Vector-based Approach

This page explains how to use DamageScanner with vector-based exposure data (e.g. shapefiles, GeoPackages, or OSM data). This approach is ideal for object-level damage estimation, such as buildings, roads, power plants, and other individual infrastructure assets.

When to Use Vector-Based Workflows

Scenario	Raster-Based	Vector-Based
Infrastructure objects (e.g. bridges, roads)	❌	✅
OpenStreetMap data	❌	✅
Detailed local studies	❌	✅
Exposure linked to specific geometries	❌	✅

Required Inputs

As described in the Overview, you need:

Hazard raster (e.g. flood depth, wind speed)
Exposure vector (e.g. buildings, roads — as .shp, .gpkg, .pbf, or GeoDataFrame)
Vulnerability curves (CSV or DataFrame)
Maximum damage values (CSV, dict, or DataFrame)

⚠️ Your exposure data must include a column specifying asset type, matching the keys used in the vulnerability curves and max damage data.

Minimal Working Example

from damagescanner import DamageScanner

hazard = "data/hazard_flood_depth.tif"
feature_data = "data/infrastructure_osm.gpkg"
curves = "data/vulnerability_curves.csv"
maxdam = "data/maxdam.csv"

scanner = DamageScanner(hazard, feature_data, curves, maxdam)
damage = scanner.calculate()

The result is a GeoDataFrame of features with estimated direct damage values per asset.

Key Behavior

The exposure file must contain geometry columns (Point, LineString, or Polygon)
DamageScanner overlays each geometry with the hazard raster
It then samples the hazard value and looks up the damage fraction from the corresponding vulnerability curve
The damage is calculated as:

\ exposure_area * damage_fraction * max_damage

⚠️ Geometry Handling Tips

⚠️ Mixed Geometry Types — Avoid mixing Points and Polygons for the same asset type.

⚠️ CRS Alignment — Both hazard and vector data must be in the same coordinate reference system.

⚠️ Object Column — You must define a column that links each object to a vulnerability curve and max damage.

📚 See Also

API Documentation

`vector`

Vector-based damage estimation functions for DamageScanner.

`VectorExposure(hazard_file, feature_file, asset_type='roads', object_col='object_type', hazard_value_col='band_data', disable_progress=False, gridded=True, extract_strategy='raster-sequential', return_full=True)`

Load and overlay vector or raster hazard with vector exposure data.

Parameters:

Name	Type	Description	Default
`hazard_file`	`Path \| Dataset \| DataArray \| DatasetReader \| GeoDataFrame`	Hazard input.	required
`feature_file`	`Path \| GeoDataFrame \| DataFrame \| str`	Exposure input.	required
`asset_type`	`str \| None`	Infrastructure category (only for OSM).	`'roads'`
`object_col`	`str`	Name of the object type column.	`'object_type'`
`hazard_value_col`	`str`	Column name in vector hazard containing intensity values.	`'band_data'`
`disable_progress`	`bool`	Whether to suppress progress bars.	`False`
`gridded`	`bool`	Whether to process in spatial chunks.	`True`
`extract_strategy`	`str`	exactextract strategy - "feature-sequential" or "raster-sequential".	`'raster-sequential'`
`return_full`	`bool`	Whether to return all features, even those with no hazard intersection.	`True`

Returns:

Name	Type	Description
`tuple`	`tuple[GeoDataFrame, str, CRS \| None, float \| None]`	(features, object_col, hazard_crs, cell_area_m2)

Raises:

Type	Description
`ValueError`	If input files are not in expected formats or if geometry types are unsupported.

`VectorScanner(hazard_file, feature_file, curve_path, maxdam_path=None, asset_type=None, multi_curves=dict(), object_col='object_type', hazard_value_col='band_data', disable_progress=False, gridded=True, extract_strategy='raster-sequential', return_full=True)`

Perform vector-based direct damage assessment using hazard and exposure layers.

Parameters:

Name	Type	Description	Default
`hazard_file`	`Path \| Dataset \| DataArray \| GeoDataFrame \| str`	Hazard input.	required
`feature_file`	`Path \| GeoDataFrame \| str`	Exposure input.	required
`curve_path`	`Path \| DataFrame \| str`	Vulnerability curve(s).	required
`maxdam_path`	`Path \| DataFrame \| dict \| None`	Maximum damage values.	`None`
`asset_type`	`str \| None`	Infrastructure class (only for OSM).	`None`
`multi_curves`	`dict`	Multiple curve sets.	`dict()`
`object_col`	`str`	Column name with object type.	`'object_type'`
`hazard_value_col`	`str`	Column name in vector hazard containing intensity values.	`'band_data'`
`disable_progress`	`bool`	Whether to suppress progress bars.	`False`
`gridded`	`bool`	Whether to process in spatial chunks.	`True`
`extract_strategy`	`str`	exactextract strategy - "feature-sequential" or "raster-sequential".	`'raster-sequential'`
`return_full`	`bool`	Whether to return all features, even those with no hazard intersection.	`True`

Returns:

Type	Description
`GeoDataFrame`	Exposure data with calculated damages.

Raises:

Type	Description
`ValueError`	If input files are of unsupported formats or if geometry types are not supported.
`KeyError`	If object types in exposure are not covered by maximum damage data.