4 research outputs found
Google Earth Engineμ μ΄μ©ν λΆνμ μ°λ¦Ό ν©νν μ°κ΅¬
νμλ
Όλ¬Έ(μμ¬) -- μμΈλνκ΅λνμ : λμ
μλͺ
κ³Όνλν μνμ‘°κ²½Β·μ§μμμ€ν
곡νλΆ(μνμ‘°κ²½ν), 2021.8. μ΄λκ·Ό.μ°λ¦Ό ν©ννλ μ°λ¦Ό μνκ³λ₯Ό νκ΄΄νλ©° λ¬Ό μ μ₯ λ° κ³΅κΈκ³Ό λκΈ°μ€μΌμ μ€μ΄λ λ± μ°λ¦Όμ΄ κ°μ§κ³ μλ κΈ°λ₯μ μ νμν¨λ€. ν©ννλ‘ μΈν μ°λ¦Όμ κΈ°λ₯ μ νλ κΈ°νλ³ν λμ λ° λκΈ°μ§ μΈ‘λ©΄μμ λΆμ μ μΈ μν₯μ λ―ΈμΉκ² λλ€. λΆνμ μΈκ³ 3κ° μ°λ¦Ό ν©νμ§μμΌλ‘ 1990λ
λλΆν° μ΅κ·ΌκΉμ§ μ°λ¦Όμ μ½ 28%κ° ν©ννλμλ€λ κ΅λ¦½ μ°λ¦Ό κ³Όνμμ μ°κ΅¬κ²°κ³Όκ° μλ€. νμ§λ§ 곡μΈλ ν΅κ³λ μμ΄ μΆν 볡μμ μν΄μλ μ νν νν© νμ
μ΄ νμν μ€μ μ΄λ€. μΌλ°μ μΈ μ°λ¦Ό ν©ννμλ λ¬λ¦¬ λΆνμ κ²½μ μ μΈ μ΄λ €μμΌλ‘ μΈν μλ λΆμ‘±κ³Ό μλμ§ μμμ λΆμ‘±μΌλ‘ λ°μνμλ€. μλ 곡κΈμ μνμ¬ μ°λ¦Όμ λ°μΌλ‘ κ°κ°λμκ³ , μνμ λΆμ‘±μΌλ‘ μΈνμ¬ μλμ§μμΌλ‘ μ¬μ©νκΈ° μν 무λΆλ³ν λ²λͺ©μ΄ μ§νλμ΄ κ΄λ²μν¨ μ°λ¦Ό ν©ννκ° κ°μνλμλ€. μ°λ¦Ό ν©ννμ λ¬Έμ μ μ λΆνμμλ μΈμνμ¬ κ΄λ ¨ μ μ±
μ μ§ννλ λ±μ λ
Έλ ₯μ νμμ§λ§, μ§μλλ κ²½μ λκ³Ό νκ΅κ³Όμ κ΄κ³ μ
νλ‘ μΈνμ¬ ν¨κ³Όμ μΌλ‘ μ΄λ£¨μ΄μ§μ§ μκ³ μλ€. λΆνμ μ°λ¦Ό ν©ννλ λΆνλΏ μλλΌ νλ°λμ νκ²½κ³Ό λλΆμμ μ¬ν κ²½μ μ μΌλ‘ μν₯μ μ£Όκ³ μκΈ° λλ¬Έμ 볡μμ΄ μκΈν μν©μ΄λ©° μΆν νκ΅κ³Όμ κ΄κ³κ° κ°μ λμμ λ ν¨κ³Όμ μΈ λ³΅μ μ¬μ
μ§μμ μν΄μλ μ νν νν©κ³Ό κ·λͺ¨λ₯Ό νμ
νλ κ²μ΄ μ€μνλ€. λΆνμ νμ¬ μ κ·Ό λΆκ° μ§μμΌλ‘ νμ₯μ‘°μ¬λ₯Ό ν΅ν νν© νμ
μ΄ λΆκ°λ₯νκΈ° λλ¬Έμ μμ±μμμ μ¬μ©ν μ격νμ¬κ° κ°μ₯ ν¨κ³Όμ μΈ λ°©λ²μ΄λ€. λν μ°λ¦Ό ν©ννλ λ¨κΈ°κ°μ λνλλ νμμ΄ μλλΌ μ₯κΈ°κ°μ κ±Έμ³ μ§νλλ νμμ΄κΈ° λλ¬Έμ λ€μ€μκΈ°λ‘ λΆμν νμκ° μλ€. λ°λΌμ λ³Έ μ°κ΅¬μμλ λΆνμ μ°λ¦Ό ν©ννκ° μ¬νλκΈ° μμν 1990λ
λ μ΄νμΈ 2000λ
λΆν° κ°μ₯ μ΅κ·ΌμΈ 2020λ
κΉμ§ 20λ
λμμ λΆν μ°λ¦Ό ν©νν νν©μ νμ
νλ κ²μ κΈ°λ³ΈμΌλ‘ λ κ°μ§ μ°κ΅¬ κ°μ€μ μΈμ 리λ₯Ό νμΈνκ³ , ν©νν μ§νμ΄ μΌλ§λ λμλμ§, 볡μμ¬μ
μ μ±κ³Όκ° μμλμ§ μ΄ν΄λ³΄κ³ μ νλ€. μ΄λ₯Ό ν΅ν΄ μΆν 볡μ μ¬μ
μ μ§νν λ, 체κ³μ μΈ κ³νμ μΈμΈ μ μλ κΈ°μ΄μλ£λ‘ μΈ μ μλλ‘ νλ κ²μ΄ μ°κ΅¬ λͺ©νμ΄λ€. μ΄λ₯Ό μνμ¬ λ―Έκ΅μ μ§λ¦¬μ 보 νλ«νΌμΈ Google Earth Engineμ ν΅νμ¬ ν½μ
κΈ°λ° κ°λ
λΆλ₯ λλ€ ν¬λ μ€νΈ(Random Forest) λ°©λ²μ μ¬μ©νμ¬ ν μ§ νΌλ³΅ λΆλ₯λ₯Ό μ§ννκ³ , μ΄λ₯Ό κΈ°λ°μΌλ‘ Change Detection(λ³ν κ°μ§)μ νμ¬ μ΄λ μ§μμμ ν©ννκ° μ§νλμλμ§, μ°λ¦Ό λ©΄μ μ΄ μΌλ§λ λ³ννμλμ§ μ΄ν΄λ³΄μλ€. λΆμμ μ§νν κ²°κ³Ό, 2000λ
-2010λ
λμ λΆνμ μ°λ¦Ό λΉμ¨μ μ 체 λ©΄μ μ μ½ 72.5%μμ μ½ 61%λ‘ μ½ 11.5% μ λ κ°μν κ²μΌλ‘ λνλ¬λ€. μ΄μ λ°λ©΄μ λμ§μ λμ§μ λΉμ¨μ κ°κ° μ½ 7%, μ½ 2% μ¦κ°ν κ²μΌλ‘ λνλ 무λΆλ³ν λ²μ±μ κ°κ°μΌλ‘ μΈν μ°λ¦Ό ν©ννκ° μ¬κ°νλ€λ κ²μ 보μ¬μ€λ€. λ³νκ° κ°μ₯ λ§μ΄ λνλ μ§μμ νμλ, ν¨κ²½λ, κ°μλ μ§μμΌλ‘ λνλ¬μΌλ©°, λ³νκ° κ°μ₯ μ κ² λνλ μ§μμ ν©ν΄λ μ§μμΌλ‘ λνλ¬λ€. 2010λ
-2020λ
λμμ λΆνμ μ°λ¦Ό λΉμ¨μ μ½ 61%μμ μ½ 62%λ‘ μ½ 1%μ λ μ¦κ°νμμΌλ©°, λμ§λ μ½ 3% μ¦κ°νμλ€. μ΄μ λ°λ©΄μ λμ§ λΉμ¨μ μ½ 4% κ°μνμ¬ λ³Έκ²©μ μΈ μ°λ¦Ό 볡μ μ¬μ
μ μμν 2016λ
μ΄ν μ°λ¦Ό λΉμ¨μ΄ μ½κ° μμΉνκ³ λμ§ λΉμ¨μ΄ κ°μνμμΌλ λμ§ λΉμ¨μ΄ μ¦κ°ν κ²μΌλ‘ 보μ μ°λ¦Ό 볡μμ΄ μ±κ³΅μ μΌλ‘ μ΄λ£¨μ΄μ§μ§ μμμΌλ©°, 무λΆλ³ν κ°κ° λν μ§μλκ³ μλ€λ κ²μ 보μ¬μ€λ€. λ³νκ° κ°μ₯ ν¬κ² μΌμ΄λ μ§μμ ν©ν΄λ, ν¨κ²½λ κ°μλ μ§μμΌλ‘ λνλ¬μΌλ©°, λ³νκ° κ°μ₯ μ κ² μΌμ΄λ μ§μμ νμλ μ§μμΌλ‘ λνλ¬λ€. 20λ
