Abstract
The spread of cities poses a serious urbanisation and natural challenge and significantly affects thequality of life of the inhabitants. The aim of the study was to examine the possibility of analysingthe spread of the city of Sieradz based on the interpretation of multi-temporal aerial imagery fromthe years 1959, 1996 and 2015, and the topographical object database. There are 22 land cover classesthat are attributed with coefficients determining their degree of belonging to the urban use of space.The area of the city is divided into hexagonal primary fields (1 ha) and the proportion of different formsof land use is determined and the M indicator calculated, which determines to what extent each primaryfield belongs to the urban way of space use. The primary fields were than classified into three zones:urban (0.5 < M ≤ 1.0), transitional (0.3 ≤ M ≤ 0.5) or rural (0 ≤ M < 0.3). Maps of the increment of thisindicator in the test periods were made also. In the city there were consistently predominant areas witha rural nature of space use, because Sieradz has a large share of farmland, grassy vegetation, woodlandand trees, orchards, plantations and gardens. Over time, however, the city area of typical urban useis increasing, which is mainly in the central and eastern part of the city and is clearly approaching itssouthern border, confirming the expansion of urban development to peripheral areas. By the year 1996the growth of the M indicator took place mainly in the central part of the city, and in the next periodrevealed the clear “islands” of this growth quite distant from the centre. During the period 1959–1996 inSieradz an early stage of the development of urban sprawl is noticeable – mainly progressive constructionnear the railway. However, in later years, the increase in accessibility to car transport was the causeof a deeping phenomenon of “urban sprawl” into the peripheral areas, causing a lively developmentof the suburbs. Studies have shown that urban sprawl also applies to mid-sized cities and confirmsthe suitability of archive aerial imagery and studies made using fuzzy sets theory to analyse the urbansprawl. The method used is relatively simple to use and can be fully automated.