• Title/Summary/Keyword: Getis-Ord G statistics

Search Result 6, Processing Time 0.02 seconds

An Application of Network Autocorrelation Model Utilizing Nodal Reliability (집합점의 신뢰성을 이용한 네트워크 자기상관 모델의 연구)

  • Kim, Young-Ho
    • Journal of the Economic Geographical Society of Korea
    • /
    • v.11 no.3
    • /
    • pp.492-507
    • /
    • 2008
  • Many classical network analysis methods approach networks in aspatial perspectives. Measuring network reliability and finding critical nodes in particular, the analyses consider only network connection topology ignoring spatial components in the network such as node attributes and edge distances. Using local network autocorrelation measure, this study handles the problem. By quantifying similarity or clustering of individual objects' attributes in space, local autocorrelation measures can indicate significance of individual nodes in a network. As an application, this study analyzed internet backbone networks in the United States using both classical disjoint product method and Getis-Ord local G statistics. In the process, two variables (population size and reliability) were applied as node attributes. The results showed that local network autocorrelation measures could provide local clusters of critical nodes enabling more empirical and realistic analysis particularly when research interests were local network ranges or impacts.

  • PDF

A Spatial Statistical Approach to the Delimitation of CBD (도심경계설정을 위한 공간통계학적 접근)

  • Kim, Ho-Yong;Kim, Ji-Sook;Lee, Sung-Ho
    • Journal of the Korean Association of Geographic Information Studies
    • /
    • v.15 no.4
    • /
    • pp.42-54
    • /
    • 2012
  • The main purpose of this study is to suggest the spatial statistical approach suitable for the delimitation of Busan CBD. For this purpose, Getis-Ord $G_i^*$ and both of IDW (Inverse Distance Weight) and FDB(Fixed Distance Band) were applied to delimit the CBD boundary. And then, the results of the CBD boundary were compared and verified with the methodologies of the previous studies. The result of IDW accorded with the previous study relating to the delimitation of the boundary of CBD, and the result of FDB was reflecting the characteristics of the mixed-use residential of a transition zone. As a result of the land use quotient, the mixed land use of residential and commercial was highly specialized in the boundary of FDB. These results will be able to support the understanding of urban spatial structure and the effective CBD management.

Classification of Regional Types for Pinus densiflora stands Using Height-DBH Growth in Korea (우리나라 소나무림의 수고-흉고직경 생장에 따른 지역형 분류)

  • Park, Joon Hyung;Jung, Su Young;Lee, Kwang Soo;Kim, Chang Hwan;Park, Yong Bae;Yoo, Byung Oh
    • Journal of Korean Society of Forest Science
    • /
    • v.105 no.3
    • /
    • pp.336-341
    • /
    • 2016
  • The object of this study was to classify the local types in relation to regional differences using Height-DBH growth of Pinus densiflora in Korea. The regional types were clustered according to Getis-Ord's $G_i$ among Local indicators of spatial association (LISA) by characteristics of spatial distribution which were calculated the residual of sample plots by fitting Height-DBH growth model using Weibull growth equation. Accordingly, Pinus densiflora were classified 3 groups, It indicated that annual precipitation had one of the biggest impacts among the considered site and climate factors. This results can become the standard for regional management of Pinus densiflora forests.

Exploratory Spatial Data Analysis (ESDA) for Age-Specific Migration Characteristics : A Case Study on Daegu Metropolitan City (연령별 인구이동 특성에 대한 탐색적 공간 데이터 분석 (ESDA) : 대구시를 사례로)

  • Kim, Kam-Young
    • Journal of the Korean association of regional geographers
    • /
    • v.16 no.5
    • /
    • pp.590-609
    • /
    • 2010
  • The purpose of the study is to propose and evaluate Exploratory Spatial Data Analysis(ESDA) methods for examining age-specific population migration characteristics. First, population migration pyramid which is a pyramid-shaped graph designed with in-migration, out-migration, and net migration by age (or age group), was developed as a tool exploring age-specific migration propensities and structures. Second, various spatial statistics techniques based on local indicators of spatial association(LISA) such as Local Moran''s $I_i$, Getis-Ord ${G_i}^*$, and AMOEBA were suggested as ways to detect spatial dusters of age-specific net migration rate. These ESDA techniques were applied to age-specific population migration of Daegu Metropolitan City. Application results demonstrated that suggested ESDA methods can effectively detect new information and patterns such as contribution of age-specific migration propensities to population changes in a given region, relationship among different age groups, hot and cold spot of age-specific net migration rate, and similarity between age-specific spatial clusters.

