Added feature to read built-up areas from the OBM Tiles database

.gitignore

@@ -6,6 +6,7 @@ Pipfile
 Pipfile.lock
 .idea
 .coverage
+*.env
 
 __pycache__
 .cache

.gitlab-ci.yml

 image: python:3-buster
 
+services:
+  - postgres:13.3
+
 # Make pip cache the installed dependencies
 variables:
   PIP_CACHE_DIR: "$CI_PROJECT_DIR/.cache/pip"
+  POSTGRES_DB: testdatabase
+  POSTGRES_USER: tester
+  POSTGRES_PASSWORD: somepass
+  GDEIMPORTER_DB_HOST: postgres
+  GDEIMPORTER_DB: ${POSTGRES_DB}
+  GDEIMPORTER_USER: ${POSTGRES_USER}
+  GDEIMPORTER_PASSWORD: ${POSTGRES_PASSWORD}
+  GDEIMPORTER_SOURCEID: 1
+
 cache:
   paths:
     - .cache/pip

config_example.yml

@@ -5,3 +5,10 @@ boundaries_pathname: path_to_directory_with_boundary_files
 occupancies_to_run: residential, commercial  # Need to exist for the indicated `exposure format`, industrial not supported
 exposure_entities_to_run: all  # Either "all", a comma-space-separated list of entity names, or a name of a .txt or .csv file
 number_cores: 1  # Number of cores used for parallelisation
+database_built_up:  # Database where built-up areas per quadtile are stored
+  host: host_name
+  dbname: database_name
+  port: port_number  # Leave empty if a port number is not needed
+  username: username
+  password: password_of_username
+  sourceid: 1

gdeimporter/configuration.py

@@ -16,8 +16,10 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program. If not, see http://www.gnu.org/licenses/.
 
+import os
 import logging
 import yaml
+from dotenv import load_dotenv
 
 logger = logging.getLogger()
 
@@ -42,6 +44,22 @@ class Configuration:
             List of names of the exposure entities for which the data units will be retrieved.
         self.number_cores (int):
             Number of cores that will be used to run the code.
+        self.database_built_up (dict):
+            Dictionary containing the credentials needed to connect to the SQL database in which
+            the built-up area per quadtile is stored. The exact parameters needed depend on the
+            database. They can be:
+                host (str):
+                    SQL database host address.
+                dbname (str):
+                    Name of the SQL database.
+                port (int):
+                    Port where the SQL database can be found.
+                username (str):
+                    User name to connect to the SQL database.
+                password (str):
+                    Password associated with self.username.
+                sourceid (int):
+                    ID of the built-up area source dataset that will be sought for.
     """
 
     REQUIRES = [
@@ -50,13 +68,20 @@ class Configuration:
         "occupancies_to_run",
         "exposure_entities_to_run",
         "number_cores",
+        "database_built_up",
     ]
 
-    def __init__(self, filepath):
+    def __init__(self, filepath, force_config_over_hierarchies=False):
         """
         Args:
             filepath (str):
                 Full file path to the .yml configuration file.
+            force_config_over_hierarchies (bool):
+                If True, the contents of the .yml configuration file specified in filepath will
+                take precedence over any other hierarchy (e.g. preference of environment
+                variables if they exist). If False, hierarchies of preference established in
+                this class are applied. This parameter is used for forcing the testing of this
+                class under certain circumstances. Default: False.
         """
 
         config = self.read_config_file(filepath)
@@ -71,6 +96,9 @@ class Configuration:
             config, "exposure_entities_to_run"
         )
         self.number_cores = self._assign_integer_parameter(config, "number_cores")
+        self.database_built_up = self._retrieve_database_credentials(
+            config, "database_built_up", "test_db_built_up.env", force_config_over_hierarchies
+        )
 
