|
|
Exercise 3 - The summer monsoon and its floods - Continued 
A more effective method would be to display the extent of flooding on top of the 1987 image. This is the way helpers on the field estimate endangered areas, to assist when making decisions during disaster management.
Digitalise the main river bed. When you are done, choose Edit>Stop Edit to stop drawing. Save the shapefile in your folder 'Monsoon'.
Download ArcExplorer (see link in right navigation bar).
Choose Theme>Add Theme.... Choose the folder Monsoon and select the image bangladesh_870109.tif. Now select the vector-file Flood.shp produced in LEOWorks. Both files appear in the ArcExplorer Local box. Tick the boxes to the left of the filenames. Double click on the file Flood in the Local box. Choose Cross fill for Style and change the colour to blue. The extension of the flood is now merged with the 87 SPOT XS image. The variation between low and high water levels is visualised, and an enormous difference can be seen. The consequences of this type of flooding are easy to envisage, particularly if they take place in densly populated areas.
What are the reasons for the heavy floods, apart from the Monsoon itself? Search the Internet for answers.
Try to find out: Where heavy floods have appeared and/or might appear in the future? What kind of precautions are taken - discuss the advantages and disadvantages of each? How the annual floods affect life in those areas? What happens if the floods fail to appear? How many people have been affected by flooding in the Asian region over the past 10 years? Compare the number with the population of your home country. Last update: 18 April 2013
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
