Exposure data
In the table down below, an overview is provided od the necessary inputs in either the geometry file or the csv file“.
| Field | Required | Multiple | Example |
|---|---|---|---|
| object_id | Yes | - | 1 |
| object_name | No | - | fp_1 |
| extract_method | Yes | - | centroid |
| fn_< any >_< any > | Yes | Yes | struct_2 |
| ground_flht | No | - | 4 |
| ground_elevtn | No | - | 10.11 |
| max_< any >_< any > | Yes | Yes | 193457.00 |
| < Additional attributes > | No | 1205 |
A more detailed description of the data fields can be found below.
Object ID
The object ID is used to link the geometries to the information in the exposure CSV. The object ID must be unique for each object. At the moment of writing, FIAT does not check whether the object IDs are indeed unique and it is the responsibility of the user to ensure this. At a later stage, FIAT will have a built-in check for this.
Object name
The object name field can be chosen freely and can serve as a field for identifying the damages assets.
Extraction Method
The extraction method refers to how the water level or water depth is sampled per asset. The options are (1) centroid, which samples the water level or depth at the estimated centroid inside of the asset, or (2) area, which considers the water level or depth over the entire polygon or line and takes either an average or maximum. The user can set the choice for the latter per damage function, in the vulnerability curves file.
In case the user selects ‘area’ as extraction method for certain assets, the geometries related to those assets should be a line or polygon.
Damage Functions
The user can input as many damage functions and related max potential damages as required. However, at least one damage function and related max potential damage must be provides per asset. Damage function column are named as fn_< exposure_type >_< component > (for exposure types, see here). This name can be chosen freely but it is recommended to give it a descriptive name, such as damage (exposure type) in combination with structure or content (components), and it is required to use the same name in the max potential damage column. (i.e. max_< exposure-type >_< component >) The value that must be entered is the name of the damage function, relating to the names in the corresponding damage functions in the vulnerability curves file. Globally, continental damage functions can be obtained from European Commission’s Joint Research Centre, but it is recommended to use more location-specific functions when available.
Ground Floor Height
The ground floor height column indicates the height of the ground floor of an asset above the ground elevation. For example, when a building is built on poles, the ground floor (finished floor in the US) is lifted off the ground with a certain height. Usually, buildings are at least a certain amount above ground elevation because of the road and sidewalk. This value is used to calculate the water depth inside of the asset, for buildings.
Required for flood damage calculation, see global model types
Ground Elevation
The ground elevation is the value of a digital elevation model (DEM) at the location of the asset.
Required for flood damage calculation, see global model types
Max Potential Damage
The maximum potential damage corresponds to the damage functions for each asset. For each damage function type that was assigned, a maximum potential damage must also be assigned. These values represent the maximum damage to, for example, the structure, content, or other (e.g. inventory). There are methods to derive these values, based on building type and area of the building. Globally, maximum damage values per country can be obtained from European Commission’s Joint Research Centre, but it is recommended to use more location-specific damage values. In the US, FEMA Hazus is an industry standard in how to derive these values.
Additional attributes
Attitional attributes can be added to the exposure CSV file. The added columns can be named freely. The resulting FIAT output contains all data that was put in, therefore they can be used by the FIAT Toolbox to calculate user-specified output metrics. For example, a user could configure the output metrics to always show the number of people affected with a high social vulnerability, per administrative region. The user can add columns to the CSV file manually or with the help of the HydroMT-FIAT model builder, in which the user is free to select a descriptive ‘Label name’ for the additional attributes. If the user wishes to connect the damages per administrative or other aggregation area to a GIS file, the **FIAT Toolbox offers a post-processing tool to do so.