QgsProject, \
+  QgsProcessingFeedback, QgsVectorLayer, QgsVectorDataProvider, \
+  QgsExpressionContext, QgsExpressionContextUtils, edit, QgsFeatureRequest, \
+  QgsExpression, QgsVectorFileWriter, QgsCoordinateReferenceSystem
+from qgis.PyQt.QtCore import QVariant
+from qgis.analysis import QgsNativeAlgorithms
+from helpers import create_folders,  find_shp_files
+
+
+class ScrubLayer:
+  def __init__(self, qgis_path, layer_path, layer_name):
+
+    self.qgis_path = qgis_path
+    # Set the path to QGIS installation
+    QgsApplication.setPrefixPath(self.qgis_path, True)
+
+    self.layer_path = layer_path
+    self.layer_name = layer_name
+    self.layer = self.load_layer()
+    self.data_count = self.layer.featureCount()
+
+  def duplicate_layer(self, output_path):
+    options = QgsVectorFileWriter.SaveVectorOptions()
+    options.driverName = 'ESRI Shapefile'
+
+    duplication = QgsVectorFileWriter.writeAsVectorFormat(
+      self.layer,
+      output_path,
+      options
+    )
+
+    if duplication == QgsVectorFileWriter.NoError:
+      print(f"Shapefile successfully duplicated")
+    else:
+      print(f"Error duplicating shapefile: {duplication}")
+
+  def get_cell(self, fid, field_name):
+    return self.layer.getFeature(fid)[field_name]
+
+  def select_cells(
+          self,
+          field_name, field_value, required_field,
+          return_one_value=False):
+    """Returns the value of a field
+    based on the value of another field in the same record"""
+    expression = QgsExpression(f'{field_name} = {field_value}')
+    request = QgsFeatureRequest(expression)
+    features = self.layer.getFeatures(request)
+    field_field_values = []
+    for feature in features:
+      field_field_values.append(feature[required_field])
+      if return_one_value and field_field_values:
+        return field_field_values[0]
+    return field_field_values
+
+  def load_layer(self):
+    the_layer = QgsVectorLayer(self.layer_path, self.layer_name, 'ogr')
+    if not the_layer.isValid():
+      raise ValueError(f'Failed to load layer {self.layer_name} from {self.layer_path}')
+    else:
+      QgsProject.instance().addMapLayer(the_layer)
+    return the_layer
+
+  def features_to_layers(self, layers_dir, crs):
+    create_folders(layers_dir, self.data_count)
+    target_crs = QgsCoordinateReferenceSystem(crs)
+    for feature in self.layer.getFeatures():
+      new_layer = QgsVectorLayer(f'Polygon?crs={crs}', "feature_layer", "memory")
+      new_layer.setCrs(target_crs)
+
+      new_provider = new_layer.dataProvider()
+      new_provider.addFeatures([feature])
+
+      feature_id = feature.id()
+      output_path = f'{layers_dir}layer_{feature_id}/layer_{feature_id}.shp'
+
+      QgsVectorFileWriter.writeAsVectorFormat(
+        new_layer,
+        output_path,
+        'utf-8',
+        new_layer.crs(),
+        'ESRI Shapefile'
+      )
+    print('Shapefiles created for each feature.')
+
+  def fix_geometries(self, fixed_layer):
+    QgsApplication.processingRegistry().addProvider(QgsNativeAlgorithms())
+    fix_geometries_params = {
+      'INPUT': self.layer,
+      'METHOD': 0,
+      'OUTPUT': fixed_layer
+    }
+    processing.run("native:fixgeometries", fix_geometries_params)
+
+  def create_spatial_index(self):
+    QgsApplication.processingRegistry().addProvider(QgsNativeAlgorithms())
+    create_spatial_index_params = {
+      'INPUT': self.layer,
+      'OUTPUT': 'Output'
+    }
+    processing.run("native:createspatialindex", create_spatial_index_params)
+    print(f'Creating Spatial index for {self.layer_name} is completed.')
