ISL 2004

Spatial Multi Criteria Evaluation for Vulnerability

Assessment

Cees van WestenUnited Nations University – ITC School for Disaster Geo-Information

ManagementInternational Institute for Geo-Information Science and Earth

Observation (ITC)Enschede, The Netherlands

E-mail: westen@itc.nl Associated Institute of the

This week

Today: Presentations of hazard assessment exercises

Afternoon: SMCE Wednesday: participatory GIS Thursday: physical vulnerability

assessment Friday: quantitative risk assessment

Presentations

Erosion from Pyroclastic flow deposits: case study Pinatubo (Raphael Spiekermann)

Flood hazard assessment using 2D flood propagation model outputs (Sandra Traper)

Bangladesh SPOT multi temporal flood mapping (Stefan Premm)

Modelling of Land Subsidence & Sea level rise in Semarang city, Indonesia (Tobias Grau)

Landslide susceptibility assessment using statistical method (Ekrem Canli)

Deterministic landslide hazard assessment (Bernd Loigge) Seismic hazard assessment

Framework

Input data Susceptibility

Initiation Runout

Hazard assessment Vulnerability Risk assessment

Quantitative Qualitative

Spatial Multi Criteria Evaluation

ISL 2004

SMCE

Spatial Multi Criteria Evaluation.

You can combine all types of data

Define goal & subgoals

Select indicators Make a decision

tree Standardize Weighting Combination Classification

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SMCE process

Identification of the main goal. Identification of a hierarchy of sub goals. Identification of criteria or effects, which measure the

performance of the sub goals. Creating and filling a criteria tree, which represents the

hierarchy of the main goal, any sub goals, and the criteria.

Identification of alternatives to be evaluated. Assignment of input maps to criteria for each

alternative. Determination of a standardization method per criterion. Weighing of criteria in the criteria tree. Calculation of the Composite Index maps and

visualization. Classifying or slicing the Composite Index maps and

visualization. Calculation of Shape Index and/or Connectivity Index.

Spatial Multi Criteria Evaluation

Composite multi- hazard risk index for Cuba at national scale.

Spatial indicators. Hazard index Vulnerability index

FACTOR INDICATOR CATEGORY CH W

Socioeconomic status

Livelihood(0.396)

Labourers (% of unit)Informal workers (% of unit)Formal workers Skilled & highly educated workersTransferences from outside areas

B+B+C-C-C-

0.480.290.110.040.07

Income level(0.396)

Families Below Food Threshold (% unit)Families Below Poverty ThresholdFamilies Above Poverty Threshold

B+B+C-

0.610.280.11

Dependency ratio(0.117)

1 to 1 (% of unit)2 or 3 to 14 to 15 or more to 1

C-C-B+B+

0.060.120.260.56

Family size(0.07)

Less than 5 residents (% of unit)6 to 10 11 to 15More than 15

C-B+B+B+

0.060.120.260.56

Housing

House type(0.55)

Reinforced Brick-Concrete (% of unit)Semi-ConcreteLight materials class 1Light materials class 2Light Materials class 3

C-C-B+B+B+

0.030.060.130.260.53

Land ownership (0.45)Owned (% of unit)Rented-tenancySquatted, illegal occupation

C-B+B+

0.060.270.67

Facilities

Access to drinking water(0.60)

Private faucet (% of unit)Shared faucetBuy to Private FaucetPublic faucet and PumpPublic Pump

C-B+B+B+B+

0.040.090.150.300.42

Sanitary facilities(0.40)

Water sealed unit (% of unit)Shared unitOpen pitPublic toiletOther

C-B+B+B+B+

0.020.170.110.120.57

Environmental quality of surroundings

Waste disposal (0.40) Number of garbage accumulation spots B+ 0.40

stagnated waters (0.60)Percentage of the unit perennially occupied by stagnated waters

B+ 0.60

Economic opportunities

Topographic elevation of facilities with economic importance (0.67)

Commercial activities Transport-related activitiesMixed residential-small businessesAgriculture

0.290.210.210.100.05

Topographic elevation of Road Network (0.33)

Main road Secondary road Pathways

0.620.300.09

Community Capacities Topographic elevation of Facilities with social importance for the community(0.15)

Health services Institutional servicesEducational servicesReligious servicesAreas for recreationOpen spaces for institutional services

0.410.200.200.100.040.04

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Indicators1. Generic social vulnerability indicators:

Percentage of young children Percentage of elderly people Percentage of minority groups Percentage of single parent households Percentage of households living below poverty level. Literacy rate

2. Hazard specific social vulnerability indicators people located in flood risk zones, both a daytime and nighttime scenario people located in landslide risk zones, both a daytime and nighttime

scenario people located in technological risk zones, both a daytime and nighttime

scenario people located in seismic risk zones, both a daytime and nighttime

scenario

3. Hazard specific physical vulnerability indicators buildings located in flood risk zones, with different return periods buildings located in landslide risk zones, with different degree of

susceptibility to landslides buildings located in technological risk zones, with different degree of

susceptibility to landslides buildings located in seismic risk zones, with different intensities and

return periods

4. Capacity indicators Distance to Evacuation sites Distance to hospitals. Awareness

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Input data

This exercise uses the results of the loss estimation exercises done earlier for landslides, floods, earthquakes and technological hazards.