         # Terminate if critical parameters are missing (not all parameters are critical)
         for key_parameter in self.REQUIRES:
@@ -242,3 +270,124 @@ class Configuration:
             assigned_parameter = None
 
         return assigned_parameter
+
+    def _assign_hierarchical_parameters(self, config, input_parameter, requested_nested=[]):
+        """This function searches for the key input_parameter in the dictionary config, and for
+        each of the elements of requested_nested as keys of config[input_parameter].
+
+        If input_parameter is not a key of config, the output is None.
+
+        If input_parameter is a key of config, but one of the elements of requested_nested is
+        not a key of config[input_parameter], the output is None.
+
+        Args:
+            config (dictionary):
+                The configuration file read as a dictionary. It may be an empty dictionary.
+            input_parameter (str):
+                Name of the desired parameter, to be searched for as a primary key of config.
+            requested_nested (list of str):
+                List of the names of the desired nested parameters, to be searched for as keys
+                of config[input_parameter]. If empty, the function will retrieve all nested
+                parameters available in 'config'.
+
+        Returns:
+            assigned_parameter (dictionary or None):
+                The content of config[input_parameter], if input_parameter is a key of config
+                and all elements of requested_nested are keys of config[input_parameter], or
+                None otherwise.
+        """
+
+        assigned_parameter = self._assign_parameter(config, input_parameter)
+
+        if assigned_parameter is None:
+            return None
+
+        if not isinstance(assigned_parameter, dict):
+            return None
+
+        if len(requested_nested) == 0:
+            requested_nested = list(assigned_parameter.keys())
+
+        sub_parameters_missing = False
+        for requested_parameter in requested_nested:
+            if requested_parameter not in assigned_parameter.keys():
+                logger.critical(
+                    "ERROR instantiating Configuration: parameter '%s' does not "
+                    "exist in %s" % (requested_parameter, input_parameter)
+                )
+                sub_parameters_missing = True
+
+        if sub_parameters_missing is True:
+            return None
+
+        return assigned_parameter
+
+    def _retrieve_database_credentials(
+        self, config, input_parameter, env_filename, force_config_over_hierarchies
+    ):
+        """This function retrieves the credentials needed to (later) connect to a specific SQL
+        database. If force_config_over_hierarchies is False, it does so hieararchically, by
+        giving top priority to environment variables that are created when running the CI
+        Pipeline, second priority to environment variables that are created locally if a .env
+        file with name env_filename is provided and, finally, by looking at what has been
+        indicated in the input configuration file (read as config).
+
+        When force_config_over_hierarchies is True, it does not matter where the code is
+        running, it will always retrieve the credentials from the configuration file.
+
+        Args:
+            config (dictionary):
+                The configuration file read as a dictionary. It may be an empty dictionary.
+            input_parameter (str):
+                Name of the desired parameter, to be searched for as a primary key of config.
+            env_filename (str):
+                Name of a local .env file that will be run to load environment variables.
+            force_config_over_hierarchies (bool):
+                If True, the contents of the .yml configuration file specified in filepath will
+                take precedence over any other hierarchy (e.g. preference of environment
+                variables if they exist). If False, hierarchies of preference established in
+                this class are applied. This parameter is used for forcing the testing of this
+                class under certain circumstances. Default: False.
+
+        Returns:
+            db_config (dict):
+                Dictionary containing the credentials needed to connect to the desired SQL
+                database. These are:
+                    host (str):
+                        SQL database host address.
+                    dbname (str):
+                        Name of the SQL database.
+                    port (int):
+                        Port where the SQL database can be found.
+                    username (str):
+                        User name to connect to the SQL database.
+                    password (str):
+                        Password associated with username.
+        """
+
+        db_config = self._assign_hierarchical_parameters(config, input_parameter)
+
+        if "port" in config:
+            db_config["port"] = int(db_config["port"])
+
+        if "GDEIMPORTER_DB_HOST" in os.environ and not (force_config_over_hierarchies):
+            # Running the CI pipeline
+            db_config = {
+                "host": os.environ.get("GDEIMPORTER_DB_HOST"),
+                "dbname": os.environ.get("GDEIMPORTER_DB"),
+                "username": os.environ.get("GDEIMPORTER_USER"),
+                "password": os.environ.get("GDEIMPORTER_PASSWORD"),
+                "sourceid": os.environ.get("GDEIMPORTER_SOURCEID"),
+            }
+        elif os.path.isfile(env_filename) and not (force_config_over_hierarchies):
+            # Testing locally with a test database
+            load_dotenv(env_filename)
+            db_config = {
+                "host": os.environ.get("GDEIMPORTER_LOCAL_DB_HOST"),
+                "dbname": os.environ.get("GDEIMPORTER_LOCAL_DB"),
+                "username": os.environ.get("GDEIMPORTER_LOCAL_USER"),
+                "password": os.environ.get("GDEIMPORTER_LOCAL_PASSWORD"),
+                "sourceid": os.environ.get("GDEIMPORTER_LOCAL_SOURCEID"),
+            }
+
+        return db_config

gdeimporter/exposureentity.py

@@ -18,6 +18,7 @@
 
 import logging
 from multiprocessing import Pool
+from functools import partial
 from gdeimporter.tools.data_unit_tiles import DataUnitTilesHelper
 