+
+  def spatial_join(self, joining_layer_path, joined_layer_path):
+    """In QGIS, it is called 'Join attributes by Location'"""
+    params = {'INPUT': self.layer,
+              'PREDICATE': [0],
+              'JOIN': joining_layer_path,
+              'JOIN_FIELDS': [],
+              'METHOD': 0,
+              'DISCARD_NONMATCHING': False,
+              'PREFIX': '',
+              'OUTPUT': joined_layer_path}
+
+    feedback = QgsProcessingFeedback()
+    processing.run('native:joinattributesbylocation', params, feedback=feedback)
+    print(f'Spatial Join with input layer {self.layer_name} is completed.')
+
+  def clip_layer(self, overlay_layer, clipped_layer):
+    """This must be tested"""
+    QgsApplication.processingRegistry().addProvider(QgsNativeAlgorithms())
+    clip_layer_params = {
+      'INPUT': self.layer_path,
+      'OVERLAY': overlay_layer,
+      'FILTER_EXPRESSION': '',
+      'FILTER_EXTENT': None,
+      'OUTPUT': clipped_layer
+    }
+    processing.run("native:clip", clip_layer_params)
+    print(f'Clipping of {self.layer_name} is completed.')
+
+  def clip_by_predefined_zones(self):
+    pass
+
+  def clip_by_multiple(self, number_of_partitions, overlay_layers_dir, clipped_layers_dir):
+    create_folders(clipped_layers_dir, number_of_partitions)
+    for layer in range(number_of_partitions):
+      overlay = overlay_layers_dir + f'/layer_{layer}/layer_{layer}.shp'
+      clipped = clipped_layers_dir + f'/layer_{layer}/layer_{layer}.shp'
+      self.clip_layer(overlay, clipped)
+      clipped_layer = ScrubLayer(self.qgis_path, clipped, 'Temp Layer')
+      clipped_layer.create_spatial_index()
+
+  def split_layer(self, number_of_layers, splitted_layers_dir):
+    number_of_layers -= 1
+    QgsApplication.processingRegistry().addProvider(QgsNativeAlgorithms())
+    create_folders(splitted_layers_dir, number_of_layers)
+    intervals = self.data_count // number_of_layers
+    for part in range(number_of_layers):
+      output_layer_path = \
+        splitted_layers_dir + f'/layer_{part}/layer_{part}.shp'
+      params = {'INPUT': self.layer,
+                'EXPRESSION': f'$id >= {part * intervals} '
+                              f'AND $id < {(part + 1) * intervals}\r\n',
+                'OUTPUT': output_layer_path}
+
+      processing.run("native:extractbyexpression", params)
+
+      new_layer = ScrubLayer(self.qgis_path, output_layer_path, 'Temp Layer')
+      new_layer.create_spatial_index()
+
+    # Adding a folder for the remaining features
+
+    os.makedirs(splitted_layers_dir + f'/layer_{number_of_layers}')
+    output_layer_path = splitted_layers_dir + \
+        f'/layer_{number_of_layers}/layer_{number_of_layers}.shp'
+    params = {'INPUT': self.layer,
+              'EXPRESSION': f'$id >= {number_of_layers * intervals}\r\n',
+              'OUTPUT': output_layer_path}
+
+    processing.run("native:extractbyexpression", params)
+    new_layer = ScrubLayer(self.qgis_path, output_layer_path, 'Temp Layer')
+    new_layer.create_spatial_index()
+
+  @staticmethod
+  def merge_layers(layers_path, mergeded_layer_path):
+    merging_layers = find_shp_files(layers_path)
+    QgsApplication.processingRegistry().addProvider(QgsNativeAlgorithms())
+
+    params = {'LAYERS': merging_layers,
+              'CRS': None,
+              'OUTPUT': mergeded_layer_path}
+
+    processing.run("native:mergevectorlayers", params)
+
+  def multipart_to_singleparts(self, singleparts_layer_path):
+    QgsApplication.processingRegistry().addProvider(QgsNativeAlgorithms())
+    params = {'INPUT': self.layer,
+              'OUTPUT': singleparts_layer_path}
+    processing.run("native:multiparttosingleparts", params)
+
+  def delete_duplicates(self, deleted_duplicates_layer):
+    QgsApplication.processingRegistry().addProvider(QgsNativeAlgorithms())
+    params = {'INPUT': self.layer_path,
+              'OUTPUT': deleted_duplicates_layer}
+    processing.run("native:deleteduplicategeometries", params)
+
+  def delete_field(self, field_name):
+    QgsApplication.processingRegistry().addProvider(QgsNativeAlgorithms())
+    with edit(self.layer):
+      # Get the index of the column to delete
+      idx = self.layer.fields().indexFromName(field_name)
+
+      # Delete the field
+      self.layer.deleteAttribute(idx)
+
+      # Update layer fields
+      self.layer.updateFields()
+
+  def delete_record_by_index(self, record_index):
+    self.layer.startEditing()
+
+    if self.layer.deleteFeature(record_index):
+      print(f"Feature with ID {record_index} has been successfully removed.")
