Source code for safe.impact_functions.inundation.flood_vector_building_impact.impact_function

# coding=utf-8
"""InaSAFE Disaster risk tool by Australian Aid - Flood Vector Impact on
Buildings using QGIS.

Contact : [email protected]

.. note:: This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 2 of the License, or
     (at your option) any later version.

"""

from collections import OrderedDict
from qgis.core import (
    QgsField,
    QgsSpatialIndex,
    QgsVectorLayer,
    QgsFeature,
    QgsRectangle,
    QgsFeatureRequest,
    QgsCoordinateTransform,
    QgsCoordinateReferenceSystem,
    QgsGeometry)

from PyQt4.QtCore import QVariant

from safe.impact_functions.bases.classified_vh_classified_ve import \
    ClassifiedVHClassifiedVE
from safe.impact_functions.inundation.flood_vector_building_impact.\
    metadata_definitions import FloodPolygonBuildingFunctionMetadata
from safe.utilities.i18n import tr
from safe.utilities.gis import is_point_layer
from safe.storage.vector import Vector
from safe.common.exceptions import GetDataError, ZeroImpactException
from safe.impact_reports.building_exposure_report_mixin import (
    BuildingExposureReportMixin)
import safe.messaging as m
from safe.messaging import styles


[docs]class FloodPolygonBuildingFunction( ClassifiedVHClassifiedVE, BuildingExposureReportMixin): # noinspection PyUnresolvedReferences """Impact function for inundation (polygon-polygon).""" _metadata = FloodPolygonBuildingFunctionMetadata() def __init__(self): super(FloodPolygonBuildingFunction, self).__init__() # The 'wet' variable self.wet = 'wet'
[docs] def notes(self): """Return the notes section of the report. :return: The notes that should be attached to this impact report. :rtype: safe.messaging.Message """ message = m.Message(style_class='container') message.add(m.Heading( tr('Notes and assumptions'), **styles.INFO_STYLE)) checklist = m.BulletedList() checklist.add(tr( 'Buildings are flooded when in a region with ' 'field "%s" in "%s".') % ( self.hazard_class_attribute, ', '.join([ unicode(hazard_class) for hazard_class in self.hazard_class_mapping[self.wet] ]))) message.add(checklist) return message
[docs] def run(self): """Experimental impact function.""" self.validate() self.prepare() # Get parameters from layer's keywords self.hazard_class_attribute = self.hazard.keyword('field') self.hazard_class_mapping = self.hazard.keyword('value_map') self.exposure_class_attribute = self.exposure.keyword( 'structure_class_field') # Prepare Hazard Layer hazard_provider = self.hazard.layer.dataProvider() # Check affected field exists in the hazard layer affected_field_index = hazard_provider.fieldNameIndex( self.hazard_class_attribute) if affected_field_index == -1: message = tr( 'Field "%s" is not present in the attribute table of the ' 'hazard layer. Please change the Affected Field parameter in ' 'the IF Option.') % self.hazard_class_attribute raise GetDataError(message) srs = self.exposure.layer.crs().toWkt() exposure_provider = self.exposure.layer.dataProvider() exposure_fields = exposure_provider.fields() # Check self.exposure_class_attribute exists in exposure layer building_type_field_index = exposure_provider.fieldNameIndex( self.exposure_class_attribute) if building_type_field_index == -1: message = tr( 'Field "%s" is not present in the attribute table of ' 'the exposure layer. Please change the Building Type ' 'Field parameter in the IF Option.' ) % self.exposure_class_attribute raise GetDataError(message) # If target_field does not exist, add it: if exposure_fields.indexFromName(self.target_field) == -1: exposure_provider.addAttributes( [QgsField(self.target_field, QVariant.Int)]) target_field_index = exposure_provider.fieldNameIndex( self.target_field) exposure_fields = exposure_provider.fields() # Create layer to store the buildings from E and extent if is_point_layer(self.exposure.layer): building_layer = QgsVectorLayer( 'Point?crs=' + srs, 'impact_buildings', 'memory') else: building_layer = QgsVectorLayer( 'Polygon?crs=' + srs, 'impact_buildings', 'memory') building_provider = building_layer.dataProvider() # Set