vulnerability mapping for disaster assessment...
TRANSCRIPT
Vulnerability Mapping for Disaster Assessment Using
ArcGIS Tools and Techniques for Mumbai City, India
Reshma Raskar-Phule
Assistant Professor, Department of Civil Engineering,
Sardar Patel College of Engineering,
Andheri (w), Mumbai – 400058, India.
Also,
Research Scholar, Department of Civil Engineering,
Indian Institute of Technology (IIT) Bombay,
Powai, Mumbai – 400076, India.
Overview
• Hazard, Vulnerability and RISK Analysis (HVRA)
- Terminologies on Disaster Risk Reduction - (UNISDR 2009)
• Vulnerability Assessment
• ArcGIS
- Data Collection
- Data Analysis
- Mapping
• Vulnerability- Hazard Maps
Overview
• Mumbai City
• 437.71 sqkm area
• 11.9 million population
• Vulnerable to natural disasters
• Data Collection
• Qualitative data
• Primary and secondary sources
• Spatial data – location and geometry
• ArcGIS - Open Street Map (OSM)
• 721 data grid points generated
Maharashtra Mumbai
Location Map of Mumbai city
Data and Technology used
Source: ArcGIS
Spatial Data – Download OSM Data Download
Spatial Data Analysis:
• Grid Layer - 1 km X 1 km -
- Clipped with digitized Mumbai boundary layer
- Exact area of each grid - Calculate geometry tool
• Vulnerability Index (VI)
𝐕𝐈𝐢 =(𝐕𝐢−𝐕𝐦𝐚𝐱)
(𝐕𝐦𝐚𝐱−𝐕𝐦𝐢𝐧)
- VIi is the vulnerability index for the indicator pertaining to the ith grid,
- Vi is the vulnerability value of the ith grid.
- length in case of transportation infrastructure and
- count of the indicators within a grid in case of critical infrastructure
- Vmax and Vmin are the maximum and minimum vulnerability values
of all the grid cells 1 km X 1 km Grid layer Clipped
with digitized Mumbai Boundary
layer
Methodology
Methodology
1. Layers - Infrastructure indicators
- Transportation indicators - railways,
aeroways, roadways and bridges
- Critical facilities indicators - schools,
hospitals, important Government
offices, hotels, fire stations, heritage
structures, railway stations, bus
stations and depos and educational
institutions
2. Intersect –
Grid Layer and Indicator layer
•
Length of the indicator in
each grid is calculated
using the clip and
intersect tools from the
ArcToolbox
Number of indicator in
each grid is counted using
the spatial join tool of
Overlay from the
ArcToolbox
Methodology
Transportation Infrastructure vulnerability using ArcGIS
1) Infrastructure layer is imported into GIS;
2) Length of each indicator is contained in the attributes
table
3) The infrastructure indicator segments from the attribute
table are selected which fall within and intersect a
particular grid
4) The “statistics” option from the “length” field in the
attribute table options is selected
5) The program calculates the sum of lengths and display
them in that particular grid
6) The values are stored in a table and finally used for
determining the vulnerability indices.
Vulnerability grid map for Roads
Results
Vulnerability grid maps
Vulnerability index of each grid is scaled
from 0 to 1.
Railways Educational Buildings
Vulnerability
Level
Vulnerability
Index (VI)
Infrastructure density
No 0 No infrastructure
Low 0.25 Low infrastructure
Moderate 0.5 Moderate infrastructure
High 0.75 Dense infrastructure
network
Very High
or Critical
1 Very dense
infrastructure network
Vulnerability Classes based on VI
Results
Hazard x Exposure x Vulnerability = Disaster Risk
X X =
Hazard Exposure Vulnerability Risk
Conclusion
• ArcGIS can be a powerful tool for carrying out
- Hazard- vulnerability studies of urban areas and
- Create awareness of the vulnerability of an area to natural hazard.
• Present study demonstrates the capability of the ArcGIS tools to carry out
vulnerability assessment considering various options.
• The results are generated in the form of color-coded maps depicting the grid wise
vulnerability index.
• These maps can be combined with hazard potential maps to obtain Hazard-
Vulnerability-Risk maps that can be used by the stakeholders, policy makers,
planners and engineers to identify the areas with potentially heavy damage and to
assess the extent of damage so that the disaster management plans for the city can
be strengthened.
Discussion/ Q&A