+    else:
+      print(f"Failed to remove feature with ID {record_index}.")
+
+    self.layer.commitChanges()
+
+  def conditional_delete_record(self, field_name, operator, condition):
+    request = QgsFeatureRequest().setFilterExpression(
+      f'{field_name} {operator} {str(condition)}')
+    with edit(self.layer):
+      for feature in self.layer.getFeatures(request):
+        self.layer.deleteFeature(feature.id())
+    self.layer.commitChanges()
+
+  def add_field(self, new_field_name):
+    functionalities = self.layer.dataProvider().capabilities()
+
+    if functionalities & QgsVectorDataProvider.AddAttributes:
+      new_field = QgsField(new_field_name, QVariant.Double)
+      self.layer.dataProvider().addAttributes([new_field])
+      self.layer.updateFields()
+
+  def assign_area(self, field_name):
+    self.layer.startEditing()
+    idx = self.layer.fields().indexFromName(field_name)
+
+    context = QgsExpressionContext()
+    context.appendScopes(
+      QgsExpressionContextUtils.globalProjectLayerScopes(self.layer))
+
+    for feature in self.layer.getFeatures():
+      area = feature.geometry().area()
+      feature[idx] = area
+      self.layer.updateFeature(feature)
+
+    self.layer.commitChanges()
+
+  def __str__(self):
+    return f'The {self.layer_name} has {self.data_count} records.'
+
+  @staticmethod
+  def cleanup():
+    QgsApplication.exitQgis()
+
+
+
+

scrub_mtl.py

@@ -0,0 +1,131 @@
+"""
+scrub_mtl_class module
+The workflow of cleaning and updating the Montreal Buildings dataset.
+The development of this class has been stopped but the whole workflow
+can be found in a module namely handle_mtl_ds_workflow, in the same project.
+Project Developer: Alireza Adli alireza.adli@concordia.ca
+"""
+import os
+
+from scrub_layer import *
+from helpers import find_shp_files
+
+
+class ScrubMTL:
+  def __init__(self, qgis_path, nrcan, geo_index, property_assessment,
+               montreal_boundary, output_paths_dir):
+    self.qgis_path = qgis_path
+    self.nrcan = self.initialize_layer(nrcan, 'NRCan')
+    self.geo_index = self.initialize_layer(geo_index, 'GeoIndex')
+    self.property_assessment = \
+        self.initialize_layer(property_assessment, 'Property Assessment')
+    self.montreal_boundary = montreal_boundary
+    self.output_paths_dir = output_paths_dir
+    self.input_paths = {
+      'NRCan': nrcan,
+      'GeoIndex': geo_index,
+      'Property Assessment': property_assessment,
+      'Montreal Boundary': montreal_boundary
+     }
+    self.output_paths = {
+      'Fixed NRCan': '',
+      'Fixed GeoIndex': '',
+      'Clipped Fixed GeoIndex': '',
+      'Splitted NRCans': '',
+      'Pairwise Clipped Property Assessment Partitions': '',
+      'Pairwise Clipped Merged Property Assessment': '',
+      'Property Assessment and NRCan': '',
+      'Property Assessment and NRCan and GeoIndex': '',
+      'Deleted Duplicates Layer': '',
+      'Singled Parts Layer': ''
+    }
+
+  @staticmethod
+  def merge_layers(layers_path, mergeded_layer_path):
+    merging_layers = find_shp_files(layers_path)
+    QgsApplication.processingRegistry().addProvider(QgsNativeAlgorithms())
+
+    params = {'LAYERS': merging_layers,
+              'CRS': None,
+              'OUTPUT': mergeded_layer_path}
+
+    processing.run("native:mergevectorlayers", params)
+
+  def generate_output_paths(self):
+    for path in self.output_paths.keys():