 
@@ -80,7 +81,9 @@ class ExposureEntity:
         self.name = name
         self.occupancy_cases = {}
 
-    def create_data_unit_tiles(self, occupancy_case, number_cores):
+    def create_data_unit_tiles(
+        self, occupancy_case, number_cores, db_built_up_config, db_table
+    ):
         """This function creates the data-unit tiles associated with all data units of the
         ExposureEntity for a specified 'occupancy_case'. The latter needs to be a key of
         self.occupancy_cases. The data units will be paralellised into as many cores as
@@ -94,6 +97,30 @@ class ExposureEntity:
                 self.occupancy_cases.
             number_cores (int):
                 Number of CPU cores to be used to run this function.
+            db_built_up_config (dict):
+                Dictionary containing the credentials needed to connect to the database where
+                the built-up area values are stored. The keys of the dictionary need to be:
+                    host (str):
+                        SQL database host address.
+                    dbname (str):
+                        Name of the SQL database.
+                    port (int):
+                        Port where the SQL database can be found.
+                    username (str):
+                        User name to connect to the SQL database.
+                    password (str):
+                        Password associated with username.
+                    sourceid (int):
+                        ID of the built-up area source dataset that will be sought for.
+            db_table (str):
+                Name of the table of the SQL database where the built-up area values are stored.
+                It is assumed that this table contains, at least, the following fields:
+                    quadkey (str):
+                        String indicating the quadkey of a tile.
+                    built_area_size (float):
+                        Value of the built-up area to be retrieved.
+                    source_id (int):
+                        ID of the source used to define the built-up area.
 
         Returns:
             This function writes the 'data_unit_tiles' attribute of the data units of the
@@ -113,9 +140,12 @@ class ExposureEntity:
         ]
 
         p = Pool(processes=number_cores)
-        all_data_unit_tiles = p.map(
-            DataUnitTilesHelper.define_data_unit_tiles_and_attributes, data_units_geoms
+        func = partial(
+            DataUnitTilesHelper.define_data_unit_tiles_and_attributes,
+            db_built_up_config,
+            db_table,
         )
+        all_data_unit_tiles = p.map(func, data_units_geoms)
         p.close()
         p.join()
 

gdeimporter/gdeimporter.py

@@ -55,7 +55,10 @@ def main():
         for occupancy_case in config.occupancies_to_run:
             aem.get_data_units(config, exposure_entity_name, occupancy_case)
             aem.exposure_entities[exposure_entity_name].create_data_unit_tiles(
-                occupancy_case, config.number_cores
+                occupancy_case,
+                config.number_cores,
+                config.database_built_up,
+                "obm_built_area_assessments",
             )
 
     print("Name of the model: %s" % (aem.model_name))

gdeimporter/tools/data_unit_tiles.py

@@ -24,6 +24,7 @@ import pyproj
 import mercantile
 import shapely
 from copy import deepcopy
+from gdeimporter.tools.database import Database
 
 logger = logging.getLogger()
 
@@ -100,12 +101,36 @@ class DataUnitTilesHelper:
         return data_unit_tiles, filtered_quadtiles
 
     @staticmethod
-    def define_data_unit_tiles_and_attributes(in_geometry):
+    def define_data_unit_tiles_and_attributes(db_built_up_config, db_table, in_geometry):
         """This function defines the data-unit tiles associated with 'in_geometry' and their
         respective attributes. Data-unit tiles are defined as the intersection between zoom
         level 18 quadtiles and 'in_geometry'.
 
         Args:
+            db_built_up_config (dict):
+                Dictionary containing the credentials needed to connect to the database where
+                the built-up area values are stored. The keys of the dictionary need to be:
+                    host (str):
+                        SQL database host address.
+                    dbname (str):
+                        Name of the SQL database.
+                    port (int):
+                        Port where the SQL database can be found.
+                    username (str):
+                        User name to connect to the SQL database.
+                    password (str):
+                        Password associated with username.
+                    sourceid (int):
+                        ID of the built-up area source dataset that will be sought for.
+            db_table (str):
+                Name of the table of the SQL database where the built-up area values are stored.
+                It is assumed that this table contains, at least, the following fields:
+                    quadkey (str):
+                        String indicating the quadkey of a tile.
+                    built_area_size (float):
+                        Value of the built-up area to be retrieved.
+                    db_source_id (int):
+                        ID of the source used to define the built-up area.
             in_geometry (Shapely Polygon or MultiPolygon):
                 Geometry for which the associated data-unit tiles will be defined.
 
