INTERNATIONAL INSTITUTE FOR GEO-INFORMATION SCIENCE AND EARTH OBSERVATION

Flood Hazard Assessment: ILWIS Case study.

Drs. Nanette C. Kingma

Generalized physiographic map.

From: Geological map of Bangladesh, 1990.

Flood map Bangladesh.

Extreme flooding: 1988.

1987 : Dry Season.

SPOT band 1

1987 dry-season

SPOT band 3

1987 dry-season

SPOT band 2

1987 dry-season

Moderate Flood 1987

SPOT band 1

1987 flood SPOT band 2

1987 flood SPOT band 3

1987 flood

Severe flood 1988

SPOT band 1

1988 flood SPOT band 2

1988 flood SPOT band 3

1988 flood

Overview

DRY 87

FL 88

MFL 87

Why band ratio’s

Clouds Shadows

Band Ratio DRY 1987.

Brdry87:

Band ratio: band3/band1 dry-87.

Band Ratio Moderate Flood 1987

Brmfl87:

Band ratio: band3/band1 mfl-87.

Band Ratio Severe Flood 1988

Brfl88:

Band ratio: band3/band1 flood-88.

Slicing of Brdry87 into land and water.

Dry87wl:

Slicing into water and land of band ratio 3/1 dry 87.

Slicing of Brmfl87 into land and water.

Slicing into water and land of band- ratio 3/1 mfl-87 .

Slicing of Brfl88 into land and water.

Fl88wl:

Slicing into water and land of band- ratio 3/1 flood88 .

Cross operation result: dry87wl and mfl87wl .

Cross dry87wl and mfl87wl output map Dryfl.

Crossing of: DryFl with fl88wl.

Final result map Crossing of: dry87wl, mfl87wl, and fl88wl.

Bangladesh: Confluence Ganges - Meghna.

Cross table: maps drywl-mfl87wl

Cross table:final map drymflcr - fl88wl.

Bangladesh: Confluence Ganges - Meghna.

Final result map crossing of: dry87wl, mfl87wl, and fl88wl; with legend.

Map Layout.