+      new_folder = path.lower().replace(' ', '_')
+      output_path = self.output_paths_dir + '/' + new_folder
+      os.mkdir(output_path)
+      if path[-1] != 's':
+        self.output_paths[path] = output_path + f'/{new_folder}.shp'
+      else:
+        self.output_paths[path] = output_path
+
+  def initialize_layer(self, layer_path, layer_name):
+    return ScrubLayer(self.qgis_path, layer_path, layer_name)
+
+  def process_nrcan(self):
+    print(f'Data Count of the NRCan layer: {self.nrcan.data_count}')
+    self.nrcan.create_spatial_index()
+    self.nrcan.fix_geometries(self.output_paths['Fixed NRCan'])
+    nrcan_fixed = \
+        self.initialize_layer(self.output_paths['Fixed NRCan'],
+                              'Fixed NRCan')
+    nrcan_fixed.create_spatial_index()
+    print(f'Data Count of the NRCan layer ({nrcan_fixed.layer_name}) '
+          f'after fixing geometries: {nrcan_fixed.layer.featureCount()}')
+
+  def process_geo_index(self):
+    print(f'Data Count of the GeoIndex layer: {self.geo_index.data_count}')
+    self.geo_index.create_spatial_index()
+    self.geo_index.fix_geometries(self.output_paths['Fixed GeoIndex'])
+    geo_index_fixed = \
+        self.initialize_layer(self.output_paths['Fixed GeoIndex'],
+                              'Fixed GeoIndex')
+    geo_index_fixed.create_spatial_index()
+    print(f'Data Count of the GeoIndex layer ({geo_index_fixed.layer_name}) '
+          f'after fixing geometries: {geo_index_fixed.layer.featureCount()}')
+    geo_index_fixed.clip_layer(self.montreal_boundary,
+                               self.output_paths['Clipped Fixed GeoIndex'])
+    geo_index_clipped = \
+        self.initialize_layer(self.output_paths['Clipped Fixed GeoIndex'],
+                              'Clipped Fixed GeoIndex')
+    geo_index_clipped.create_spatial_index()
+    print(f'Data Count of the {geo_index_fixed.layer_name} '
+          f'({geo_index_clipped.layer_name}) after clipping it '
+          f'based on the Montreal Boundary layer: '
+          f'{geo_index_clipped.layer.featureCount()}')
+
+  def process_property_assesment(self):
+    print(f'Data Count of the Property Assessment layer: '
+          f'{self.property_assessment.data_count}')
+    self.property_assessment.create_spatial_index()
+
+  def the_cleaning_workflow(self):
+    """It carries out all the steps to clean the dataset."""
+    self.generate_output_paths()
+    self.process_nrcan()
+    self.process_geo_index()
+    self.process_property_assesment()
+    self.property_assessment.clip_by_multiple(120,
+                                              self.output_paths['Fixed NRCan'],
+                                              self.output_paths['Splitted NRCans'],
+                                              self.output_paths
+                                              ['Pairwise Clipped Property Assessment Partitions']
+                                              )
+    prop_a = ScrubLayer(self.qgis_path, self.input_paths['Property Assessment'],
+                        'Property Aim')
+
+    prop_a.\
+        clip_by_multiple(120, 'the path',
+                         self.output_paths['Splitted NRCans'])
+
+  def refine_heights(self):
+    pass
+
+  def remove_redundant_fields(self):
+    pass
+
+  def remove_records_by_area(self, area_limitation):
+    """Area limitation can be assigned in the constructor"""
+    pass