@@ -164,7 +189,9 @@ class DataUnitTilesHelper:
         # Write values to 'data_unit_tiles'
         data_unit_tiles["size_data_unit_tile_area"] = all_areas
         data_unit_tiles["size_data_unit_tile_built_up_area"] = (
-            DataUnitTilesHelper.retrieve_built_up_area(data_unit_tiles["quadkey"].values)
+            DataUnitTilesHelper.retrieve_built_up_area(
+                data_unit_tiles["quadkey"].values, db_built_up_config, db_table
+            )
             * all_fractions
         )
         data_unit_tiles["fraction_data_unit_area"] = all_areas / all_areas.sum()
@@ -463,14 +490,72 @@ class DataUnitTilesHelper:
         return geometry.area
 
     @staticmethod
-    def retrieve_built_up_area(quadkeys):
-        """This function retrieves the built-up area associated with the input 'quadkeys' from the
-        OBM Tiles database.
+    def retrieve_built_up_area(quadkeys, db_built_up_config, db_table):
+        """This function retrieves the built-up area associated with the input quadkeys from
+        the OBM Tiles database.
 
-        ================== TO BE IMPLEMENTED ==================
+        Args:
+            quadkeys (array of str):
+                Quadkeys for which the built-up areas will be retrieved.
+            db_built_up_config (dict):
+                Dictionary containing the credentials needed to connect to the database where
+                the built-up area values are stored. The keys of the dictionary need to be:
+                    host (str):
+                        SQL database host address.
+                    dbname (str):
+                        Name of the SQL database.
+                    port (int):
+                        Port where the SQL database can be found.
+                    username (str):
+                        User name to connect to the SQL database.
+                    password (str):
+                        Password associated with username.
+                    sourceid (int):
+                        ID of the built-up area source dataset that will be sought for.
+                 It is assumed that the database contains a table with name db_table.
+            db_table (str):
+                Name of the table of the SQL database where the built-up area values are stored.
+                It is assumed that this table contains, at least, the following fields:
+                    quadkey (str):
+                        String indicating the quadkey of a tile.
+                    built_area_size (float):
+                        Value of the built-up area to be retrieved.
+                    source_id (int):
+                        ID of the source used to define the built-up area.
 
         Returns:
-            Array of floats with the built-up area values associated with the 'quadkeys'.
+            built_up_areas (array of float):
+                Built-up area values associated with the quadkeys.
         """
 
-        return numpy.ones([len(quadkeys)])
+        built_up_areas = numpy.zeros([len(quadkeys)], dtype=float)
+
+        # Create Database instance and establish the connection and cursor
+        db_built_up_areas = Database(**db_built_up_config)
+        db_built_up_areas.create_connection_and_cursor()
+
+        for i, quadkey in enumerate(quadkeys):
+            # Query the database
+            sql_query = (
+                "SELECT built_area_size FROM %s WHERE (quadkey='%s' AND source_id=%s);"
+                % (db_table, quadkey, db_built_up_config["sourceid"])
+            )
+            db_built_up_areas.cursor.execute(sql_query)
+            exec_result = db_built_up_areas.cursor.fetchall()
+
+            # Interpret the output of the query
+            if len(exec_result) == 0:  # If the quadkey is not found the built-up area is zero
+                built_up_areas[i] = 0.0
+            elif len(exec_result) == 1:
+                built_up_areas[i] = exec_result[0][0]
+            else:  # More than one entries found, this is an error
+                logger.error(
+                    "ERROR IN get_ghs_built_up_area_from_obm_tiles: "
+                    "MORE THAN ONE ENTRY FOUND FOR CELL ID %s" % (quadkey)
+                )
+                built_up_areas[i] = numpy.nan
+
+        # Close connection to database
+        db_built_up_areas.close_connection()
+
+        return built_up_areas