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Different levels of aggregation

• Districts• Wards• Census tracts• Mapping units

• City blocks• Basic units for

risk

• Building footprints

• Unemployment• Literacy rate

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Indicators1. Generic social vulnerability indicators:

Percentage of young children Percentage of elderly people Percentage of minority groups Percentage of single parent households Percentage of households living below poverty level. Literacy rate

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Indicators2. Hazard specific social vulnerability

indicators people located in flood risk zones, both a daytime and nighttime

scenario people located in landslide risk zones, both a daytime and

nighttime scenario people located in technological risk zones, both a daytime and

nighttime scenario people located in seismic risk zones, both a daytime and nighttime

scenario

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Steps in the exercise

Step 1: Generation in SMCE of a criteria tree for Generic Social Vulnerability Indicators, with the groups of factors.

Step 2: Generation in SMCE of a criteria tree for Hazard specific social vulnerability indicators, with the groups of factors related to population affected by earthquakes, landslides, flooding and technological disasters in a daytime, and nighttime scenario.

Step 3: Generation in SMCE of a criteria tree for Hazard specific physical vulnerability indicators, with the groups of factors related to buildings affected by earthquakes, landslides, flooding and technological disaster scenarios.

Step 4: Generation in SMCE of a criteria tree for Capacity indicators, which in this case are the distance to emergency centers (e.g. hospitals or fire stations) and the level of awareness.

Step 5: Combination of the 4 sets of indicators into an overall vulnerability indicator.

ISL 2004

SMCE process

Identification of the main goal. Identification of a hierarchy of sub goals. Identification of criteria or effects, which measure the

performance of the sub goals. Creating and filling a criteria tree, which represents the

hierarchy of the main goal, any sub goals, and the criteria.

Identification of alternatives to be evaluated. Assignment of input maps to criteria for each

alternative. Determination of a standardization method per criterion. Weighing of criteria in the criteria tree. Calculation of the Composite Index maps and

visualization. Classifying or slicing the Composite Index maps and

visualization. Calculation of Shape Index and/or Connectivity Index.

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The criteria tree

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The criteria tree

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Spatial multi-criteria analysis

A criteria tree contains all criteria

Factors: a criterion that contributes to a certain degree to the output

Benefits contributes

positively to the output; the more you have (the higher the values), the better it is

Costs contributes

negatively to the output; the less you have (the lower the values), the better it is

Constraints: criterion that determines in the calculation of the main goal .Mask out area

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Criteria tree: Generic Social Vulnerability

Generate Criteria Tree: Factors: Age related, Income Related,

Ethnicity related, Social structure Link with attributes in tables

Standardization Weighting Optional: constraint

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Standardization of criteria

Maximum: The input values are divided by the maximum value of the map

Interval: Linear function with the maximum and minimum values of the map

Goal: Linear function with a specified maximum and minimum values

Piecewise linear: Linear function with two breaking points located between the extremes

Convex: Convex function with one user defined value to re-shape the curve

Concave: Concave function with one user defined value to re-shape the curve

U-Shape: U-shape curve with one user defined value to stretch or shrink the curveGaussianBell-shape curve with one user defined value to stretch or shrink the curve

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How to select weights?

Direct estimation by expert The user has to specify weight values him/herself. These

user-defined weights are automatically normalized Pair-wise comparison

With a pairwise comparison matrix, each variable (or criterion) is compared to all others in pairs in order to evaluate whether they are equally significant, or whether one of them is somewhat more significant / better than the other for the goal concerned

Ranking method the criteria and variables are simply ranked according to

their importance as landslide controlling factors Source: ILWIS Multi Criteria Evaluation

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Criteria tree

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Criteria tree: Physical Vulnerability & capacity

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Final combination

The overall vulnerability indicator is made by combining the four indicator that we have calculated thus far: A. Generic_Social_Vulnerability

(exercise 8.1) B. Population_Vulnerability

(exercise 8.2) C. Physical_Vulnerability (exercise

8.3) Capacity (exercise 8.4)

Combine A,B,C with SMCEFinal Vulnerability := Vulnerability /

Capacity