Exemplo n.º 1
0
    def test_clip_raster(self):
        """Test clip_raster work"""
        new_raster = clip_raster(self.raster, self.raster.width(),
                                 self.raster.height(), self.extent)

        self.assertEqual(self.raster.rasterUnitsPerPixelY(),
                         new_raster.rasterUnitsPerPixelY())
        self.assertEqual(self.raster.rasterUnitsPerPixelX(),
                         new_raster.rasterUnitsPerPixelX())
        self.assertEqual(self.raster.extent(), new_raster.extent())
        self.assertEqual(self.raster.width(), new_raster.width())
        self.assertEqual(self.raster.height(), new_raster.height())

        # Set extent as 1/2 of self.extent
        center = self.extent.center()
        x_max, y_max = center.x(), center.y()
        new_extent = QgsRectangle(self.extent.xMinimum(),
                                  self.extent.yMinimum(), x_max, y_max)
        new_raster = clip_raster(self.raster, self.raster.width(),
                                 self.raster.height(), new_extent)
        self.assertAlmostEquals(self.raster.rasterUnitsPerPixelY(),
                                2 * new_raster.rasterUnitsPerPixelY())
        self.assertAlmostEquals(self.raster.rasterUnitsPerPixelX(),
                                2 * new_raster.rasterUnitsPerPixelX())
        self.assertEqual(new_extent, new_raster.extent())
        self.assertEqual(self.raster.width(), new_raster.width())
        self.assertEqual(self.raster.height(), new_raster.height())
    def test_clip_raster(self):
        """Test clip_raster work"""
        new_raster = clip_raster(
            self.raster,
            self.raster.width(),
            self.raster.height(),
            self.extent
        )

        self.assertEqual(self.raster.rasterUnitsPerPixelY(),
                         new_raster.rasterUnitsPerPixelY())
        self.assertEqual(self.raster.rasterUnitsPerPixelX(),
                         new_raster.rasterUnitsPerPixelX())
        self.assertEqual(self.raster.extent(),
                         new_raster.extent())
        self.assertEqual(self.raster.width(),
                         new_raster.width())
        self.assertEqual(self.raster.height(),
                         new_raster.height())

        # Set extent as 1/2 of self.extent
        center = self.extent.center()
        x_max, y_max = center.x(), center.y()
        new_extent = QgsRectangle(
            self.extent.xMinimum(),
            self.extent.yMinimum(),
            x_max,
            y_max
        )
        new_raster = clip_raster(
            self.raster,
            self.raster.width(),
            self.raster.height(),
            new_extent
        )
        self.assertAlmostEquals(
            self.raster.rasterUnitsPerPixelY(),
            2 * new_raster.rasterUnitsPerPixelY())
        self.assertAlmostEquals(
            self.raster.rasterUnitsPerPixelX(),
            2 * new_raster.rasterUnitsPerPixelX())
        self.assertEqual(new_extent, new_raster.extent())
        self.assertEqual(self.raster.width(), new_raster.width())
        self.assertEqual(self.raster.height(), new_raster.height())
Exemplo n.º 3
0
    def run(self, layers=None):
        """Run the impact function.

        :param layers: List of layers expected to contain at least:
            H: Polygon layer of inundation areas
            E: Vector layer of roads
        :type layers: list

        :returns: A new line layer with inundated roads marked.
        :type: safe_layer
        """
        self.validate()
        self.prepare(layers)

        target_field = self.target_field
        road_type_field = self.parameters['road_type_field']
        threshold_min = self.parameters['min threshold [m]']
        threshold_max = self.parameters['max threshold [m]']

        if threshold_min > threshold_max:
            message = tr(
                'The minimal threshold is greater then the maximal specified '
                'threshold. Please check the values.')
            raise GetDataError(message)

        # Extract data
        H = self.hazard  # Flood
        E = self.exposure  # Roads

        H = H.get_layer()
        E = E.get_layer()

        # reproject self.extent to the hazard projection
        hazard_crs = H.crs()
        hazard_authid = hazard_crs.authid()

        if hazard_authid == 'EPSG:4326':
            viewport_extent = self.requested_extent
        else:
            geo_crs = QgsCoordinateReferenceSystem()
            geo_crs.createFromSrid(4326)
            viewport_extent = extent_to_geo_array(
                QgsRectangle(*self.requested_extent), geo_crs, hazard_crs)

        # Align raster extent and viewport
        # assuming they are both in the same projection
        raster_extent = H.dataProvider().extent()
        clip_xmin = raster_extent.xMinimum()
        # clip_xmax = raster_extent.xMaximum()
        clip_ymin = raster_extent.yMinimum()
        # clip_ymax = raster_extent.yMaximum()
        if viewport_extent[0] > clip_xmin:
            clip_xmin = viewport_extent[0]
        if viewport_extent[1] > clip_ymin:
            clip_ymin = viewport_extent[1]
        # TODO: Why have these two clauses when they are not used?
        # Commenting out for now.
        # if viewport_extent[2] < clip_xmax:
        #     clip_xmax = viewport_extent[2]
        # if viewport_extent[3] < clip_ymax:
        #     clip_ymax = viewport_extent[3]

        height = ((viewport_extent[3] - viewport_extent[1]) /
                  H.rasterUnitsPerPixelY())
        height = int(height)
        width = ((viewport_extent[2] - viewport_extent[0]) /
                 H.rasterUnitsPerPixelX())
        width = int(width)

        raster_extent = H.dataProvider().extent()
        xmin = raster_extent.xMinimum()
        xmax = raster_extent.xMaximum()
        ymin = raster_extent.yMinimum()
        ymax = raster_extent.yMaximum()

        x_delta = (xmax - xmin) / H.width()
        x = xmin
        for i in range(H.width()):
            if abs(x - clip_xmin) < x_delta:
                # We have found the aligned raster boundary
                break
            x += x_delta
            _ = i

        y_delta = (ymax - ymin) / H.height()
        y = ymin
        for i in range(H.width()):
            if abs(y - clip_ymin) < y_delta:
                # We have found the aligned raster boundary
                break
            y += y_delta
        clip_extent = [x, y, x + width * x_delta, y + height * y_delta]

        # Clip and polygonize
        small_raster = clip_raster(H, width, height,
                                   QgsRectangle(*clip_extent))
        (flooded_polygon_inside,
         flooded_polygon_outside) = polygonize_gdal(small_raster,
                                                    threshold_min,
                                                    threshold_max)

        # Filter geometry and data using the extent
        extent = QgsRectangle(*self.requested_extent)
        request = QgsFeatureRequest()
        request.setFilterRect(extent)

        if flooded_polygon_inside is None:
            message = tr(
                'There are no objects in the hazard layer with "value">%s.'
                'Please check the value or use other extent.' %
                (threshold_min, ))
            raise GetDataError(message)

        # reproject the flood polygons to exposure projection
        exposure_crs = E.crs()
        exposure_authid = exposure_crs.authid()

        if hazard_authid != exposure_authid:
            flooded_polygon_inside = reproject_vector_layer(
                flooded_polygon_inside, E.crs())
            flooded_polygon_outside = reproject_vector_layer(
                flooded_polygon_outside, E.crs())

