Exercise 4 - Pokhara Region
|  | Pokhara is the capital of the Nepalese district of Kaski | |
Pokhara is the capital of the Nepalese district of Kaski. Being that its location is near Annapurna and Dhaulagiri, tourism has become an important part of the economy of the region.
As a result of this, the town has grown significantly during recent decades.
See table:
| Year | Inhabitants |
| 1971 | 20,610 |
| 1981 | 46,640 |
| 1991 | 95,310 |
| 2001 | 197,681 |
Remote sensing methods can be used to monitor developments of this type. However, the Pokhara region is a good example, showing both the potential and the difficulties involved in remote sensing methods.
It is not easy to delineate the city of Pokhara in the well-enhanced near-natural colour Landsat TM image of the year 2000. The spectral properties of the city rooves are similar to those of the surrounding surfaces. However, the structures within a city can be identified by the human eye. Structures that are comparable with streets and squares can also be found in the environment - for instance dry river beds. An initial, rapid conclusion is that the buildings and streets consist of natural materials found in the area around Pokhara.
This is one of the challenges remote sensing is facing. How can an automated system identify these almost invisible differences? There are some methods used to solve this problem, for example systems which identify structures within the satellite image. Another possibility is the use of additional sensors, resolutions and multitemporal data.
An additional problem is the mountainous area. Large areas are hidden in the shadow of high mountains, making it difficult to assess these areas.
Nevertheless, we will try to analyse the Pokhara region in a number of steps and using various methods with the LEOWorks image processing software.
Visual Image Analysis
Open the three near real-natural colour images of the Pokhara region (with the number 3 in the name) in LEOWorks:
anapurna_landsat_1972_SE_band_231.tif
anapurna_landsat_1979_SE_band_231.tif
anapurna_landsat_2000_SE_band_321.tif
Compare the images in terms of seasonal changes (vegetation), resolution, altitude of the sun (shadows) and land cover.
Name the differences and similarities.
Find features such as lakes, airports, rivers, the city of Pokhara and clouds in all three images.
Have a closer look at the 1979 and 2000 images. Which shapes on the ground look similar?
What do they relate to?
Are the same features identifiable in the 1972 image?
In which respect do we find differences in the way the city appears in the three images? Can you explain the reason?
Open the infrared false-colour image anapurna_landsat_2000_SE_band_432.tif.
Compare this image with the near-natural colour image from the same year (2000).
How do the colours differ?
Which feature appears in red in the false-colour infrared image and why?
Which features can be identified more easily in the infrared false-colour image than in the near-natural colour image? Explain the reasons.
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