IOP Conference Series: Earth and Environmental Science PAPER • OPEN ACCESS Analysis on the Characteristics of Cultivated Land Change in DianChi Lake Basin based on remote sensing image processing technonlogy in the past 20 years To cite this article: Min Gao et al 2021 IOP Conf. Ser.: Earth Environ. Sci. 658 012006 View the article online for updates and enhancements. This content was downloaded from IP address 170.106.35.234 on 27/09/2021 at 04:07 3rd International Forum on Geoscience and Geodesy IOP Publishing IOP Conf. Series: Earth and Environmental Science 658 (2021) 012006 doi:10.1088/1755-1315/658/1/012006 Analysis on the Characteristics of Cultivated Land Change in DianChi Lake Basin based on remote sensing image processing technonlogy in the past 20 years Min Gao1,4, Yi Luo3,4, Lina Shi1, and Chunxue Shang2,4* 1 School of Information Science and Technology, Yunnan Normal University, Yunnan, 650500, China 2 Dean’s Office, Yunnan Normal University, Yunnan, 650500, China 3 Faculty of Geography, Yunnan Normal University, Yunnan, 650500, China 4 GIS Technology Research of Resource and Environment in Western China, Ministry of Education, Yunnan Normal University, Yunnan, 650500, China *Corresponding author’s e-mail: [email protected] Abstract. Cultivated land is the fundamental guarantee of agricultural production, accurate acquisition of information such as the area and distribution of cultivated land and the change characteristics of cultivated land is of great significance for agricultural resource monitoring and production. The development of remote sensing technology provides a new technical scheme for rapid and efficient extraction of cultivated land information. This article takes Dianchi Lake Basin as the research object to study the characteristics of cultivated land changes in Dianchi Lake Basin in the past 20 years. In the past 20 years, the distribution of cultivated land in the dianchi lake basin gradually changed from species concentration to decentralization, and showed a trend of gradually moving away from dianchi lake. Through the analysis of the dynamic attitude of land use, it is found that the cultivated land area in the dianchi basin has significantly changed between the land use in the past 20 years. From the perspective of the change trend and state index of single land use in the dianchi lake basin, the bidirectional transition of all land use in the region is frequent and extremely unbalanced. The area converted from cultivated land to non- cultivated land is larger than the area converted from non-cultivated land to this type. It develops towards the direction of scale reduction and is in the state of "falling trend". 1. Introduction Cultivated land is the foundation of agriculture and the entire national economy. The use of cultivated land is one of the key issues affecting the sustainable development of the region[1]. By analyzing the change law of cultivated land and its influencing factors, it can provide a theoretical basis for the dynamic balance and regulation of cultivated land in the region, help realize the sustainable use of cultivated land in the region, and has important significance for the study of the relationship between cultivated land protection and economic development.The relationship is important[2-4]. And the change of cultivated land also affects the change of impervious area in this area[5]. International research on land use changes officially began with the "Agenda 21" formulated by the United Nations in 1992. The "Agenda 21" formulated by the United Nations in 1992 marked the official beginning of international land use change research[6]. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Published under licence by IOP Publishing Ltd 1 3rd International Forum on Geoscience and Geodesy IOP Publishing IOP Conf. Series: Earth and Environmental Science 658 (2021) 012006 doi:10.1088/1755-1315/658/1/012006 Kunming's current rapid economic development and rapid population growth are the key reasons for the reduction of cultivated land in the Dianchi Lake Basin. Analyzing the change trend of cultivated land and the impact of urbanization development on cultivated land change can provide a reference for policy formulation. This study mainly uses satellite data of the Dianchi Lake Basin in the past 20 years to extract the cultivated land in the Dianchi Lake Basin, uses ENVI and ArcGIS software to analyze the temporal and spatial characteristics of the cultivated land changes in the Dianchi Lake Basin in the past 20 years, and provides a scientific basis for the formulation of government planning and development decision-making plans. 