        # Clip exposure by the extent
        # extent_as_polygon = QgsGeometry().fromRect(extent)
        # no need to clip since It is using a bbox request
        # line_layer = clip_by_polygon(
        #    E,
        #    extent_as_polygon
        # )
        # Find inundated roads, mark them
        line_layer = split_by_polygon_in_out(E, flooded_polygon_inside,
                                             flooded_polygon_outside,
                                             target_field, 1, request)

        target_field_index = line_layer.dataProvider().\
            fieldNameIndex(target_field)

        # Generate simple impact report
        epsg = get_utm_epsg(self.requested_extent[0], self.requested_extent[1])
        output_crs = QgsCoordinateReferenceSystem(epsg)
        transform = QgsCoordinateTransform(E.crs(), output_crs)
        road_len = flooded_len = 0  # Length of roads
        roads_by_type = dict()  # Length of flooded roads by types

        roads_data = line_layer.getFeatures()
        road_type_field_index = line_layer.fieldNameIndex(road_type_field)
        for road in roads_data:
            attributes = road.attributes()
            road_type = attributes[road_type_field_index]
            if road_type.__class__.__name__ == 'QPyNullVariant':
                road_type = tr('Other')
            geom = road.geometry()
            geom.transform(transform)
            length = geom.length()
            road_len += length

            if road_type not in roads_by_type:
                roads_by_type[road_type] = {'flooded': 0, 'total': 0}
            roads_by_type[road_type]['total'] += length

            if attributes[target_field_index] == 1:
                flooded_len += length
                roads_by_type[road_type]['flooded'] += length

        table_body = self._tabulate(flooded_len, self.question, road_len,
                                    roads_by_type)

        impact_summary = Table(table_body).toNewlineFreeString()
        map_title = tr('Roads inundated')

        style_classes = [
            dict(label=tr('Not Inundated'),
                 value=0,
                 colour='#1EFC7C',
                 transparency=0,
                 size=0.5),
            dict(label=tr('Inundated'),
                 value=1,
                 colour='#F31A1C',
                 transparency=0,
                 size=0.5)
        ]
        style_info = dict(target_field=target_field,
                          style_classes=style_classes,
                          style_type='categorizedSymbol')

        # Convert QgsVectorLayer to inasafe layer and return it
        line_layer = Vector(data=line_layer,
                            name=tr('Flooded roads'),
                            keywords={
                                'impact_summary': impact_summary,
                                'map_title': map_title,
                                'target_field': target_field
                            },
                            style_info=style_info)
        self._impact = line_layer
        return line_layer
Exemplo n.º 4
0
    def run(self):
        """Run the impact function.

        :returns: A new line layer with inundated roads marked.
        :type: safe_layer
        """
        self.validate()
        self.prepare()

        target_field = self.target_field
        # Get parameters from layer's keywords
        road_class_field = self.exposure.keyword('road_class_field')
        # Get parameters from IF parameter
        threshold_min = self.parameters['min threshold'].value
        threshold_max = self.parameters['max threshold'].value

        if threshold_min > threshold_max:
            message = tr(
                'The minimal threshold is greater than the maximal specified '
                'threshold. Please check the values.')
            raise GetDataError(message)

        # reproject self.extent to the hazard projection
        hazard_crs = self.hazard.layer.crs()
        hazard_authid = hazard_crs.authid()

        if hazard_authid == 'EPSG:4326':
            viewport_extent = self.requested_extent
        else:
            geo_crs = QgsCoordinateReferenceSystem()
            geo_crs.createFromSrid(4326)
            viewport_extent = extent_to_geo_array(
                QgsRectangle(*self.requested_extent), geo_crs, hazard_crs)

        # Align raster extent and viewport
        # assuming they are both in the same projection
        raster_extent = self.hazard.layer.dataProvider().extent()
        clip_xmin = raster_extent.xMinimum()
        # clip_xmax = raster_extent.xMaximum()
        clip_ymin = raster_extent.yMinimum()
        # clip_ymax = raster_extent.yMaximum()
        if viewport_extent[0] > clip_xmin:
            clip_xmin = viewport_extent[0]
        if viewport_extent[1] > clip_ymin:
            clip_ymin = viewport_extent[1]
        # TODO: Why have these two clauses when they are not used?
        # Commenting out for now.
        # if viewport_extent[2] < clip_xmax:
        #     clip_xmax = viewport_extent[2]
        # if viewport_extent[3] < clip_ymax:
        #     clip_ymax = viewport_extent[3]

        height = ((viewport_extent[3] - viewport_extent[1]) /
                  self.hazard.layer.rasterUnitsPerPixelY())
        height = int(height)
        width = ((viewport_extent[2] - viewport_extent[0]) /
                 self.hazard.layer.rasterUnitsPerPixelX())
        width = int(width)

        raster_extent = self.hazard.layer.dataProvider().extent()
        xmin = raster_extent.xMinimum()
        xmax = raster_extent.xMaximum()
        ymin = raster_extent.yMinimum()
        ymax = raster_extent.yMaximum()

        x_delta = (xmax - xmin) / self.hazard.layer.width()
        x = xmin
        for i in range(self.hazard.layer.width()):
            if abs(x - clip_xmin) < x_delta:
                # We have found the aligned raster boundary
                break
            x += x_delta
            _ = i

        y_delta = (ymax - ymin) / self.hazard.layer.height()
        y = ymin
        for i in range(self.hazard.layer.width()):
            if abs(y - clip_ymin) < y_delta:
                # We have found the aligned raster boundary
                break
            y += y_delta
        clip_extent = [x, y, x + width * x_delta, y + height * y_delta]

        # Clip hazard raster
        small_raster = clip_raster(self.hazard.layer, width, height,
                                   QgsRectangle(*clip_extent))

        # Create vector features from the flood raster
        # For each raster cell there is one rectangular polygon
        # Data also get spatially indexed for faster operation
        index, flood_cells_map = _raster_to_vector_cells(
            small_raster, threshold_min, threshold_max,
            self.exposure.layer.crs())

        # Filter geometry and data using the extent
        ct = QgsCoordinateTransform(QgsCoordinateReferenceSystem("EPSG:4326"),
                                    self.exposure.layer.crs())
        extent = ct.transformBoundingBox(QgsRectangle(*self.requested_extent))
        request = QgsFeatureRequest()
        request.setFilterRect(extent)

        if len(flood_cells_map) == 0:
            message = tr(
                'There are no objects in the hazard layer with "value" > %s. '
                'Please check the value or use other extent.' %
                (threshold_min, ))
            raise GetDataError(message)

        # create template for the output layer
        line_layer_tmp = create_layer(self.exposure.layer)
        new_field = QgsField(target_field, QVariant.Int)
        line_layer_tmp.dataProvider().addAttributes([new_field])
        line_layer_tmp.updateFields()

        # create empty output layer and load it
        filename = unique_filename(suffix='.shp')
        QgsVectorFileWriter.writeAsVectorFormat(line_layer_tmp, filename,
                                                "utf-8", None,
                                                "ESRI Shapefile")
        line_layer = QgsVectorLayer(filename, "flooded roads", "ogr")

