High resolution Space Imagery for the Assessment of Urban Vulnerable Areas

2nd Japan-Peru Workshop on Earthquake Disaster Mitigation

Lima - Peru, March 13, 2007

Miguel Estrada

Universidad Nacional de Ingeniería

Kyoto University

ウニベルシダヅ ナシオナル デ インヘニエリア

What we need to Identify?

Vulnerable locations in urban areas to be prepared for a disaster or retrofit the existing buildings located in dangerous places.

Is it Possible to use Satellite Images?

Cover a vast area of land

There is historical imagery

Periodical acquisition (4th dimension)

Spectral Information (5th dimension)

Various satellites on orbit

Reasonable price?

Ikonos Satellite

Commercial SatelliteResolution of 4m and 1m4 spectral bands1 panchromatic band1 scene 165 km2

Short return periodCapacity of obliqued vision

Satellite Image of Lima(12.1x14.6km aprox.)

PhD. Ing. Miguel Estrada Mendoza

Sensors

Each material on the Earth shows a characteristic way to reflect or emit electromagnetic energy.The sensors onboard of satellites can “feel” the strength of this reflected of emitted energy.

PhD. Ing. Miguel Estrada Mendoza

Since satellite imagery are made of Numbers (digital numbers)

PhD. Ing. Miguel Estrada Mendoza

Using Spectral InformationBanda 1

Banda 2

Banda 3

Banda 4

PhD. Ing. Miguel Estrada Mendoza

How To Process the Information

Conversion A/Dde analog imagery

Conversion D/DSatellite images

Digital Information (images)

Radiometric Correction

Geometric Correction

Transformation Classification

Analog output Digital database

Image Input

Pre-processing

Output Image

Processing

ProblemDefinition

Mejoramiento de imágenesTrue True ColorColor ~ 4~ 4.0.0mm

Bands 3, 2 and 1 (RGB)Bands 3, 2 and 1 (RGB)Improved Improved Color Color ImageImagePanchromatic Panchromatic ImageImage 11..00mm

Mejoramiento de imágenes

Phase 1:Identification

Phase 2:Video

Phase 3:Video

Phase 4:Video

Phase5: Video

Spectral Analysis

Pseudo Infrared Colour Image

Normalized Differenced Vegetation Index

),(),(

),(),(j)(i,

jiji

jiji

RNIR

RNIRNDVI

+

−=

Cluster Analysis

Middle Resolution Satellite Image

Conclusions

Satellite imagery can give a general idea about the social and economic distribution in an urban area.Social and economic condition could provide an idea on the quality of housings.Spectral analysis can be used to automate the assessment and evaluation of urban areas.Further analysis on the roof´s spectral response could be give further details.Middle resolution satellite images also could investigated for the urban inventory issues.