بررسی تحولات کاربری اراضی شهرستان رشت با استفاده از آنالیز تصاویر ماهواره ای (مقاله علمی وزارت علوم)
درجه علمی: نشریه علمی (وزارت علوم)
آرشیو
چکیده
با توجه به تغییرات گسترده کاربری اراضی و ضرورت آگاهی مدیران و برنامه ریزان از چگونگی تحولات حاد ث شده برای سیاست گذاری و چاره اندیشی جهت رفع معضلات موجود، آشکارسازی تغییرات کاربری زمین ضروری به نظر می رسد. بنابراین نقشه کاربری اراضی یکی از الزامات هرگونه برنامه ریزی توسعه ملی و منطقه ای است که مدیران، برنامه ریزان و کارشناسان را قادر می سازد با شناسایی وضع موجود و مقایسه قابلیت ها و پتانسیل ها، در زمینه حل معضلات و رفع نیازهای حال و آینده اقدامات لازم را طراحی و اجرا نمایند. امروزه به دلیل هزینه بسیار زیاد تهیه نقشه های کاربری اراضی با روش های سنتی و دستی، سنجش از دور می تواند با دقت و سرعت بیشتری به مهندسان در تهیه نقشه کاربری اراضی و در مرحله بعد، ارزیابی تغییرات در منطقه کمک کند. هدف از این پژوهش، بررسی تحولات کاربری اراضی شهرستان رشت طی سال های 1369 الی 1399 با استفاده از تصاویر ماهواره ای لندست است. به منظور تجزیه و تحلیل داده ها از تصاویر در نر م افزار Google Earth Engine بررسی و نتایج حاصل در نرم افزار Arc GIS تحلیل و به صورت نقشه تولید گردید. بررسی ها نشان داد که در طول 30 سال مورد مطالعه، از درصد کاربری های جنگل و کشاورزی کاسته، در حالی که به درصد اراضی ساخته شده، اراضی زراعی و مراتع افزوده شده است. بیشترین افزایش را نیز کاربری های سکونتگاه (شهری و روستایی) با 8080 هکتار، و مرتع با 12690 هکتار را به خود اختصاص داده است.Investigating the Land Use Changes in the City of Rasht Using Satellite Image Analysis
Considering the extensive changes in land use and the necessity of providing awareness to managers and planners about the nature of these transformations for policy-making and problem-solving, the detection of land use changes through land cover analysis has become essential. Therefore, land use mapping is a requirement for any national and regional development planning. It empowers managers, planners, and experts to design and implement necessary actions by identifying current conditions, comparing capabilities and potentials, and addressing current and future needs and issues. Due to the high costs associated with traditional manual methods of land use mapping, remote sensing can offer engineers a faster and more accurate means for land use mapping and subsequent assessment of changes in an area. The present research aimed to investigate the land use changes in the city of Rasht from 1990 to 2020 using Landsat satellite images. Data analysis was conducted using Google Earth Engine, and the results were further analyzed and visualized using ArcGIS software. The findings indicated that over the 30-year study period, the percentage of forest and agricultural land decreased, while built-up areas, croplands, and pastures increased. The highest increase was observed in residential (urban and rural) land use, encompassing 8,080 hectares, followed by a 12,690-hectare expansion in pastureland. Extended AbstractIntroduction Having knowledge about the various land surface covers and human activities in different areas holds a significant importance as foundational information for various planning endeavors. One of the effective, valuable, and practical sources of information for identifying the land cover is remote sensing data. Remote sensing technology serves as an essential and valuable tool for assessing changes in land surface. To enhance efficiency in land use change detection, remote sensing is often integrated with Geographic Information Systems (GIS). The city of Rasht is situated in Guilān Province and stands out for its agricultural activities, particularly rice cultivation, ranking first in the country. Additionally, this region boasts pristine natural areas such as forests and pastures. Factors contributing to changes in land use within the region include population growth, the pressing need for housing, and the conversion of agricultural lands to residential for making profit. Amidst these circumstances, the main objective of this study is to investigate the land use changes in Rasht.MethodologyIn this current research, remote sensing science has been used to investigate the changes and transformations in land use and land cover within the city of Rasht. To analyze the data, images were examined using Google Earth Engine software, and the results were further analyzed in ArcGIS software, ultimately producing maps. For each year under study, the Normalized Difference Vegetation Index (NDVI) was derived from quarterly Landsat images and used as auxiliary data. The NDVI index quantifies vegetation coverage by measuring the difference between near-infrared and red wavelengths, which respectively reflect and absorb vegetation. This index was computed for four 3-month periods throughout the year.DiscussionThe changes that have occurred over a thirty-year period from 1990 to 2020 have been assessed based on available data. The images and analyses derived from change detection have revealed that the most prominent change, evident through a comparison of generated land use maps, is the continuous shift in land use patterns. This includes a reduction in forest and agricultural lands and an increase in residential and pasture lands. It's worth noting that the two classes of 'pasture' and 'bare land' should be considered cumulatively due to the fact that many areas of Guilān's soil rapidly transform into grasslands and pastures as a result of rainfall. Thus, the time of taking the satellite image and the corresponding weather conditions significantly influence the classification of these areas as either 'bare land' or 'pasture'. The extent of changes is as follows: from 1990 to 2020, the area of residential land use has increased by approximately 81 square kilometers, and the combined area of 'bare land' and 'pasture' classes has increased by around 170 square kilometers. In contrast, forest and agricultural lands have decreased by 11 and 236 square kilometers, respectively, during these years. The most significant changes in residential land use have occurred in areas that were previously designated for agriculture. This phenomenon can be attributed to the intermingling of agricultural and residential lands in the Guilān province.ConclusionThe analysis revealed that during the 30 years under study, the percentage of forest and agricultural land has decreased, while the percentage of residential and pasture/bare land use has increased. Many agricultural lands, specifically the rice fields, have been converted to residential areas, or they are left uncultivated and are identified as bare pastures in recent satellite images. Forest coverage within Rasht is limited, primarily concentrated in the southern region, particularly in the Sarāvān area. Given the conditions of these forests, the issue of forest degradation and the prevalence of pine logging in certain parts of the county have prevented a significant decline in this land category. The reduction in orchards and agricultural lands is a significant challenge in the current land use changes. Economic issues, the commercialization of properties, recent droughts, and water shortages that have led to a decline in agricultural income at both provincial and national levels are among the factors driving rural farmers to convert their land to residential use in order to generate income and liquid assets. This trend is evident in the increased area of residential and pasture/bare land use. Although, the analysis of residential land use changes indicates an increasing trend. In recent years, inflation, capital preservation, migration, and rising housing demand within the province have driven the construction of numerous houses, apartments, residential complexes, and government housing projects in the county. Furthermore, due to the region's tourism potential, villa construction has seen a significant rise in recent years, contributing to the increasing trend of residential land use.FundingThere is no funding support.Authors’ ContributionAuthors contributed equally to the conceptualization and writing of the article. All of the authors approved the content of the manuscript and agreed on all aspects of the work. Conflict of Interest Authors declared no conflict of interest.AcknowledgmentsWe are grateful to all the persons for scientific consulting in this paper.
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