        # Do the heavy work - for each road get flood polygon for that area and
        # do the intersection/difference to find out which parts are flooded
        _intersect_lines_with_vector_cells(self.exposure.layer, request, index,
                                           flood_cells_map, line_layer,
                                           target_field)

        target_field_index = line_layer.dataProvider().\
            fieldNameIndex(target_field)

        # Generate simple impact report
        epsg = get_utm_epsg(self.requested_extent[0], self.requested_extent[1])
        output_crs = QgsCoordinateReferenceSystem(epsg)
        transform = QgsCoordinateTransform(self.exposure.layer.crs(),
                                           output_crs)
        flooded_keyword = tr('Flooded in the threshold (m)')
        self.affected_road_categories = [flooded_keyword]
        self.affected_road_lengths = OrderedDict([(flooded_keyword, {})])
        self.road_lengths = OrderedDict()

        if line_layer.featureCount() < 1:
            raise ZeroImpactException()

        roads_data = line_layer.getFeatures()
        road_type_field_index = line_layer.fieldNameIndex(road_class_field)
        for road in roads_data:
            attributes = road.attributes()
            road_type = attributes[road_type_field_index]
            if road_type.__class__.__name__ == 'QPyNullVariant':
                road_type = tr('Other')
            geom = road.geometry()
            geom.transform(transform)
            length = geom.length()

            if road_type not in self.road_lengths:
                self.affected_road_lengths[flooded_keyword][road_type] = 0
                self.road_lengths[road_type] = 0

            self.road_lengths[road_type] += length
            if attributes[target_field_index] == 1:
                self.affected_road_lengths[flooded_keyword][
                    road_type] += length

        impact_summary = self.html_report()

        # For printing map purpose
        map_title = tr('Roads inundated')
        legend_title = tr('Road inundated status')

        style_classes = [
            dict(label=tr('Not Inundated'),
                 value=0,
                 colour='#1EFC7C',
                 transparency=0,
                 size=0.5),
            dict(label=tr('Inundated'),
                 value=1,
                 colour='#F31A1C',
                 transparency=0,
                 size=0.5)
        ]
        style_info = dict(target_field=target_field,
                          style_classes=style_classes,
                          style_type='categorizedSymbol')

        # Convert QgsVectorLayer to inasafe layer and return it
        line_layer = Vector(data=line_layer,
                            name=tr('Flooded roads'),
                            keywords={
                                'impact_summary': impact_summary,
                                'map_title': map_title,
                                'legend_title': legend_title,
                                'target_field': target_field
                            },
                            style_info=style_info)
        self._impact = line_layer
        return line_layer
Exemplo n.º 5
0
    def run(self, layers=None):
        """Run the impact function.

        :param layers: List of layers expected to contain at least:
            H: Polygon layer of inundation areas
            E: Vector layer of roads
        :type layers: list

        :returns: A new line layer with inundated roads marked.
        :type: safe_layer
        """
        self.validate()
        self.prepare(layers)

        target_field = self.target_field
        road_type_field = self.parameters['road_type_field']
        threshold_min = self.parameters['min threshold [m]']
        threshold_max = self.parameters['max threshold [m]']

        if threshold_min > threshold_max:
            message = tr(
                'The minimal threshold is greater then the maximal specified '
                'threshold. Please check the values.')
            raise GetDataError(message)

        # Extract data
        H = self.hazard    # Flood
        E = self.exposure  # Roads

        H = H.get_layer()
        E = E.get_layer()

        # reproject self.extent to the hazard projection
        hazard_crs = H.crs()
        hazard_authid = hazard_crs.authid()

        if hazard_authid == 'EPSG:4326':
            viewport_extent = self.requested_extent
        else:
            geo_crs = QgsCoordinateReferenceSystem()
            geo_crs.createFromSrid(4326)
            viewport_extent = extent_to_geo_array(
                QgsRectangle(*self.requested_extent), geo_crs, hazard_crs)

        # Align raster extent and viewport
        # assuming they are both in the same projection
        raster_extent = H.dataProvider().extent()
        clip_xmin = raster_extent.xMinimum()
        # clip_xmax = raster_extent.xMaximum()
        clip_ymin = raster_extent.yMinimum()
        # clip_ymax = raster_extent.yMaximum()
        if viewport_extent[0] > clip_xmin:
            clip_xmin = viewport_extent[0]
        if viewport_extent[1] > clip_ymin:
            clip_ymin = viewport_extent[1]
        # TODO: Why have these two clauses when they are not used?
        # Commenting out for now.
        # if viewport_extent[2] < clip_xmax:
        #     clip_xmax = viewport_extent[2]
        # if viewport_extent[3] < clip_ymax:
        #     clip_ymax = viewport_extent[3]

        height = ((viewport_extent[3] - viewport_extent[1]) /
                  H.rasterUnitsPerPixelY())
        height = int(height)
        width = ((viewport_extent[2] - viewport_extent[0]) /
                 H.rasterUnitsPerPixelX())
        width = int(width)

        raster_extent = H.dataProvider().extent()
        xmin = raster_extent.xMinimum()
        xmax = raster_extent.xMaximum()
        ymin = raster_extent.yMinimum()
        ymax = raster_extent.yMaximum()

        x_delta = (xmax - xmin) / H.width()
        x = xmin
        for i in range(H.width()):
            if abs(x - clip_xmin) < x_delta:
                # We have found the aligned raster boundary
                break
            x += x_delta
            _ = i

        y_delta = (ymax - ymin) / H.height()
        y = ymin
        for i in range(H.width()):
            if abs(y - clip_ymin) < y_delta:
                # We have found the aligned raster boundary
                break
            y += y_delta
        clip_extent = [x, y, x + width * x_delta, y + height * y_delta]

        # Clip and polygonize
        small_raster = clip_raster(
            H, width, height, QgsRectangle(*clip_extent))
        (flooded_polygon_inside, flooded_polygon_outside) = polygonize_gdal(
            small_raster, threshold_min, threshold_max)

        # Filter geometry and data using the extent
        extent = QgsRectangle(*self.requested_extent)
        request = QgsFeatureRequest()
        request.setFilterRect(extent)

        if flooded_polygon_inside is None:
            message = tr(
                'There are no objects in the hazard layer with "value">%s.'
                'Please check the value or use other extent.' % (
                    threshold_min, ))
            raise GetDataError(message)

        # reproject the flood polygons to exposure projection
        exposure_crs = E.crs()
        exposure_authid = exposure_crs.authid()

        if hazard_authid != exposure_authid:
            flooded_polygon_inside = reproject_vector_layer(
                flooded_polygon_inside, E.crs())
            flooded_polygon_outside = reproject_vector_layer(
                flooded_polygon_outside, E.crs())

        # Clip exposure by the extent
        # extent_as_polygon = QgsGeometry().fromRect(extent)
        # no need to clip since It is using a bbox request
        # line_layer = clip_by_polygon(
        #    E,
        #    extent_as_polygon
        # )
        # Find inundated roads, mark them
        line_layer = split_by_polygon_in_out(
            E,
            flooded_polygon_inside,
            flooded_polygon_outside,
            target_field, 1, request)

        target_field_index = line_layer.dataProvider().\
            fieldNameIndex(target_field)