attributes building_provider.addAttributes(exposure_fields.toList()) building_layer.startEditing() building_layer.commitChanges() # Filter geometry and data using the requested extent requested_extent = QgsRectangle(*self.requested_extent) # This is a hack - we should be setting the extent CRS # in the IF base class via safe/engine/core.py:calculate_impact # for now we assume the extent is in 4326 because it # is set to that from geo_extent # See issue #1857 transform = QgsCoordinateTransform( QgsCoordinateReferenceSystem( 'EPSG:%i' % self._requested_extent_crs), self.hazard.layer.crs() ) projected_extent = transform.transformBoundingBox(requested_extent) request = QgsFeatureRequest() request.setFilterRect(projected_extent) # Split building_layer by H and save as result: # 1) Filter from H inundated features # 2) Mark buildings as inundated (1) or not inundated (0) # make spatial index of affected polygons hazard_index = QgsSpatialIndex() hazard_geometries = {} # key = feature id, value = geometry has_hazard_objects = False for feature in self.hazard.layer.getFeatures(request): value = feature[affected_field_index] if value not in self.hazard_class_mapping[self.wet]: continue hazard_index.insertFeature(feature) hazard_geometries[feature.id()] = QgsGeometry(feature.geometry()) has_hazard_objects = True if not has_hazard_objects: message = tr( 'There are no objects in the hazard layer with %s ' 'value in %s. Please check your data or use another ' 'attribute.') % ( self.hazard_class_attribute, ', '.join(self.hazard_class_mapping[self.wet])) raise GetDataError(message) features = [] for feature in self.exposure.layer.getFeatures(request): building_geom = feature.geometry() affected = False # get tentative list of intersecting hazard features # only based on intersection of bounding boxes ids = hazard_index.intersects(building_geom.boundingBox()) for fid in ids: # run (slow) exact intersection test if hazard_geometries[fid].intersects(building_geom): affected = True break f = QgsFeature() f.setGeometry(building_geom) f.setAttributes(feature.attributes()) f[target_field_index] = 1 if affected else 0 features.append(f) # every once in a while commit the created features # to the output layer if len(features) == 1000: (_, __) = building_provider.addFeatures(features) features = [] (_, __) = building_provider.addFeatures(features) building_layer.updateExtents() # Generate simple impact report self.buildings = {} self.affected_buildings = OrderedDict([ (tr('Flooded'), {}) ]) buildings_data = building_layer.getFeatures() building_type_field_index = building_layer.fieldNameIndex( self.exposure_class_attribute) for building in buildings_data: record = building.attributes() building_type = record[building_type_field_index] if building_type in [None, 'NULL', 'null', 'Null']: building_type = 'Unknown type' if building_type not in self.buildings: self.buildings[building_type] = 0 for category in self.affected_buildings.keys(): self.affected_buildings[category][ building_type] = OrderedDict([ (tr('Buildings Affected'), 0)]) self.buildings[building_type] += 1 if record[target_field_index] == 1: self.affected_buildings[tr('Flooded')][building_type][ tr('Buildings Affected')] += 1 # Lump small entries and 'unknown' into 'other' category self._consolidate_to_other() impact_summary = self.html_report() # For printing map purpose map_title = tr('Buildings inundated') legend_title = tr('Structure 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=self.target_field, style_classes=style_classes, style_type='categorizedSymbol') # Convert QgsVectorLayer to inasafe layer and return it. if building_layer.featureCount() < 1: raise ZeroImpactException(tr( 'No buildings were impacted by this flood.')) building_layer = Vector( data=building_layer, name=tr('Flooded buildings'), keywords={ 'impact_summary': impact_summary, 'map_title': map_title, 'legend_title': legend_title, 'target_field': self.target_field, 'buildings_total': self.total_buildings, 'buildings_affected': self.total_affected_buildings}, style_info=style_info) self._impact = building_layer return building_layer