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| | | | | | | Exercise 3 - The summer monsoon and its floods - Continued
| | SPOT-X image of Bangladesh before the 1988 floods | |
Flooded environment
Download the LANDSAT TM images of Bangladesh of 1989 and 2000.
The two GeoTIFFs show a part of Bangladesh just North-West of the confluence of the Ganges and Bramhaputra rivers in November 1989 and 2000. The LANDSAT TM images have a ground resolution of 150 m/pixel. The image size is 1008 x 950 pixels.
How many kilometres do the images cover?
Download the images and save them in a folder called 'Bangladesh'.
| | SPOT-X image of Bangladesh after the 1988 floods | |
The shape files show cities, main roads, railways and other useful features in the part of Bangladesh covered by the two images. The shape files and the images fit together, because the same projection has been used for the pixel and vector data.
Download the shape files and save them in your folder 'Bangladesh'.
| | | Landsat TM image of Bangladesh taken in 1989 |
Open the programme ArcExplorer and choose Theme>Add Theme. Switch to the folder "Bangladesh" and select the images and shape files:
- ganges2000_mix_ts.tif
- ganges1989_mix_ts.tif
- rivers_utm.shp
- waterbodies_utm.shp
- traffic_utm.shp
- cities_utm.shp and
- boundary_utm.shp
The shape file properties need to be changed in order to resemble a topographic map. Double click the first layer 'BOUNDARY_UTM' in the Legend. A pop up menue opens. Change the Color to 'yellow', the Style to 'Dash dot dot line' and the Size to '2'.
| | ArcExplorer window | |
The second layer 'CITIES_UTM' consists of two types, the 'city' type and the 'town' type. Both types or classes will have a different appearance. To change the properties, double click 'CITIES_UTM' in the Legend. Choose Unique Values in Classification options and select Type in Field.
The two classes 'city' and 'town' appear in Discrete values and symbols. Change the properties by clicking the symbol and change the class "city" to a 'square marker size 10' and the class 'town' to 'a circle marker size 8'.
The class 'TRAFFIC_UTM' also consists of different types, 'main road', 'main railway' and 'railway'. Change the properties as described before and choose an 'orange solid line size 4' for main roads, a 'black solid line size 4' for main railways and a 'black dash line size 3' for railways.
| | | ArcExplorer : Theme properties |
Change the properties for 'WATERBODIES_UTM' and 'RIVERS_UTM' to a blue polygon and a blue solid line size 2.
Activate the second image GANGES2000_MIX_TS.TIF and deactivate the shape file WATERBODIES_UTM and the first image GANGES1989_MIX_TS.TIF.
Compare both images while activating and deactivating the image GANGES1989_MIX_TS.TIF and answer the following questions:
How does the vegetation cover change?
Why does the vegetation cover change even though both images were taken in November?
How do the courses of the rivers, especially the Ganges, change?
What problems appear while mapping the river system, due to changes in the watercourse?
Which cities and towns seem to be endangered by floods?
Find out the names of the cities and towns by choosing Tools>Identify. Then click the icon MapTips and select 'ADMIN_NAME'. Mark the city or town with the pointer and read the name.
What other objects are endangered by floods? What does that mean for the people living in endangered zones?
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| | Himalaya IntroductionBackgroundExercises IntroductionManual exercisesStudy of water vapour in the atmosphereThe summer monsoon and its floodsLinks Meteosat imagesWeather broadcast worldwideClimate systemCAREDLR - Basemapping
of DhakaEduspace - Software LEOWorks 3ArcExplorerEduspace - Download Climate zones (PDF)Climate diagrams (PDF)Temperature and precipitation diagrams (PDF)Ready-made diagrams (PDF)Himalayas water vapour images (ZIP)SPOT XS images of Bangladesh (ZIP)Landsat images of Bangladesh (ZIP)Shape files for Bangladesh (ZIP)Map of climate zones
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