        # Generate simple impact report
        epsg = get_utm_epsg(self.requested_extent[0], self.requested_extent[1])
        output_crs = QgsCoordinateReferenceSystem(epsg)
        transform = QgsCoordinateTransform(E.crs(), output_crs)
        road_len = flooded_len = 0  # Length of roads
        roads_by_type = dict()      # Length of flooded roads by types

        roads_data = line_layer.getFeatures()
        road_type_field_index = line_layer.fieldNameIndex(road_type_field)
        for road in roads_data:
            attributes = road.attributes()
            road_type = attributes[road_type_field_index]
            if road_type.__class__.__name__ == 'QPyNullVariant':
                road_type = tr('Other')
            geom = road.geometry()
            geom.transform(transform)
            length = geom.length()
            road_len += length

            if road_type not in roads_by_type:
                roads_by_type[road_type] = {'flooded': 0, 'total': 0}
            roads_by_type[road_type]['total'] += length

            if attributes[target_field_index] == 1:
                flooded_len += length
                roads_by_type[road_type]['flooded'] += length

        table_body = self._tabulate(flooded_len, self.question, road_len,
                                    roads_by_type)

        impact_summary = Table(table_body).toNewlineFreeString()
        map_title = tr('Roads inundated')

        style_classes = [
            dict(
                label=tr('Not Inundated'), value=0,
                colour='#1EFC7C', transparency=0, size=0.5),
            dict(
                label=tr('Inundated'), value=1,
                colour='#F31A1C', transparency=0, size=0.5)]
        style_info = dict(
            target_field=target_field,
            style_classes=style_classes,
            style_type='categorizedSymbol')

        # Convert QgsVectorLayer to inasafe layer and return it
        line_layer = Vector(
            data=line_layer,
            name=tr('Flooded roads'),
            keywords={
                'impact_summary': impact_summary,
                'map_title': map_title,
                'target_field': target_field},
            style_info=style_info)
        self._impact = line_layer
        return line_layer
Exemplo n.º 6
0
    def run(self):
        """Run the impact function.

        :returns: A new line layer with inundated roads marked.
        :type: safe_layer
        """
        self.validate()
        self.prepare()

        self.provenance.append_step(
            'Calculating Step', 'Impact function is calculating the impact.')

        # Thresholds for tsunami hazard zone breakdown.
        low_max = self.parameters['low_threshold'].value
        medium_max = self.parameters['medium_threshold'].value
        high_max = self.parameters['high_threshold'].value

        target_field = self.target_field
        # Get parameters from layer's keywords
        road_class_field = self.exposure.keyword('road_class_field')

        # reproject self.extent to the hazard projection
        hazard_crs = self.hazard.layer.crs()
        hazard_authid = hazard_crs.authid()

        if hazard_authid == 'EPSG:4326':
            viewport_extent = self.requested_extent
        else:
            geo_crs = QgsCoordinateReferenceSystem()
            geo_crs.createFromSrid(4326)
            viewport_extent = extent_to_geo_array(
                QgsRectangle(*self.requested_extent), geo_crs, hazard_crs)

        # Align raster extent and viewport
        # assuming they are both in the same projection
        raster_extent = self.hazard.layer.dataProvider().extent()
        clip_xmin = raster_extent.xMinimum()
        # clip_xmax = raster_extent.xMaximum()
        clip_ymin = raster_extent.yMinimum()
        # clip_ymax = raster_extent.yMaximum()
        if viewport_extent[0] > clip_xmin:
            clip_xmin = viewport_extent[0]
        if viewport_extent[1] > clip_ymin:
            clip_ymin = viewport_extent[1]

        height = ((viewport_extent[3] - viewport_extent[1]) /
                  self.hazard.layer.rasterUnitsPerPixelY())
        height = int(height)
        width = ((viewport_extent[2] - viewport_extent[0]) /
                 self.hazard.layer.rasterUnitsPerPixelX())
        width = int(width)

        raster_extent = self.hazard.layer.dataProvider().extent()
        xmin = raster_extent.xMinimum()
        xmax = raster_extent.xMaximum()
        ymin = raster_extent.yMinimum()
        ymax = raster_extent.yMaximum()

        x_delta = (xmax - xmin) / self.hazard.layer.width()
        x = xmin
        for i in range(self.hazard.layer.width()):
            if abs(x - clip_xmin) < x_delta:
                # We have found the aligned raster boundary
                break
            x += x_delta
            _ = i

        y_delta = (ymax - ymin) / self.hazard.layer.height()
        y = ymin
        for i in range(self.hazard.layer.width()):
            if abs(y - clip_ymin) < y_delta:
                # We have found the aligned raster boundary
                break
            y += y_delta
        clip_extent = [x, y, x + width * x_delta, y + height * y_delta]

        # Clip hazard raster
        small_raster = clip_raster(self.hazard.layer, width, height,
                                   QgsRectangle(*clip_extent))

        # Create vector features from the flood raster
        # For each raster cell there is one rectangular polygon
        # Data also get spatially indexed for faster operation
        ranges = OrderedDict()
        ranges[0] = [0.0, 0.0]
        ranges[1] = [0.0, low_max]
        ranges[2] = [low_max, medium_max]
        ranges[3] = [medium_max, high_max]
        ranges[4] = [high_max, None]

        index, flood_cells_map = _raster_to_vector_cells(
            small_raster, ranges, self.exposure.layer.crs())

        # Filter geometry and data using the extent
        ct = QgsCoordinateTransform(QgsCoordinateReferenceSystem("EPSG:4326"),
                                    self.exposure.layer.crs())
        extent = ct.transformBoundingBox(QgsRectangle(*self.requested_extent))
        request = QgsFeatureRequest()
        request.setFilterRect(extent)
        """
        if len(low_max_flood_cells_map) == 0 and \
            len(medium_max_flood_cells_map) == 0 and \
            len(high_max_flood_cells_map) == 0 and \
            len(high_min_flood_cells_map) == 0:
            message = tr(
                'There are no objects in the hazard layer with "value" > 0. '
                'Please check the value or use other extent.' % (
                    threshold_min, ))
            raise GetDataError(message)
        """

        # create template for the output layer
        line_layer_tmp = create_layer(self.exposure.layer)
        new_field = QgsField(target_field, QVariant.Int)
        line_layer_tmp.dataProvider().addAttributes([new_field])
        line_layer_tmp.updateFields()

        # create empty output layer and load it
        filename = unique_filename(suffix='.shp')
        QgsVectorFileWriter.writeAsVectorFormat(line_layer_tmp, filename,
                                                "utf-8", None,
                                                "ESRI Shapefile")
        line_layer = QgsVectorLayer(filename, "flooded roads", "ogr")

        # Do the heavy work - for each road get flood polygon for that area and
        # do the intersection/difference to find out which parts are flooded
        _intersect_lines_with_vector_cells(self.exposure.layer, request, index,
                                           flood_cells_map, line_layer,
                                           target_field)

        target_field_index = line_layer.dataProvider().\
            fieldNameIndex(target_field)

        # Generate simple impact report
        epsg = get_utm_epsg(self.requested_extent[0], self.requested_extent[1])
        output_crs = QgsCoordinateReferenceSystem(epsg)
        transform = QgsCoordinateTransform(self.exposure.layer.crs(),
                                           output_crs)