  • PDF

Analysis on Change Characteristics of Spatial Structure Related with Urban Planning : Using Spatial Statistical Method (도시계획과 연계한 공간구조의 변화 특성 분석 - 공간통계기법을 이용하여)

  • Seo, Kyung-Min;Kim, Ho-Yong;Lee, Sung-Ho;Kwon, Tae-Ho
    • Journal of the Korean Association of Geographic Information Studies
    • /
    • v.17 no.2
    • /
    • pp.1-14
    • /
    • 2014
  • In this study, the change characteristics of urban spatial structure in Daegu were analyzed connecting with urban planning for efficient urban management. Urban development process from 1970 to 2010 in Daegu was analyzed utilizing Getis-Ord $G_i^*$ methodology, a spatial statistical method, and it was identified that Daegu was in the stage of disurbanization. However, as Daegu orients multi-nuclei city, it was difficult to explain the stage of urban development after disurbanization in 2000. Accordingly, to analyze detailed changes in spatial structure in multi-centric areas after 2000, population, land price and employment factor changes were analyzed using Bachi Measurement. According to analytical results, multi-centralization process has been continued in Daegu. Urban core area and Chilgok area showed spatial structure change into distribution process, Ansim area into concentration process, and Seongseo and Talseo area into concentration and distribution process. Therefore, urban planning considering the regional characteristics are needed for efficient urban management.

Health Assessment of the Nakdong River Basin Aquatic Ecosystems Utilizing GIS and Spatial Statistics (GIS 및 공간통계를 활용한 낙동강 유역 수생태계의 건강성 평가)

  • JO, Myung-Hee;SIM, Jun-Seok;LEE, Jae-An;JANG, Sung-Hyun
    • Journal of the Korean Association of Geographic Information Studies
    • /
    • v.18 no.2
    • /
    • pp.174-189
    • /
    • 2015
  • The objective of this study was to reconstruct spatial information using the results of the investigation and evaluation of the health of the living organisms, habitat, and water quality at the investigation points for the aquatic ecosystem health of the Nakdong River basin, to support the rational decision making of the aquatic ecosystem preservation and restoration policies of the Nakdong River basin using spatial analysis techniques, and to present efficient management methods. To analyze the aquatic ecosystem health of the Nakdong River basin, punctiform data were constructed based on the position information of each point with the aquatic ecosystem health investigation and evaluation results of 250 investigation sections. To apply the spatial analysis technique, the data need to be reconstructed into areal data. For this purpose, spatial influence and trends were analyzed using the Kriging interpolation(ArcGIS 10.1, Geostatistical Analysis), and were reconstructed into areal data. To analyze the spatial distribution characteristics of the Nakdong River basin health based on these analytical results, hotspot(Getis-Ord Gi, $G^*_i$), LISA(Local Indicator of Spatial Association), and standard deviational ellipse analyses were used. The hotspot analysis results showed that the hotspot basins of the biotic indices(TDI, BMI, FAI) were the Andong Dam upstream, Wangpicheon, and the Imha Dam basin, and that the health grades of their biotic indices were good. The coldspot basins were Nakdong River Namhae, the Nakdong River mouth, and the Suyeong River basin. The LISA analysis results showed that the exceptional areas were Gahwacheon, the Hapcheon Dam, and the Yeong River upstream basin. These areas had high bio-health indices, but their surrounding basins were low and required management for aquatic ecosystem health. The hotspot basins of the physicochemical factor(BOD) were the Nakdong River downstream basin, Suyeong River, Hoeya River, and the Nakdong River Namhae basin, whereas the coldspot basins were the upstream basins of the Nakdong River tributaries, including Andong Dam, Imha Dam, and Yeong River. The hotspots of the habitat and riverside environment factor(HRI) were different from the hotspots and coldspots of each factor in the LISA analysis results. In general, the habitat and riverside environment of the Nakdong River mainstream and tributaries, including the Nakdong river upstream, Andong Dam, Imha Dam, and the Hapcheon Dam basin, had good health. The coldspot basins of the habitat and riverside environment also showed low health indices of the biotic indices and physicochemical factors, thus requiring management of the habitat and riverside environment. As a result of the time-series analysis with a standard deviation ellipsoid, the areas with good aquatic ecosystem health of the organisms, habitat, and riverside environment showed a tendency to move northward, and the BOD results showed different directions and concentrations by the year of investigation. These aquatic ecosystem health analysis results can provide not only the health management information for each investigation spot but also information for managing the aquatic ecosystem in the catchment unit for the working research staff as well as for the water environment researchers in the future, based on spatial information.