THE GROWTH OF BUILT-UP AREAS AND CHANGE OF SHAPE INDEX OF THREE BIG CITIES IN THE HUNGARIAN GREAT PLAIN

Abstract

The expansion of Hungarian big cities and the growth of their built-up areas have been the central issue of several studies in the past decades. The objective of this paper is to describe the growth of built-up areas in three big cities in the Hungarian Great Plain, namely Debrecen, Nyíregyháza and Kecskemét. In the early development of these cities natural attributes were relevant too, however, in later phases merely social and economic factors influenced the cities’ growth. Military survey maps and other topographical maps from the 18th century onwards have been used for this study. Old maps have been georeferenced in order to be comparable with more recent maps. We have digitalized the built-up areas, out if which only the adjacent ones or those in close vicinity have been taken into account, disregarding distant boondocks. Assisted by GIS software, we calculated the area and the perimeter of cities’ built-up areas. According to the data it may be ascertained that the built-up areas of Debrecen, Kecskemét and Nyíregyháza have increased 13-18-fold between the 18^th and 21^st centuries. The perimeter of built-up areas has increased even more considerably (16-30-fold).

Various indices have been developed for the transformation of cities’ area, however, in this study we applied a landscape ecology-index too. In landscape ecology the so-called shape index shows the extent of stability of a homogenous plant patch, and to what extent it can be “contaminated” by other plant species. Circle-shaped patches are the most stable, while elongated ones are unstable. With this index the shape of establishments can be characterized, too.

In the 18^th century the studied cities were compact, their shapes similar to circles, with a shape index of 1.1-1.5. Houses were located inside the city walls, hardly any edifices to be found outside of them. In the 19^th century constructions took place outside of the city walls too and further off boondocks were set up. The shape index increased to 2.3-6.8. In the 20^th century factories were built on the edge of the cities and new housing areas were erected nearby the more significant roads. The shape index increased to 6.1-9.3.

In earlier times compact settlements were more defensible, and it is still cheaper to maintain the infrastructural network of a compact settlement nowadays, due to shorter roads and shorter wire- and sewage systems. In case of such settlements the interface with non-urban areas is smaller and so the environment pollution is less significant.