        # Roads breakdown
        self.road_lengths = OrderedDict()
        self.affected_road_categories = self.hazard_classes
        # Impacted roads breakdown
        self.affected_road_lengths = OrderedDict([
            (self.hazard_classes[0], {}),
            (self.hazard_classes[1], {}),
            (self.hazard_classes[2], {}),
            (self.hazard_classes[3], {}),
            (self.hazard_classes[4], {}),
        ])

        if line_layer.featureCount() < 1:
            raise ZeroImpactException()

        roads_data = line_layer.getFeatures()
        road_type_field_index = line_layer.fieldNameIndex(road_class_field)
        for road in roads_data:
            attributes = road.attributes()
            affected = attributes[target_field_index]
            hazard_zone = self.hazard_classes[affected]
            road_type = attributes[road_type_field_index]
            if road_type.__class__.__name__ == 'QPyNullVariant':
                road_type = tr('Other')
            geom = road.geometry()
            geom.transform(transform)
            length = geom.length()

            if road_type not in self.road_lengths:
                self.road_lengths[road_type] = 0

            if hazard_zone not in self.affected_road_lengths:
                self.affected_road_lengths[hazard_zone] = {}

            if road_type not in self.affected_road_lengths[hazard_zone]:
                self.affected_road_lengths[hazard_zone][road_type] = 0

            self.road_lengths[road_type] += length
            num_classes = len(self.hazard_classes)
            if attributes[target_field_index] in range(num_classes):
                self.affected_road_lengths[hazard_zone][road_type] += length

        impact_summary = self.html_report()

        # For printing map purpose
        map_title = tr('Roads inundated')
        legend_title = tr('Road inundated status')

        style_classes = [
            # FIXME 0 - 0.1
            dict(label=self.hazard_classes[0] + ': 0m',
                 value=0,
                 colour='#00FF00',
                 transparency=0,
                 size=1),
            dict(label=self.hazard_classes[1] + ': <0 - %.1f m' % low_max,
                 value=1,
                 colour='#FFFF00',
                 transparency=0,
                 size=1),
            dict(label=self.hazard_classes[2] + ': %.1f - %.1f m' %
                 (low_max + 0.1, medium_max),
                 value=2,
                 colour='#FFB700',
                 transparency=0,
                 size=1),
            dict(label=self.hazard_classes[3] + ': %.1f - %.1f m' %
                 (medium_max + 0.1, high_max),
                 value=3,
                 colour='#FF6F00',
                 transparency=0,
                 size=1),
            dict(label=self.hazard_classes[4] + ' > %.1f m' % high_max,
                 value=4,
                 colour='#FF0000',
                 transparency=0,
                 size=1),
        ]
        style_info = dict(target_field=target_field,
                          style_classes=style_classes,
                          style_type='categorizedSymbol')

        extra_keywords = {
            'impact_summary': impact_summary,
            'map_title': map_title,
            'legend_title': legend_title,
            'target_field': target_field
        }

        self.set_if_provenance()

        impact_layer_keywords = self.generate_impact_keywords(extra_keywords)

        # Convert QgsVectorLayer to inasafe layer and return it
        line_layer = Vector(data=line_layer,
                            name=tr('Flooded roads'),
                            keywords=impact_layer_keywords,
                            style_info=style_info)
        self._impact = line_layer
        return line_layer
Exemplo n.º 7
0
    def run(self):
        """Run the impact function.

        :returns: A new line layer with inundated roads marked.
        :type: safe_layer
        """
        self.validate()
        self.prepare()

        self.provenance.append_step(
            'Calculating Step',
            'Impact function is calculating the impact.')

        # Thresholds for tsunami hazard zone breakdown.
        low_max = self.parameters['low_threshold'].value
        medium_max = self.parameters['medium_threshold'].value
        high_max = self.parameters['high_threshold'].value

        target_field = self.target_field
        # Get parameters from layer's keywords
        road_class_field = self.exposure.keyword('road_class_field')

        # reproject self.extent to the hazard projection
        hazard_crs = self.hazard.layer.crs()
        hazard_authid = hazard_crs.authid()

        if hazard_authid == 'EPSG:4326':
            viewport_extent = self.requested_extent
        else:
            geo_crs = QgsCoordinateReferenceSystem()
            geo_crs.createFromSrid(4326)
            viewport_extent = extent_to_geo_array(
                QgsRectangle(*self.requested_extent), geo_crs, hazard_crs)

        # Align raster extent and viewport
        # assuming they are both in the same projection
        raster_extent = self.hazard.layer.dataProvider().extent()
        clip_xmin = raster_extent.xMinimum()
        # clip_xmax = raster_extent.xMaximum()
        clip_ymin = raster_extent.yMinimum()
        # clip_ymax = raster_extent.yMaximum()
        if viewport_extent[0] > clip_xmin:
            clip_xmin = viewport_extent[0]
        if viewport_extent[1] > clip_ymin:
            clip_ymin = viewport_extent[1]

        height = ((viewport_extent[3] - viewport_extent[1]) /
                  self.hazard.layer.rasterUnitsPerPixelY())
        height = int(height)
        width = ((viewport_extent[2] - viewport_extent[0]) /
                 self.hazard.layer.rasterUnitsPerPixelX())
        width = int(width)

        raster_extent = self.hazard.layer.dataProvider().extent()
        xmin = raster_extent.xMinimum()
        xmax = raster_extent.xMaximum()
        ymin = raster_extent.yMinimum()
        ymax = raster_extent.yMaximum()

        x_delta = (xmax - xmin) / self.hazard.layer.width()
        x = xmin
        for i in range(self.hazard.layer.width()):
            if abs(x - clip_xmin) < x_delta:
                # We have found the aligned raster boundary
                break
            x += x_delta
            _ = i

        y_delta = (ymax - ymin) / self.hazard.layer.height()
        y = ymin
        for i in range(self.hazard.layer.width()):
            if abs(y - clip_ymin) < y_delta:
                # We have found the aligned raster boundary
                break
            y += y_delta
        clip_extent = [x, y, x + width * x_delta, y + height * y_delta]

        # Clip hazard raster
        small_raster = clip_raster(
            self.hazard.layer, width, height, QgsRectangle(*clip_extent))

        # Create vector features from the flood raster
        # For each raster cell there is one rectangular polygon
        # Data also get spatially indexed for faster operation
        ranges = OrderedDict()
        ranges[0] = [0.0, 0.0]
        ranges[1] = [0.0, low_max]
        ranges[2] = [low_max, medium_max]
        ranges[3] = [medium_max, high_max]
        ranges[4] = [high_max, None]

        index, flood_cells_map = _raster_to_vector_cells(
            small_raster,
            ranges,
            self.exposure.layer.crs())

        # Filter geometry and data using the extent
        ct = QgsCoordinateTransform(
            QgsCoordinateReferenceSystem("EPSG:4326"),
            self.exposure.layer.crs())
        extent = ct.transformBoundingBox(QgsRectangle(*self.requested_extent))
        request = QgsFeatureRequest()
        request.setFilterRect(extent)

        """
        if len(low_max_flood_cells_map) == 0 and \
            len(medium_max_flood_cells_map) == 0 and \
            len(high_max_flood_cells_map) == 0 and \
            len(high_min_flood_cells_map) == 0:
            message = tr(
                'There are no objects in the hazard layer with "value" > 0. '
                'Please check the value or use other extent.' % (
                    threshold_min, ))
            raise GetDataError(message)
        """

