• Title/Summary/Keyword: Moran's index

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Application of Bivariate Spatial Association for the Quantitative Marine Environment Pattern Analysis (정량적인 해양환경패턴 분석을 위한 이변량 공간연관성 적용)

  • Hwang, Hyo-Jung;Choi, Hyun-Woo;Kim, Tea-Rim
    • Journal of the Korean Association of Geographic Information Studies
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    • v.11 no.1
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    • pp.155-166
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    • 2008
  • The quantitative bivariate spatial pattern analysis was applied for the water quality and nutrients data of Masan Bay, and for this analysis Pearson's r as aspatial correlation measurement, Moran's I as spatial association measurement and L index as integration of aspatial and spatial measurement methods were used. To understand the aspatial and spatial characteristics implicated in L index, Pearson's r as well as Moran's I were classified into 3 types respectively, and Pearson's r and Moran's I were combined with 9 types, and also quantile of L index value was used for each of those 9 types. Finally, these types were defined as 5 groups having not overlapped L index range. According to the application result of L index groups, bivariate water quality and nutrients showed no aspatial correlation regardless of spatial association in February and July, but they showed aspatial correlation having clustered spatial pattern in May and November. The result of this study providing the guideline for the interpretation of aspatial correlation and spatial association using L index is expected to be helpful for the marine environment pattern analysis using quantitative index for further study.

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Identifying Spatial Distribution Pattern of Water Quality in Masan Bay Using Spatial Autocorrelation Index and Pearson's r (공간자기상관 지수와 Pearson 상관계수를 이용한 마산만 수질의 공간분포 패턴 규명)

  • Choi, Hyun-Woo;Park, Jae-Moon;Kim, Hyun-Wook;Kim, Young-Ok
    • Ocean and Polar Research
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    • v.29 no.4
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    • pp.391-400
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    • 2007
  • To identify the spatial distribution pattern of water quality in Masan Bay, Pearson's correlation as a common statistic method and Moran's I as a spatial autocorrelation statistics were applied to the hydrological data seasonally collected from Masan Bay for two years ($2004{\sim}2005$). Spatial distribution of salinity, DO and silicate among the hydrological parameters clustered strongly while chlorophyll a distribution displayed a weak clustering. When the similarity matrix of Moran's I was compared with correlation matrix of Pearson's r, only the relationships of temperature vs. salinity, temperature vs. silicate and silicate vs. total inorganic nitrogen showed significant correlation and similarity of spatial clustered pattern. Considering Pearson's correlation and the spatial autocorrelation results, water quality distribution patterns of Masan Bay were conceptually simplified into four types. Based on the simplified types, Moran's I and Pearson's r were compared respectively with spatial distribution maps on salinity and silicate with a strong clustered pattern, and with chlorophyll a having no clustered pattern. According to these test results, spatial distribution of the water quality in Masan Bay could be summed up in four patterns. This summation should be developed as spatial index to be linked with pollutant and ecological indicators for coastal health assessment.

The Changes in the Quality of Life Measure of the Seoul Metropolitan Area (수도권 삶의 질 지수 변동에 관한 연구)

  • Lee, Se-Hyung;Chang, Hoon;Rho, Jin-A
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.29 no.1
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    • pp.29-37
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    • 2011
  • The purpose of this research is to measure Quality of Life indices using Factor Analysis and Principle Component Analysis and to analyze the spatial patterns of Quality of life distribution in the Seoul Metropolitan Area in terms of spatial association using spatial statistics and spatial exploratory technique. In order to check the degree of clustering, this study used spatial autocorrelation indices, global Moran's I index. In addition, local scale analysis was conducted using Moran Scatterplot and Local Moran's I to identify the spatial association pattern and the high Quality of life. The analysis based on global statics showed that, in the Seoul Metropolitan Area, QoL Indices had been distributed with positive spatial association. According to the local spatial statistics, the general tendency of clustering H-H clusters which were mainly concentrated on the Seoul, L-H clusters were concentrated on the Kyunggi-Do and L-L Clusters showed the regional extent of lagging behind. However, in case of H-H, L-H Clusters they had been spread out in the Newtown as population increase.

