6. Hazard extraction

Polygonize a single hazard file

gmtra.hazard.single_polygonized(flood_scen, region, geometry, country_ISO3, hzd='FU')

Function to overlay a surface or river flood hazard map with the infrastructure assets.

Arguments:

flood_scen : Unique ID for the flood scenario to be used.

region : Unique ID of the region that is intersected.

geometry : Shapely geometry of the region that is being intersected.

country_ISO3 : ISO3 code of the country in which the region is situated. Required to get the FATHOM flood maps.

Optional Arguments:

hzd : Default is FU. Can be changed to PU for surface flooding.

Returns:

gdf : A GeoDataFrame where each row is a poylgon with the same flood depth.

Polygonize multiple hazard files

gmtra.hazard.multiple_polygonized(region, geometry, hzd_list, hzd_names)

Function to overlay a set of hazard maps with infrastructure assets. This function is used for Earthquakes, Coastal floods and Cyclones (the hazard maps with global coverage).

Arguments:

region : Unique ID of the region that is intersected.

geometry : Shapely geometry of the region that is being intersected.

hzd_list : list of file paths to each hazard. Make sure hzd_list and hzd_names are matching.

hzd_names : llist of unique hazard IDs. Most often these are the return periods.

Returns:

gdf : A GeoDataFrame where each row is a poylgon with the same hazard value.

Intersect an infrastructure asset with hazard maps

gmtra.hazard.intersect_hazard(x, hzd_reg_sindex, hzd_region, liquefaction=False)

Function to intersect an infrastructure asset (within a GeoDataFrame) with the hazard maps.

Arguments:

x : row in a GeoDataFrame that represents an unique infrastructure asset.

hzd_reg_sindex : Spatial Index of the hazard GeoDataFrame.

hzd_region : GeoDataFrame of a unique hazard map.

Optional arguments:

liquefaction : Default is False. Set to True if you are intersecting with the liquefaction map.

Returns:

tuple : a shapely.geometry of the part of the asset that is affected and the average hazard value in this intersection.

Intersect all assets in a region with a hazard

gmtra.hazard.region_intersection(n, hzd, rail=False)

Function to intersect all return periods of a particualar hazard with all road or railway assets in the specific region.

Arguments:

n : the index ID of a region in the specified shapefile with all the regions.

hzd : abbrevation of the hazard we want to intersect. EQ for earthquakes, Cyc for cyclones, FU for river flooding, PU for surface flooding and CF for coastal flooding.

Optional Arguments:

rail : Default is False. Set to True if you would like to intersect the railway assets in a region.

Returns:

output : a GeoDataFrame with all intersections between the infrastructure assets and the specified hazard. Will also be saved as .feather file.

Intersect all assets in a region with a global liquefaction map

gmtra.hazard.get_liquefaction_region(n, rail=False)

Function to intersect all return periods of a particualar hazard with all road or railway assets in the specific region.

Arguments:

n : the index ID of a region in the specified shapefile with all the regions.

Optional Arguments:

rail : Default is False. Set to True if you would like to intersect the railway assets in a region.

Returns:

output : a GeoDataFrame with all intersections between the infrastructure assets and the liquefaction map. Will be saved as .feather file.

Intersect all assets in a region with a global tree density map

gmtra.hazard.get_tree_density(n, rail=False)

Function to intersect all return periods of a particualar hazard with all road or railway assets in the specific region.

Arguments:

n : the index ID of a region in the specified shapefile with all the regions.

Optional Arguments:

rail : Default is False. Set to True if you would like to intersect the railway assets in a region.

Returns:

output : a GeoDataFrame with all intersections between the infrastructure assets and the liquefaction map. Will be saved as .feather file.