        # create template for the output layer
        line_layer_tmp = create_layer(self.exposure.layer)
        new_field = QgsField(target_field, QVariant.Int)
        line_layer_tmp.dataProvider().addAttributes([new_field])
        line_layer_tmp.updateFields()

        # create empty output layer and load it
        filename = unique_filename(suffix='.shp')
        QgsVectorFileWriter.writeAsVectorFormat(
            line_layer_tmp, filename, "utf-8", None, "ESRI Shapefile")
        line_layer = QgsVectorLayer(filename, "flooded roads", "ogr")

        # Do the heavy work - for each road get flood polygon for that area and
        # do the intersection/difference to find out which parts are flooded
        _intersect_lines_with_vector_cells(
            self.exposure.layer,
            request,
            index,
            flood_cells_map,
            line_layer,
            target_field)

        target_field_index = line_layer.dataProvider().\
            fieldNameIndex(target_field)

        # Generate simple impact report
        epsg = get_utm_epsg(self.requested_extent[0], self.requested_extent[1])
        output_crs = QgsCoordinateReferenceSystem(epsg)
        transform = QgsCoordinateTransform(
            self.exposure.layer.crs(), output_crs)

        # Roads breakdown
        self.road_lengths = OrderedDict()
        self.affected_road_categories = self.hazard_classes
        # Impacted roads breakdown
        self.affected_road_lengths = OrderedDict([
            (self.hazard_classes[0], {}),
            (self.hazard_classes[1], {}),
            (self.hazard_classes[2], {}),
            (self.hazard_classes[3], {}),
            (self.hazard_classes[4], {}),
        ])

        if line_layer.featureCount() < 1:
            raise ZeroImpactException()

        roads_data = line_layer.getFeatures()
        road_type_field_index = line_layer.fieldNameIndex(road_class_field)
        for road in roads_data:
            attributes = road.attributes()
            affected = attributes[target_field_index]
            hazard_zone = self.hazard_classes[affected]
            road_type = attributes[road_type_field_index]
            if road_type.__class__.__name__ == 'QPyNullVariant':
                road_type = tr('Other')
            geom = road.geometry()
            geom.transform(transform)
            length = geom.length()

            if road_type not in self.road_lengths:
                self.road_lengths[road_type] = 0

            if hazard_zone not in self.affected_road_lengths:
                self.affected_road_lengths[hazard_zone] = {}

            if road_type not in self.affected_road_lengths[hazard_zone]:
                self.affected_road_lengths[hazard_zone][road_type] = 0

            self.road_lengths[road_type] += length
            num_classes = len(self.hazard_classes)
            if attributes[target_field_index] in range(num_classes):
                self.affected_road_lengths[hazard_zone][road_type] += length

        impact_summary = self.html_report()

        # For printing map purpose
        map_title = tr('Roads inundated')
        legend_title = tr('Road inundated status')

        style_classes = [
            # FIXME 0 - 0.1
            dict(
                label=self.hazard_classes[0] + ': 0m',
                value=0,
                colour='#00FF00',
                transparency=0,
                size=1
            ),
            dict(
                label=self.hazard_classes[1] + ': <0 - %.1f m' % low_max,
                value=1,
                colour='#FFFF00',
                transparency=0,
                size=1
            ),
            dict(
                label=self.hazard_classes[2] + ': %.1f - %.1f m' % (
                    low_max + 0.1, medium_max),
                value=2,
                colour='#FFB700',
                transparency=0,
                size=1
            ),
            dict(
                label=self.hazard_classes[3] + ': %.1f - %.1f m' % (
                    medium_max + 0.1, high_max),
                value=3,
                colour='#FF6F00',
                transparency=0,
                size=1
            ),

            dict(
                label=self.hazard_classes[4] + ' > %.1f m' % high_max,
                value=4,
                colour='#FF0000',
                transparency=0,
                size=1
            ),
        ]
        style_info = dict(
            target_field=target_field,
            style_classes=style_classes,
            style_type='categorizedSymbol')

        extra_keywords = {
            'impact_summary': impact_summary,
            'map_title': map_title,
            'legend_title': legend_title,
            'target_field': target_field
        }

        self.set_if_provenance()

        impact_layer_keywords = self.generate_impact_keywords(extra_keywords)

        # Convert QgsVectorLayer to inasafe layer and return it
        line_layer = Vector(
            data=line_layer,
            name=tr('Flooded roads'),
            keywords=impact_layer_keywords,
            style_info=style_info)
        self._impact = line_layer
        return line_layer
Exemplo n.º 8
0
    def run(self, layers=None):
        """Experimental impact function."""
        self.validate()
        self.prepare(layers)

        target_field = self.target_field
        road_type_field = self.parameters['road_type_field']
        threshold_min = self.parameters['min threshold [m]']
        threshold_max = self.parameters['max threshold [m]']

        if threshold_min > threshold_max:
            message = tr('''The minimal threshold is
                greater then the maximal specified threshold.
                Please check the values.''')
            raise GetDataError(message)

        # Extract data
        H = self.hazard  # Flood
        E = self.exposure  # Roads

        H = H.get_layer()
        E = E.get_layer()

        # Get necessary width and height of raster
        height = (self.requested_extent[3] -
                  self.requested_extent[1]) / (H.rasterUnitsPerPixelY())
        height = int(height)
        width = (self.requested_extent[2] -
                 self.requested_extent[0]) / (H.rasterUnitsPerPixelX())
        width = int(width)

        # Align raster extent and self.extent
        raster_extent = H.dataProvider().extent()
        xmin = raster_extent.xMinimum()
        xmax = raster_extent.xMaximum()
        ymin = raster_extent.yMinimum()
        ymax = raster_extent.yMaximum()

        x_delta = (xmax - xmin) / H.width()
        x = xmin
        for i in range(H.width()):
            if abs(x - self.requested_extent[0]) < x_delta:
                # We have found the aligned raster boundary
                break
            x += x_delta
            _ = i

        y_delta = (ymax - ymin) / H.height()
        y = ymin
        for i in range(H.width()):
            if abs(y - self.requested_extent[1]) < y_delta:
                # We have found the aligned raster boundary
                break
            y += y_delta
        clip_extent = [x, y, x + width * x_delta, y + height * y_delta]

        # Clip and polygonize
        small_raster = clip_raster(H, width, height,
                                   QgsRectangle(*clip_extent))
        flooded_polygon = polygonize(small_raster, threshold_min,
                                     threshold_max)

        # Filter geometry and data using the extent
        requested_extent = QgsRectangle(*self.requested_extent)
        request = QgsFeatureRequest()
        request.setFilterRect(requested_extent)

        if flooded_polygon is None:
            message = tr('''There are no objects
                in the hazard layer with
                "value">'%s'.
                Please check the value or use other
                extent.''' % (threshold_min, ))
            raise GetDataError(message)

        # Clip exposure by the extent
        extent_as_polygon = QgsGeometry().fromRect(requested_extent)
        line_layer = clip_by_polygon(E, extent_as_polygon)
        # Find inundated roads, mark them
        line_layer = split_by_polygon(line_layer,
                                      flooded_polygon,
                                      request,
                                      mark_value=(target_field, 1))