Analysis of Relation Between Criminal Types and Spatial Characteristics in Urban Areas (도심지역의 범죄 종류와 공간적 특성 관계분석)

  • Cha, Gyeong Hyeon;Kim, Kyung Ho;Son, Ki Jun;Kim, Sang Ji;Lee, Dong Chang;Kim, Jin Young
    • Journal of Satellite, Information and Communications
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    • v.10 no.1
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    • pp.6-11
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    • 2015
  • In this paper, we analyzed current states and spatial characteristics of crime occurring in A city of Colombia using big data of crime. The analysis draws on the crime statistics of Colombia National Police Agency from 2013 January to September. We also investigated spatial autocorrelation of crime using global and local Moran's Index. Spatial autocorrelation analysis shows significant spatial autocorrelation in the high frequency of crime. Global Moran's I analysis indicates that there are statistically significant value of crime area. Using local Moran's Index analysis, we also implement Local Indicators of Spatial Association(LISA) map and hot spot analysis helps us identify crime distribution.

A Time-Series Analysis of Landscape Structural Changes using the Spatial Autocorrelation Method - Focusing on Namyangju Area - (공간자기상관분석을 통한 시계열적 경관구조의 변화 분석 - 남양주지역을 대상으로 -)

  • Kim, Heeju;Oh, Kyushik;Lee, Dongkun
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.14 no.3
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    • pp.1-14
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    • 2011
  • In order to determine temporal changes of the urban landscape, interdependence and interaction among geo-spatial objects can be analyzed using GIS analytic methods. In this study, to investigate changes in the landscape structure of the Namyangju area, the size and shape of landscape patches, and the distance between the patches were analyzed with the Spatial Autocorrelation Method. In addition, both global and local spatial autocorrelation analyses were conducted. The results of global Moran's I revealed that both patch size and shape index transformed to a more dispersed pattern over time. Next, the local Moran's I of patch size in all time series determined that almost all patches were of a high-low pattern. Meanwhile, the local Moran's I of the shape index was found to have changed from a high-high pattern to a high-low pattern in time series. Finally, as time passes, the number of hot spot patches about size and shape index had been decreased according to the results of hot spot analysis. These changes appeared around the development projects in the study area. From the results of this study, degradation of landscape patches in Namyangju were ascertained and their specific areas were delineated. Such results can be used as useful data in selecting areas for conservation and for preparing plans and strategies in environmental restoration.

An Analysis on the Spatial Pattern of Local Safety Level Index Using Spatial Autocorrelation - Focused on Basic Local Governments, Korea (공간적 자기상관을 활용한 지역안전지수의 공간패턴 분석 - 기초지방자치단체를 중심으로)

  • Yi, Mi Sook;Yeo, Kwan Hyun
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.39 no.1
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    • pp.29-40
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    • 2021
  • Risk factors that threaten public safety such as crime, fire, and traffic accidents have spatial characteristics. Since each region has different dangerous environments, it is necessary to analyze the spatial pattern of risk factors for each sector such as traffic accident, fire, crime, and living safety. The purpose of this study is to analyze the spatial distribution pattern of local safety level index, which act as an index that rates the safety level of each sector (traffic accident, fire, crime, living safety, suicide, and infectious disease) for basic local governments across the nation. The following analysis tools were used to analyze the spatial autocorrelation of local safety level index : Global Moran's I, Local Moran's I, and Getis-Ord's G⁎i. The result of the analysis shows that the distribution of safety level on traffic accidents, fire, and suicide tends to be more clustered spatially compared to the safety level on crime, living safety, and infectious disease. As a result of analyzing significant spatial correlations between different regions, it was found that the Seoul metropolitan areas are relatively safe compared to other cities based on the integrated index of local safety. In addition, hot spot analysis using statistical values from Getis-Ord's G⁎i derived three hot spots(Samchuck, Cheongsong-gun, and Gimje) in which safety-vulnerable areas are clustered and 15 cold spots which are clusters of areas with high safety levels. These research findings can be used as basic data when the government is making policies to improve the safety level by identifying the spatial distribution and the spatial pattern in areas with vulnerable safety levels.

