The aim of this paper is to analyse, using GIS and remote sensing techniques, the land use/cover change of the city of Dej, in order to explore the spatial and temporal characteristics and the consequences of urbanization trends of the past 250 years. We used a wide range of data, including historical maps and Landsat images from 1984 to 2017. In order to identify the land-use change, we used supervised classification and change detection methods. Analysing the obtained data, we could conclude the fact that, between 1763 and 1990, the area was characterized by a significant urban sprawl and land-use change, due to the economic development and political views (the urban border area increased from 1.2 km2 to 13.72 km2), but after 1990, the suburbanization process has begun, due to the economic failure, having a 13.85% built-up area increase towards S-SE and N direction, constrained by hydrological and geomorphological factors.
DISCUSSIONS AND CONCLUSIONSBased on the results of this study, we can confirm that, the urbanization process has significantly modified the land-use between the 1763 and 2017 period. We successfully combined GIS and remote sensing techniques in order to calculate the rate and the tendency of land-use change, and the urban sprawl of the investigated area.With the help of the historical maps, supervised classification and change-detection techniques, we could identify the factors that changed the land-use of the study area: in the 18 th century, due to the city's particular setting, Dej became a market town, therefore, the urban border area had grown by 116.66% and the forest lands decreased by 47.29%; in 1881, the railway infrastructure had developed, leading to the development of the city's economy, having, as consequence an increase of 20.76% urban area; after the Second World War, new industries appeared, therefore. population migration had begun and the urban border area has increased significantly by 281.11% and the forest lands had decreased dramatically by 82.05%; after 1990, the suburbanization process of the city has begun, caused by new political, social and economic contexts introduced in Romania; due to the economic loss and the attraction of the rural sites, the built-up area has increased by 13.85% in the S-SE and N direction, near the northern communication roads; the forest lands were characterized by stagnation. Using Lakshmana's formula, we could predict the fact that, in the future, the city of Dej will unite with the neighbouring villages, having a 47% built-up area increase.The Someș River bed, due to several floods, changed drastically, therefore, it was necessary to deviate and drain some of the river's arms. Due to this fact, the urban sprawl has a south-southeast orientation, bypassing the river bed direction.The information obtained with remote sensing and GIS techniques are essential in order to understand the causes of land-use change in the city of Dej, and can be used for further landplanning strategies and hazard mitigation works, in order to have a sustainable u...