λμ 곡ν΅μ μΌλ‘ λ³νκ° λ§μ΄ μΌμ΄λ μ§μμ ν¨κ²½λ κ°μλλ‘, λΆμκ²°κ³Όλ₯Ό ν΅ν΄ μ΄ μ§μμμ κ°κ°κ³Ό λ²μ±κ° λ§μ΄ μΌμ΄λ¬μμ μ μ μλ€.Deforestation destroys forest ecosystems and reduces the functions of forests, such as reducing water storage and supply and air pollution. The degradation of forests due to deforestation harms climate change response and air quality. North Korea is one of the world's three deforested areas, and according to the research results of the National Institute of Forestry and Science, about 28% of the forest has been degraded from the 1990s until recently. However, as there are no official statistics, it is necessary to accurately identify the current situation for future restoration. Unlike general deforestation, North Korea was caused by a shortage of food and energy resources due to economic difficulties. Forests were cleared into fields for food supply, and extensive deforestation was accelerated by indiscriminate logging for use as an energy source due to a lack of coal. Although North Korea has recognized the problem of deforestation and implemented related policies, it has not been effectively implemented due to the continuing economic difficulties and deterioration of relations with South Korea. Since deforestation in North Korea has a socio-economic impact on North Korea and the environment on the Korean Peninsula and in Northeast Asia, restoration is urgently needed. In addition, it is important to know the exact current status and scale of deforestation for effective restoration project support when relations with Korea improve in the future. Since North Korea is currently inaccessible and it is impossible to determine the current situation through field surveys, remote sensing using satellite imagery is the most effective method. In addition, since deforestation is not a short-term phenomenon, but a long-term phenomenon, it is necessary to analyze it in multiple periods. Therefore, in this study, the status of deforestation in North Korea for 20 years from 2000 to 2020 after the 1990s, when deforestation in North Korea began to intensify, was identified, and two research hypotheses were established and confirmed. This study aims to enable it to be used as basic data for systematic planning when conducting a restoration project in the future. To this end, land cover classification is carried out using the pixel-based supervised classification random forest method through Google Earth Engine, a geographic information platform in the United States, and based on this, change detection is performed to determine the extent of devastation in an area. We looked at the progress and how much the forest area had changed. As a result of the analysis, the proportion of forests in North Korea decreased by about 11.5% from about 72.5% of the total area to about 61% from 2000 to 2010. On the other hand, the ratio of cropland and bareland increased by about 7% and about 2%, respectively, indicating that the deforestation caused by reckless logging and clearing is serious. The regions with the most changes were Pyeongan-do, Hamgyeong-do, and Gangwon-do, and the region with the least change was Hwanghae-do. During 2010-2020, the proportion of forests in North Korea increased by about 1% from