        # Find inundated roads, mark them
        # line_layer = split_by_polygon(
        #     E,
        #     flooded_polygon,
        #     request,
        #     mark_value=(target_field, 1))
        target_field_index = line_layer.dataProvider().\
            fieldNameIndex(target_field)

        # Generate simple impact report
        epsg = get_utm_epsg(self.requested_extent[0], self.requested_extent[1])
        output_crs = QgsCoordinateReferenceSystem(epsg)
        transform = QgsCoordinateTransform(E.crs(), output_crs)
        road_len = flooded_len = 0  # Length of roads
        roads_by_type = dict()  # Length of flooded roads by types

        roads_data = line_layer.getFeatures()
        road_type_field_index = line_layer.fieldNameIndex(road_type_field)
        for road in roads_data:
            attributes = road.attributes()
            road_type = attributes[road_type_field_index]
            if road_type.__class__.__name__ == 'QPyNullVariant':
                road_type = tr('Other')
            geom = road.geometry()
            geom.transform(transform)
            length = geom.length()
            road_len += length

            if road_type not in roads_by_type:
                roads_by_type[road_type] = {'flooded': 0, 'total': 0}
            roads_by_type[road_type]['total'] += length

            if attributes[target_field_index] == 1:
                flooded_len += length
                roads_by_type[road_type]['flooded'] += length

        table_body = self._tabulate(flooded_len, self.question, road_len,
                                    roads_by_type)

        impact_summary = Table(table_body).toNewlineFreeString()
        map_title = tr('Roads inundated')

        style_classes = [
            dict(label=tr('Not Inundated'),
                 value=0,
                 colour='#1EFC7C',
                 transparency=0,
                 size=0.5),
            dict(label=tr('Inundated'),
                 value=1,
                 colour='#F31A1C',
                 transparency=0,
                 size=0.5)
        ]
        style_info = dict(target_field=target_field,
                          style_classes=style_classes,
                          style_type='categorizedSymbol')

        # Convert QgsVectorLayer to inasafe layer and return it
        line_layer = Vector(data=line_layer,
                            name=tr('Flooded roads'),
                            keywords={
                                'impact_summary': impact_summary,
                                'map_title': map_title,
                                'target_field': target_field
                            },
                            style_info=style_info)
        self._impact = line_layer
        return line_layer
Exemplo n.º 9
0
    def run(self, layers=None):
        """Experimental impact function."""
        self.validate()
        self.prepare(layers)

        target_field = self.target_field
        road_type_field = self.parameters['road_type_field']
        threshold_min = self.parameters['min threshold [m]']
        threshold_max = self.parameters['max threshold [m]']

        if threshold_min > threshold_max:
            message = tr('''The minimal threshold is
                greater then the maximal specified threshold.
                Please check the values.''')
            raise GetDataError(message)

        # Extract data
        H = self.hazard    # Flood
        E = self.exposure  # Roads

        H = H.get_layer()
        E = E.get_layer()

        # Get necessary width and height of raster
        height = (self.requested_extent[3] - self.requested_extent[1]) / (
            H.rasterUnitsPerPixelY())
        height = int(height)
        width = (self.requested_extent[2] - self.requested_extent[0]) / (
            H.rasterUnitsPerPixelX())
        width = int(width)

        # Align raster extent and self.extent
        raster_extent = H.dataProvider().extent()
        xmin = raster_extent.xMinimum()
        xmax = raster_extent.xMaximum()
        ymin = raster_extent.yMinimum()
        ymax = raster_extent.yMaximum()

        x_delta = (xmax - xmin) / H.width()
        x = xmin
        for i in range(H.width()):
            if abs(x - self.requested_extent[0]) < x_delta:
                # We have found the aligned raster boundary
                break
            x += x_delta
            _ = i

        y_delta = (ymax - ymin) / H.height()
        y = ymin
        for i in range(H.width()):
            if abs(y - self.requested_extent[1]) < y_delta:
                # We have found the aligned raster boundary
                break
            y += y_delta
        clip_extent = [x, y, x + width * x_delta, y + height * y_delta]

        # Clip and polygonize
        small_raster = clip_raster(
            H, width, height, QgsRectangle(*clip_extent))
        flooded_polygon = polygonize(
            small_raster, threshold_min, threshold_max)

        # Filter geometry and data using the extent
        requested_extent = QgsRectangle(*self.requested_extent)
        request = QgsFeatureRequest()
        request.setFilterRect(requested_extent)

        if flooded_polygon is None:
            message = tr('''There are no objects
                in the hazard layer with
                "value">'%s'.
                Please check the value or use other
                extent.''' % (threshold_min, ))
            raise GetDataError(message)

        # Clip exposure by the extent
        extent_as_polygon = QgsGeometry().fromRect(requested_extent)
        line_layer = clip_by_polygon(
            E,
            extent_as_polygon
        )
        # Find inundated roads, mark them
        line_layer = split_by_polygon(
            line_layer,
            flooded_polygon,
            request,
            mark_value=(target_field, 1))

        # Find inundated roads, mark them
        # line_layer = split_by_polygon(
        #     E,
        #     flooded_polygon,
        #     request,
        #     mark_value=(target_field, 1))
        target_field_index = line_layer.dataProvider().\
            fieldNameIndex(target_field)

        # Generate simple impact report
        epsg = get_utm_epsg(self.requested_extent[0], self.requested_extent[1])
        output_crs = QgsCoordinateReferenceSystem(epsg)
        transform = QgsCoordinateTransform(E.crs(), output_crs)
        road_len = flooded_len = 0  # Length of roads
        roads_by_type = dict()      # Length of flooded roads by types

        roads_data = line_layer.getFeatures()
        road_type_field_index = line_layer.fieldNameIndex(road_type_field)
        for road in roads_data:
            attributes = road.attributes()
            road_type = attributes[road_type_field_index]
            if road_type.__class__.__name__ == 'QPyNullVariant':
                road_type = tr('Other')
            geom = road.geometry()
            geom.transform(transform)
            length = geom.length()
            road_len += length

            if road_type not in roads_by_type:
                roads_by_type[road_type] = {'flooded': 0, 'total': 0}
            roads_by_type[road_type]['total'] += length

            if attributes[target_field_index] == 1:
                flooded_len += length
                roads_by_type[road_type]['flooded'] += length

        table_body = self._tabulate(flooded_len, self.question, road_len,
                                    roads_by_type)

        impact_summary = Table(table_body).toNewlineFreeString()
        map_title = tr('Roads inundated')

        style_classes = [dict(label=tr('Not Inundated'), value=0,
                              colour='#1EFC7C', transparency=0, size=0.5),
                         dict(label=tr('Inundated'), value=1,
                              colour='#F31A1C', transparency=0, size=0.5)]
        style_info = dict(target_field=target_field,
                          style_classes=style_classes,
                          style_type='categorizedSymbol')

        # Convert QgsVectorLayer to inasafe layer and return it
        line_layer = Vector(
            data=line_layer,
            name=tr('Flooded roads'),
            keywords={'impact_summary': impact_summary,
                      'map_title': map_title,
                      'target_field': target_field},
            style_info=style_info)
        self._impact = line_layer
        return line_layer
Exemplo n.º 10
0
    def run(self):
        """Run the impact function.