Hotspot Analysis of Korean Twitter Sentiments (한국어 트위터 감정의 핫스팟 분석)

  • Lim, Joasang;Kim, Jinman
    • Journal of Korea Multimedia Society
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    • v.18 no.2
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    • pp.233-243
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    • 2015
  • A hotspot is a spatial pattern that properties or events of spaces are densely revealed in a particular area. Whereas location information is easily captured with increasing use of mobile devices, so is not our emotion unless asking directly through a survey. Tweet provides a good way of analyzing such spatial sentiment, but relevant research is hard to find. Therefore, we analyzed hotspots of emotion in the twitter using spatial autocorrelation. 10,142 tweets and related GPS data were extracted. Sentiment of tweets was classified into good or bad with a support vector machine algorithm. We used Moran's I and Getis-Ord $G_i^*$ for global and local spatial autocorrelation. Some hotspots were found significant and drawn on Seoul metropolitan area map. These results were found very similar to an earlier conducted official survey of happiness index.

Spatial Distribution Pattern of the Populations of Camellia japonica in Busan (부산 사하구 동백나무 집단의 공간적 분포 양상)

  • Kang, Man Ki;Huh, Man Kyu
    • Journal of Life Science
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    • v.24 no.8
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    • pp.813-819
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    • 2014
  • The spatial distribution of geographical distances at five natural populations of Camellia japonica in Busan, Korea was studied. The four plots (Mollundae, Gadeok-do, Du-do, and Jwiseum) of C. japonica were uniformly distributed in the forest community and only one plot (Amnam-dong) was aggregately distributed in the forest community. Morisita index is related to the patchiness index showed that the plot $20m{\times}50m$ had an overly steep slope when the area was larger than $20m{\times}20m$, which indicated that the degree of aggregation increased significantly with increasing quadrat sizes, while the patchiness indices did not change from the plot $5m{\times}10m$ to $10m{\times}10m$. The spatial structure was quantified by Moran's I, a coefficient of spatial autocorrelation. Ten of the significant values (76.9%) were positive, indicating similarity among individuals in the first 4 distance classes (80 m), i.e., pairs of individuals with dissimilarity characteristics can separate by more than 100 m.

Study on the Delineation of City-Regions Based on Functional Interdependence and Its Relationships with Urban Growth (기능적 상호작용에 따른 도시권 설정과 성장관계에 대한 연구)

  • Kim, Dohyeong;Woo, Myungje
    • Journal of Korea Planning Association
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    • v.54 no.7
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    • pp.5-23
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    • 2019
  • The central government has implemented policies to strengthen the competitiveness of small and medium sized cities for balanced development at the national scale. However, since it is often difficult to enhance the competitiveness through partial projects of each jurisdiction, many local governments collaborate at the regional scale. This suggests that a regional approach is important for the management of small and medium sized cities. On the one hand, the concept of network city suggests that various functional networks can affect the growth of small and medium sized cities. Given this background, the purposes of this study are to delineate regional boundaries at national scale and identify their relations of growth by using functional network and Moran's I index. The study uses the Markov-chain model and cluster analysis to delineate the regions, and Moran's I is employed to identify the relations of growth. The results show that interactions between jurisdictions through networks could be crucial factors for growth of small and medium sized cities, while the networks based on passenger travel and freight movement have different implications. The results suggest that policy makers should not only consider local level investments, but also take the characteristics of networks between cities into account for achieving balanced development and developing regeneration policies.

Spatial Aggregation on the Main Producing Area of Nontimber Forest Products (단기소득 임산물의 주산지 집적도에 관한 연구)

  • Byun, Seung Yeon;KOO, Ja-Choon
    • Journal of Korean Society of Forest Science
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    • v.110 no.1
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    • pp.106-115
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    • 2021
  • The aim of the study was to analyze the spatial characteristics of the main producing areas of nontimber forest products. We analyzed the spatial aggregations of the main producing area and their changes using the Moran's I index. We found that 45% of nontimber forest products were significanty spatially clustered. Additionally, in five major products, we observed that the main producing area has expanded and the degree of aggregation has also strengthened over the last ten years. The results of this study can be effectively used for forest policies, such as determining the location and size of the distribution centers of specific forest products.