def load_shapefile(self, feature_type, base_path):
        """Load downloaded shape file to QGIS Main Window.

        :param feature_type: What kind of features should be downloaded.
            Currently 'buildings', 'building-points' or 'roads' are supported.
        :type feature_type: str

        :param base_path: The base path of the shape file (without extension).
        :type base_path: str

        :raises: FileMissingError - when buildings.shp not exist
        """

        path = '%s.shp' % base_path

        if not os.path.exists(path):
            message = self.tr(
                '%s does not exist. The server does not have any data for '
                'this extent.' % path)
            raise FileMissingError(message)

        layer = self.iface.addVectorLayer(path, feature_type, 'ogr')

        # Check if it's a building layer about the 2.5D
        if feature_type == 'buildings':
            layer_scope = QgsExpressionContextUtils.layerScope(layer)
            if not layer_scope.variable('qgis_25d_height'):
                QgsExpressionContextUtils.setLayerVariable(
                    layer, 'qgis_25d_height', 0.0002)
            if not layer_scope.variable('qgis_25d_angle'):
                QgsExpressionContextUtils.setLayerVariable(
                    layer, 'qgis_25d_angle', 70)
Load downloaded shape file to QGIS Main Window.

        :param feature_type: What kind of features should be downloaded.
            Currently 'buildings', 'building-points' or 'roads' are supported.
        :type feature_type: str

        :param base_path: The base path of the shape file (without extension).
        :type base_path: str

        :raises: FileMissingError - when buildings.shp not exist