        :returns: A new line layer with inundated roads marked.
        :type: safe_layer
        """
        self.validate()
        self.prepare()

        target_field = self.target_field
        # Get parameters from layer's keywords
        road_class_field = self.exposure.keyword('road_class_field')
        # Get parameters from IF parameter
        threshold_min = self.parameters['min threshold'].value
        threshold_max = self.parameters['max threshold'].value

        if threshold_min > threshold_max:
            message = tr(
                'The minimal threshold is greater than the maximal specified '
                'threshold. Please check the values.')
            raise GetDataError(message)

        # reproject self.extent to the hazard projection
        hazard_crs = self.hazard.layer.crs()
        hazard_authid = hazard_crs.authid()

        if hazard_authid == 'EPSG:4326':
            viewport_extent = self.requested_extent
        else:
            geo_crs = QgsCoordinateReferenceSystem()
            geo_crs.createFromSrid(4326)
            viewport_extent = extent_to_geo_array(
                QgsRectangle(*self.requested_extent), geo_crs, hazard_crs)

        # Align raster extent and viewport
        # assuming they are both in the same projection
        raster_extent = self.hazard.layer.dataProvider().extent()
        clip_xmin = raster_extent.xMinimum()
        # clip_xmax = raster_extent.xMaximum()
        clip_ymin = raster_extent.yMinimum()
        # clip_ymax = raster_extent.yMaximum()
        if viewport_extent[0] > clip_xmin:
            clip_xmin = viewport_extent[0]
        if viewport_extent[1] > clip_ymin:
            clip_ymin = viewport_extent[1]
        # TODO: Why have these two clauses when they are not used?
        # Commenting out for now.
        # if viewport_extent[2] < clip_xmax:
        #     clip_xmax = viewport_extent[2]
        # if viewport_extent[3] < clip_ymax:
        #     clip_ymax = viewport_extent[3]

        height = ((viewport_extent[3] - viewport_extent[1]) /
                  self.hazard.layer.rasterUnitsPerPixelY())
        height = int(height)
        width = ((viewport_extent[2] - viewport_extent[0]) /
                 self.hazard.layer.rasterUnitsPerPixelX())
        width = int(width)

        raster_extent = self.hazard.layer.dataProvider().extent()
        xmin = raster_extent.xMinimum()
        xmax = raster_extent.xMaximum()
        ymin = raster_extent.yMinimum()
        ymax = raster_extent.yMaximum()

        x_delta = (xmax - xmin) / self.hazard.layer.width()
        x = xmin
        for i in range(self.hazard.layer.width()):
            if abs(x - clip_xmin) < x_delta:
                # We have found the aligned raster boundary
                break
            x += x_delta
            _ = i

        y_delta = (ymax - ymin) / self.hazard.layer.height()
        y = ymin
        for i in range(self.hazard.layer.width()):
            if abs(y - clip_ymin) < y_delta:
                # We have found the aligned raster boundary
                break
            y += y_delta
        clip_extent = [x, y, x + width * x_delta, y + height * y_delta]

        # Clip hazard raster
        small_raster = clip_raster(
            self.hazard.layer, width, height, QgsRectangle(*clip_extent))

        # Create vector features from the flood raster
        # For each raster cell there is one rectangular polygon
        # Data also get spatially indexed for faster operation
        index, flood_cells_map = _raster_to_vector_cells(
            small_raster,
            threshold_min,
            threshold_max,
            self.exposure.layer.crs())

        # Filter geometry and data using the extent
        ct = QgsCoordinateTransform(
            QgsCoordinateReferenceSystem("EPSG:4326"),
            self.exposure.layer.crs())
        extent = ct.transformBoundingBox(QgsRectangle(*self.requested_extent))
        request = QgsFeatureRequest()
        request.setFilterRect(extent)

        if len(flood_cells_map) == 0:
            message = tr(
                'There are no objects in the hazard layer with "value" > %s. '
                'Please check the value or use other extent.' % (
                    threshold_min, ))
            raise GetDataError(message)

        # create template for the output layer
        line_layer_tmp = create_layer(self.exposure.layer)
        new_field = QgsField(target_field, QVariant.Int)
        line_layer_tmp.dataProvider().addAttributes([new_field])
        line_layer_tmp.updateFields()

        # create empty output layer and load it
        filename = unique_filename(suffix='.shp')
        QgsVectorFileWriter.writeAsVectorFormat(
            line_layer_tmp, filename, "utf-8", None, "ESRI Shapefile")
        line_layer = QgsVectorLayer(filename, "flooded roads", "ogr")

        # Do the heavy work - for each road get flood polygon for that area and
        # do the intersection/difference to find out which parts are flooded
        _intersect_lines_with_vector_cells(
            self.exposure.layer,
            request,
            index,
            flood_cells_map,
            line_layer,
            target_field)

        target_field_index = line_layer.dataProvider().\
            fieldNameIndex(target_field)

        # Generate simple impact report
        epsg = get_utm_epsg(self.requested_extent[0], self.requested_extent[1])
        output_crs = QgsCoordinateReferenceSystem(epsg)
        transform = QgsCoordinateTransform(
            self.exposure.layer.crs(), output_crs)
        flooded_keyword = tr('Flooded in the threshold (m)')
        self.affected_road_categories = [flooded_keyword]
        self.affected_road_lengths = OrderedDict([
            (flooded_keyword, {})])
        self.road_lengths = OrderedDict()

        if line_layer.featureCount() < 1:
            raise ZeroImpactException()

        roads_data = line_layer.getFeatures()
        road_type_field_index = line_layer.fieldNameIndex(road_class_field)
        for road in roads_data:
            attributes = road.attributes()
            road_type = attributes[road_type_field_index]
            if road_type.__class__.__name__ == 'QPyNullVariant':
                road_type = tr('Other')
            geom = road.geometry()
            geom.transform(transform)
            length = geom.length()

            if road_type not in self.road_lengths:
                self.affected_road_lengths[flooded_keyword][road_type] = 0
                self.road_lengths[road_type] = 0

            self.road_lengths[road_type] += length
            if attributes[target_field_index] == 1:
                self.affected_road_lengths[
                    flooded_keyword][road_type] += length

        impact_summary = self.html_report()

        # For printing map purpose
        map_title = tr('Roads inundated')
        legend_title = tr('Road inundated status')

        style_classes = [
            dict(
                label=tr('Not Inundated'), value=0,
                colour='#1EFC7C', transparency=0, size=0.5),
            dict(
                label=tr('Inundated'), value=1,
                colour='#F31A1C', transparency=0, size=0.5)]
        style_info = dict(
            target_field=target_field,
            style_classes=style_classes,
            style_type='categorizedSymbol')

        # Convert QgsVectorLayer to inasafe layer and return it
        line_layer = Vector(
            data=line_layer,
            name=tr('Flooded roads'),
            keywords={
                'impact_summary': impact_summary,
                'map_title': map_title,
                'legend_title': legend_title,
                'target_field': target_field},
            style_info=style_info)
        self._impact = line_layer
        return line_layer