gdeimporter/tools/database.py

+#!/usr/bin/env python3
+
+# Copyright (C) 2021:
+#   Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum GFZ
+#
+# This program is free software: you can redistribute it and/or modify it
+# under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or (at
+# your option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero
+# General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program. If not, see http://www.gnu.org/licenses/.
+
+import logging
+import psycopg2
+
+logger = logging.getLogger()
+
+
+class Database:
+    """This class contains the credentials needed to connect to a given SQL database.
+
+    Attributes:
+        self.host (str):
+            SQL database host address.
+        self.dbname (str):
+            Name of the SQL database.
+        self.port (int):
+            Port where the SQL database can be found.
+        self.username (str):
+            User name to connect to the SQL database.
+        self.password (str):
+            Password associated with self.username.
+        self.connection (psycopg2.extensions.connection):
+            Object that handles the connection to the SQL database.
+        self.cursor (psycopg2.extensions.cursor):
+            Cursor object that allows to execute commands on the SQL database.
+    """
+
+    def __init__(self, dbname, username, password, host, port=5432, **kwargs):
+        """This function initialises the class.
+
+        Args:
+            host (str):
+                SQL database host address.
+            dbname (str):
+                Name of the SQL database.
+            port (int):
+                Port where the SQL database can be found.
+            username (str):
+                User name to connect to the SQL database.
+            password (str):
+                Password associated with self.username.
+        """
+
+        self.host = host
+        self.dbname = dbname
+        self.port = port
+        self.username = username
+        self.password = password
+
+        # Initialise other attributes
+        self.connection = None
+        self.cursor = None
+
+    def create_connection_and_cursor(self):
+        """Create a database connection and a cursor with the given credentials and store the
+        connection and cursor as new attributes.
+
+        Returns:
+            self.connection and self.cursor are updated.
+        """
+
+        connection_string = "host={} dbname={} user={} password={} port={}".format(
+            self.host, self.dbname, self.username, self.password, self.port
+        )
+
+        connection = psycopg2.connect(connection_string)
+        connection.set_session(autocommit=True)
+        self.connection = connection
+        self.cursor = connection.cursor()
+
+    def close_connection(self):
+        """Close the connection to the database."""
+
+        self.connection.close()

setup.py

@@ -38,6 +38,8 @@ setup(
         "mercantile",
         "pyproj",
         "shapely",
+        "psycopg2-binary",
+        "python-dotenv",
     ],
     extras_require={
         "tests": tests_require,

tests/conftest.py

+#!/usr/bin/env python3
+
+# Copyright (C) 2021:
+#   Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum GFZ
+#
+# This program is free software: you can redistribute it and/or modify it
+# under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or (at
+# your option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero
+# General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program. If not, see http://www.gnu.org/licenses/.
+
+import os
+import pytest
+from dotenv import load_dotenv
+from pathlib import Path
+from gdeimporter.tools.database import Database
+
+load_dotenv(Path(".env").resolve())
+
+
+@pytest.fixture
+def built_up_area_test_db():
+    """A test database simulating to be obm_built_area_assessments."""
+
+    init_built_up_db()
+    return
+
+
+def init_built_up_db():
+    """Populates the test database that simulates to be obm_built_area_assessments with a basic
+    schema and data.
+    """
+
+    if "GDEIMPORTER_DB_HOST" in os.environ:  # When running the CI pipeline
+        db_built_up_config = {
+            "host": os.environ.get("GDEIMPORTER_DB_HOST"),
+            "dbname": os.environ.get("GDEIMPORTER_DB"),
+            "port": "",
+            "username": os.environ.get("GDEIMPORTER_USER"),
+            "password": os.environ.get("GDEIMPORTER_PASSWORD"),
+        }
+
+        # Create Database instance and establish the connection and cursor
+        db = Database(**db_built_up_config)
+        db.create_connection_and_cursor()
+
+        # Create columns and populate the test database
+        with open("tests/data/test_database_built_up.sql", "r") as file:
+            for command in file.read().split(";"):
+                if command != "\n":
+                    db.cursor.execute(command)
+
+        db.close_connection()

tests/data/config_for_testing_cores_not_integer.yml

@@ -5,3 +5,8 @@ boundaries_pathname: /some/path/to/directory
 occupancies_to_run: residential, commercial, industrial
 exposure_entities_to_run: all
 number_cores: some
+database_built_up:
+  host: host.somewhere.xx
+  dbname: some_database_name
+  username: some_username
+  password: some_password

tests/data/config_for_testing_db_built_up_not_dict.yml

+model_name: esrm20