Key Words: Urban, Ger, Building Parcels, Multi-Temporal, RS, GIS
Abstract
The aim of this study is to investigate the urban changes that have occurred in central part of Ulaanbaatar area, Mongolia over the past few decades and describe the socio-economic reasons for the changes. For this purpose, multi-temporal RS and GIS data sets are used. For the analysis, two classes such as ger area (a Mongolian national house) and building parcels are selected and compared.
Introduction
In recent years, cities all over the world have experienced rapid growth because of the rapid increase in world population and the irreversible flow of people from rural to urban areas. Specifically, in the larger towns and cities of the developing world the rate of population increase has been constant and nowadays, many of them are facing unplanned and uncontrolled settlements at the densely populated sites or fringes. To prevent from such occasions urban planners need detailed updated maps for thorough planning and management. However, most city planners have a lack of such maps and often they posses old data which is not relevant for current decision making. Even if they do not hold a detailed updated map of the city area a regularly updated map with an acceptable resolution can at least give them an impression about the changes in the city area [3,4,5,7].
Mongolia, as many of the developing countries has a problem with the urban expansion and the growth of population in the main cities. For example, over the last decades Ulaanbaatar, the capital city of Mongolia has significantly expanded due to different development activities and migration of people from rural sites [7]. Various changes have been and are being occurred in the city but there are no regularly updated maps to indicate those changes. In general, it should be interesting to study the urban growth in the capital city comparing the growths occurred before 1990 when Mongolia had centralized economy with the changes occurred during the market economy.
The aim of this paper is to detect the main changes occurred in central part of Ulaanbaatar area before and after 1990 and describe the socio-economic reasons of these changes. For this purpose, multi-temporal RS and GIS data sets have been used. For the study, two classes such as ger area (a Mongolian national house), and building parcels (parcels of apartments, residential houses and industrial buildings) have been selected and compared. The analysis was carried out using ERDAS and ILWIS-systems and different RS and GIS techniques have been applied.
The GER
Mongolian dwellings have evolved with nomadic life. The need for a portable dwelling is obvious for people following their herds and seeking new pastures. The history of the Mongol ger goes back to about 2500-3000 B.C. and has continued to be used to the present day. The ger is still used as dwelling everywhere in Mongolia. The walls of the ger are made of narrow birch willows formed into a lattice framework and held together by leather strips. Sections of the lattice are put together in a large circle to form the walls. Each section is approximately five to six feet high and seven to eight feet long. The entire outside surface of the ger is covered with felt, tied in place by ropes made of hair and wool. One layer is sufficient in the summer season. Two or three layers are necessary in winter. The ger is comfortable in all kinds of weather. In hot summer, the root wheel is opened and the felt walls are raised to give ventilation. When it is windy the ger is stable becuase of its shape and is tied to the ground and in cold winter the layers of the left are increased and the door is sealed. The assembling and taking down of any ger are done within half an hour in as fixed order. The gers situated in urban areas are surrounded by fences, whereas the gers of herdsmen in
rural sites do not have fences because they move from place to place following good pasture area. The gers of rural herdsmen are shown in figure1.
Figure 1. The gers of rural herds people
As a test site Ulaanbaatar, the capital city of Mongolia has been selected. Ulaanbaatar is situated in the central part of Mongolia on the river Tuul at a height of 1350 m above sea level and currently has approximately 650,000 inhabitants [7]. The city is surrounded by mountains which are spurs of the Hentii range. The temperature of Ulaanbaatar is about 20-25°C above zero in summer but in winter it is usually 15-20°C below zero. The mean precipitation in the city is 233 mm [8].
Data Sources
- A topographic map of 1969, scale1:25.000
- SPOT XS image of 1986
- SPOT PAN data of 1990
- SPOT XS image of 1997
- Census data of Ulaanbaatar.
