Evaluation of the Built-Up Area Dynamics in the First Ring of Cluj-Napoca Metropolitan Area, Romania by Semi-Automatic GIS Analysis of Landsat Satellite Images

Bogdan-Eugen Dolean,Ștefan Bilașco,Ciprian Moldovan,Iuliu Vescan,Sanda Roșca,Dănuț Petrea,Ioan Fodorean

doi:10.3390/app10217722

Bogdan-Eugen Dolean, Ștefan Bilașco + Show 5 more

Open Access

https://doi.org/10.3390/app10217722

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Journal: Applied sciences	Publication Date: Oct 31, 2020
Citations: 15	License type: CC BY 4.0

Affiliation: Babeș-Bolyai University, Romanian Academy

Abstract

The accentuated dynamics of the real estate markets of the last 20 years, determined that a large part of the territories in the immediate vicinity of the big urban centers, to change their category of land use, in an accelerated rhythm. Most of the time, the land use changes according to the market requirements, the predominantly agricultural lands being occupied by constructions with residential or industrial functions. Identifying these changes is a difficult task due to the heterogeneity of spatial databases that come from different real estate development projects, so determining and implementing new methods to track land changes are currently highly required. This paper presents a methodologically innovative index-based approach for the rapid mapping of built-up areas, using Landsat-5, Landsat-7, and Landsat-8 satellite imagery. The approach described in this study differs from other conventional methods by the way the analysis was performed and also by the thematic indices used in the processes of built-up area delineation. The method, structured in a complex model, based on Remote Sensing and GIS techniques, can be divided into three distinct phases. The first stage is related to the pre-processing of the remote sensing data. The second stage involves the calculation of the normalized difference vegetation index (NDVI), the modified normalized difference water index (MNDWI), and the bare soil index (BI) correlated with the extraction of all areas not covered by vegetation; respectively, the elimination from the result of all areas covered by water, bare land, or uncultivated arable land. The result of this stage is represented by a distinct thematic layer that contains only built-up areas and other associated territories. The last step of the model is represented by the validation of the results, which was performed based on statistical methods and also by direct comparison with field reality, obtaining a validation coefficient which is generally above 85% for any of the methods used. The validation process shows us that by applying this method, the fast mapping of the built-up areas is significantly enhanced and the model is suitable to be implemented on a larger scale in any practical and theoretical application that aims at the rapid mapping of the built-up areas and their evolutionary modeling.

Highlights

Urban areas have expanded at an accelerated speed during the last five decades, and rates of urban population growth are higher than the overall growth in most countries [1,2,3]
The implementation of remote sensing indices using Landsat Level1 satellite images provides good results in terms of built-up areas delineation, the results being useful in the process of spatial planning and issuing public policies for the harmonious development of the territory
The analysis of the quantitative data obtained from the exploitation of the digital databases, resulting from the implementation of the proposed model, highlights a very high dynamic for the entire analyzed period (2000–2019), of the built territory afferent to Flores, ti ATU and Apahida ATU; dynamics explained by the location of those two ATUs on the east-west development axis of Cluj-Napoca city, the axis dictated by the morphology of the place that constitutes the corridor of the Somes, ul Mic river

Summary

Introduction

Urban areas have expanded at an accelerated speed during the last five decades, and rates of urban population growth are higher than the overall growth in most countries [1,2,3]. The accelerated development of urban areas and the anthropic pressure on the natural environment is becoming more and more prevalent recently due to population growth, resource depletion, and a modern, service-oriented economy. This has brought about many negative environmental repercussions to the world; for example, less precipitation, more dryness, higher temperatures [4,5], and increasing the probability of man-made landslides [6,7,8,9]. Built-up area delineation is a common challenge in terms of monitoring urban development and measuring urban sprawl. Urban environment and built-up area delimitation are subjects frequently approached in the European Union documents: EEA Report No

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