about 61% to about 62%, and the cropland also increased by about 3%. When the full-scale forest restoration project began in North Korea, the ratio of bareland decreased by about 4% and the ratio of the forest increased slightly. Hwanghae-do and Gangwon-do, Hamgyeong-do showed the largest change, and Pyeongan-do show the least change. Gangwon-do, Hamgyeong-do, has seen many changes in common over the past 20 years, and the analysis results show that clearing and logging took place a lot in this area.Chapter 1. Introduction 2
1.1. Study Background and Purpose of Research 2
Chapter 2. Literature Review 5
2.1. Deforestation of North Korea 5
2.2. Random Forest using GEE 9
2.3. Change Detection 12
Chapter 3. Materials and Methods 14
3.1. Study Area and Materials 14
3.1.1. Study Area 14
3.1.2. Materials 15
3.2. Methods 21
3.2.1. Dataset and Pre-processing 21
3.2.2. Random Forest using GEE 22
3.2.3. Change Detection 23
Chapter 4. Results and Discussions 24
4.1. Results of Radom Forest 24
4.2. Results of Change Detection 28
4.2.1. 2000-2010 28
4.2.2. 2010-2020 30
4.2.3. 2000-2020 32
4.2.4. Regional Results 33
4.3. Discussions 46
Chapter 5. Conclusion 48
Bibliography 50
Abstract in Korean 55μ
A novel change detection approach for multi-temporal high-resolution remote sensing images based on rotation forest and coarse-to-fine uncertainty analyses
In the process of object-based change detection (OBCD), scale is a significant factor related to extraction and analyses of subsequent change data. To address this problem, this paper describes an object-based approach to urban area change detection (CD) using rotation forest (RoF) and coarse-to-fine uncertainty analyses of multi-temporal high-resolution remote sensing images. First, highly homogeneous objects with consistent spatial positions are identified through vector-raster integration and multi-scale fine segmentation. The multi-temporal images are stacked and segmented under the constraints of a historical land use vector map using a series of optimal segmentation scales, ranging from coarse to fine. Second, neighborhood correlation image analyses are performed to highlight pixels with high probabilities of being changed or unchanged, which can be used as a prerequisite for object-based analyses. Third, based on the coarse-to-fine segmentation and pixel-based pre-classification results, change possibilities are calculated for various objects. Furthermore, changed and unchanged objects identified at different scales are automatically selected to serve as training samples. The spectral and texture features of each object are extracted. Finally, uncertain objects are classified using the RoF classifier. Multi-scale classification results are combined using a majority voting rule to generate the final CD results. In experiments using two pairs of real high-resolution remote sensing datasets, our proposed approach outperformed existing methods in terms of CD accuracy, verifying its feasibility and effectiveness