2. Study area and method 2.1. Study area The Dianchi Lake Basin is located in the middle of the Yunnan Plateau, in the three watershed areas of the Yangtze River, the Pearl River and the Red River. The drainage area is 2920 km2. The basin covers the Panlong River and Wuhua District in Kunming City, and most of the Guandu District, Jinning District and Chenggong District. The center of the basin is 1895 meters above sea level. It has a low- latitude plateau mountain monsoon climate. There is no severe cold in winter and no heat in summer. The annual average temperature is 15.1℃, the average annual rainfall is 1,075 mm, the average annual sunshine is 2,200 hours, and the frost-free period is more than 240 days. It is suitable for farming. The topography of the basin is generally high in the north and low in the south, with a long and narrow basin shape from north to south. For a long time, under the control of the address structure and other factors, an asymmetric stepped landform pattern with Dianchi as the center, wide on the south, north and east, and narrow on the west has been formed. 2.2. Data source and processing In the research process of this paper, Landsat series satellite images are used as the data basis. The Landsat series of remote sensing satellite data are downloaded from the official website of the United States Geological Survey (USGS). The Dianchi Lake Basin covers two sceneries. The strip numbers are 129/042 and 129/043 respectively. Due to the influence of natural factors such as climate, summer is selected as the remote sensing satellite image research season. In order to maximize the extraction accuracy, the image should be summer and cloudless remote sensing images. Choose a date when the cloud cover is less than 5%, and the image has no cloud cover, which is convenient for identifying and extracting cultivated land. The image acquisition dates are as shown in table 1: Table.1 Cloud-free image acquisition time. Year Statellite and sensor types Date Stripe 1999 Landsat-5 TM 1.24 129/(42、43) 2001 Landsat-7 ETM+ 6.14 129/(42、43) 2004 Landsat-5 TM 3.10 129/(42、43) 2008 Landsat-5 TM 4.6 129/(42、43) 2010 Landsat-5 TM 2.7 129/(42、43) 2013 Landsat-8 OLI/TIRS 4.20 129/(42、43) In this paper, the commonly used FLAASH model is used for radiometric correction of remote sensing images. This module has been integrated into the ENVI 5.3 and can be used directly. This method has high accuracy.Since the Dianchi Lake Basin in the study area is in the strip number 129/042, 129/043, the images need to be cropped and spliced, and the histogram matching method is used to splice the two images of each year. 2 3rd International Forum on Geoscience and Geodesy IOP Publishing IOP Conf. Series: Earth and Environmental Science 658 (2021) 012006 doi:10.1088/1755-1315/658/1/012006 2.3. Research methods 2.3.1. Cultivated land extraction There are traditionally two methods for classification of mainstream remote sensing images: visual interpretation classification and computer automatic classification. This research uses computer automatic classification. Computer automatic classification is usually divided into two forms: unsupervised classification and supervised classification. In the image accuracy evaluation, it is mainly used to compare the classification result with the actual measured value, and the accuracy of the classification result can be displayed in a confusion matrix. The confusion matrix is calculated by comparing the position and classification of each measured pixel with the corresponding position and classification in the classified image. 2.3.2. Dynamic analysis method of cultivated land conversion According to the interpretation results of remote sensing images, the land use/cover Conversion Matrix model is used to analyze the direction and scale of land use/cover change transfer. The dynamics of land use/cover change are commonly expressed by three mathematical models: △ △ 1 100% (1) Where: ∆U_out is the sum of the areas of a land use/cover type converted to other types during the study period T, ∆U_in is the sum of the areas converted from other types to this type, and U_a is a certain land use/ The area of the cover type, T is the study period, when T is set to year, RS is the average annual rate of change of a certain land use/cover type. △ △ 1 100% (2) Where: △, △, and T are the same as above, and Rss is the degree of spatial change of a certain land use/cover type. △ △ 1 1 (3) △ △ Where: △ and △ are the same as above, and Ps is the change trend and state index of a certain land use/cover type. 3. Results and analysis 3.1. Inspection of extraction accuracy The overall accuracy of supervised classification and unsupervised classification are 93.8% and 80.8%, respectively, and the kappa coefficients are 0.845 and 0.552, respectively.