• Title/Summary/Keyword: Zonal Statistics

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A Geomorphic Surface Analysis Using Remote Sensing in DMZ of Chugaryeong Rift Valley, Central Korea (위성영상을 이용한 추가령열곡 DMZ 지역의 지형면 분석)

  • LEE, Min-Boo
    • Journal of The Geomorphological Association of Korea
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    • v.17 no.1
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    • pp.1-14
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    • 2010
  • This paper deals with the classification and distribution of geomorphic surfaces and analysis on effects of geomorphic processes on the landforms in the inaccessable DMZ (Demilitarized Zone) to Wonsan Bay of East Sea coast of Chugaryeong Rift Valley, Central Korea. DEM (Digital Elevation Model) and Landsat images are used for the above anlaysis. The geomorphic surfaces are classified by TPI (Topographical Position Index) for the analysis of the convexity and concavity calculated using topographical elements such as elevation, steepness, and relief. In the Chugayreong Valley, 10 geomorphic surfaces are classified as steep valley, shallow valley, upland drainage, U-shaped valley, plain, open slope, upper slope, local ridge, midslope ridge, and high ridge. Zonal Statistics presents average characteristics of geomorphological processes of surfaces by the relationships between bedrock and relief, surface and relief, and between surface and NDVI. So, these analysis can help to understand geomorphological process such as dissection of lava plateau and watershed divide evolution.

EVALUATION OF GFDL GCM CLIMATE VARIABILITY USING EOFS OF ZONAL AVERAGE TEMPERATURE DATA

  • Yoo, Chul-sang
    • Water Engineering Research
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    • v.5 no.2
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    • pp.69-79
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    • 2004
  • In this study the GFDL GCM generated (controlled run) zonal average temperature data are evaluated by comparing their EOFs with those from observed data. Even though the correlation matrices of observed and simulated data are shown significantly different (Polyak and North, 1997b), the EOFs derived are found very similar with very high pattern correlations. This means almost all the information (second-order statistics) derived from the observed data can be reproduced by the EOFs derived from the GFDL GCM simulates. Also, the EOFs from GFDL GCM were found to have more flexible structures than those from the observed. Thus, we may conclude that the GFDL GCM can simulate the Earth's energy balance system reasonably. However, more in detail research should be focused on the effect from various forcings on climate variability, as, in some cases, the effect of external forcings could shadow the system characteristics and mislead the simulation results.

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Distributional Uniqueness of Deciduous Oaks(Quercus L.) in the Korean Peninsula (한반도 하록 참나무류의 분포 특이성)

  • Kim, Yun-Ha;Kim, Jong-Won
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.20 no.2
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    • pp.37-59
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    • 2017
  • The Korean peninsula belongs to the temperate forest biome dominated by many deciduous oaks. We quantitatively and qualitatively studied vertical and horizontal distributions and habitat characteristics on the major oak species such as Quercus mongolica, Q. serrata, Q. variabilis, Q. dentata, Q. aliena and Q. acutissima. A total of 5,278 samples were analyzed with a species coverage and 6 principal environmental variables extracted from public database of nationwide natural environment survey. Correlation analysis was accomplished by the CANOCO using Canonical Correspondence Analysis and the Pearson correlation coefficient using PASW Statistics. The hierarchical distribution tendency of six oaks was finalized using the Goodman-Kruskal lambda coefficient of non-metric multidimensional scaling by SYN-TAX 2000. The utmost factor on the distributional segregation of oak species was the elevation, i.e. temperature. Q. serrata and Q. mongolica show clearly a diametrical distribution patterns with zonal distribution. Q. variabilis was determined as a thermophilic and xerophilous species that is a component of not only natural pseudo-climax forest but also secondary forest. The highest frequency of the dominant forest was found Q. mongolica. Whereas, Q. serrata showed the highest frequency of individual tree but the relatively lower frequency of dominant forest, which is resulted from the original habitat loss. By the benefit of the traditional Soopjeong-E, Q. acutissima dominant forests were remained rather largely. Individuals of Q. dentata occurred horizontally nationwide, but its dominant forest was the poorest. Dominant forest of Q. aliena, which is a natural vegetation, was the most rare due to a limited potential habitat.

Application of the Cost-Distance Measures for Designating Zone Boundaries in DIF Zoning

  • Choi, Joon Young;Choei, Nae Young
    • Journal of Korean Society for Geospatial Information Science
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    • v.24 no.2
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    • pp.3-13
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    • 2016
  • The development impact fee (DIF) zoning is used to adequately provide the pre-planned urban infrastructures in those urban and regional sectors where significant urban sprawl has already taken place followed by the rapid population growth. The infrastructure installation fees are levied to those landowners whose properties belong to the DIF zone in which they enjoy the direct benefits that accrue from the installed infrastructures. While the law is deemed to be equitable in that the actual beneficiaries pay for their benefits, it is required to designate the zone boundaries accurately and consistently since they are the very dividers that differentiate the legitimate fee-payers and the free-riders. This study, especially, tries to test a seemingly advanced alternative, so-called the cost-weighted distance measure, as a potential candidate to replace the current air-distance measures to designate the zone boundaries. The statistics indicate that the coefficient of variation for major indices spread from 11.75 to 35.6 in the case of the latter method, it only ranges from 0.21 to 0.76 in the case of the former. The zonal outcomes also show much higher consistency in their shapes. It is hoped, in this context, that the study findings could possibly be adopted in the future research efforts expected soon to amend and improve the current DIF zoning law.

Climatology of Equatorial Plasma Bubbles in Ionospheric Connection Explorer/Far-UltraViolet (ICON/FUV) Limb Images

  • Park, Jaeheung;Mende, Stephen B.;Eastes, Richard W.;Frey, Harald U.
    • Journal of Astronomy and Space Sciences
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    • v.39 no.3
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    • pp.87-98
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    • 2022
  • The Far-UltraViolet (FUV) imager onboard the Ionospheric Connection Explorer (ICON) spacecraft provides two-dimensional limb images of oxygen airglow in the nightside low-latitude ionosphere that are used to determine the oxygen ion density. As yet, no FUV limb imager has been used for climatological analyses of Equatorial Plasma Bubbles (EPBs). To examine the potential of ICON/FUV for this purpose, we statistically investigate small-scale (~180 km) fluctuations of oxygen ion density in its limb images. The seasonal-longitudinal variations of the fluctuation level reasonably conform to the EPB statistics in existing literature. To further validate the ICON/FUV data quality, we also inspect climatology of the ambient (unfiltered) nightside oxygen ion density. The ambient density exhibits (1) the well-known zonal wavenumber-4 signatures in the Equatorial Ionization Anomaly (EIA) and (2) off-equatorial enhancement above the Caribbean, both of which agree with previous studies. Merits of ICON/FUV observations over other conventional data sets are discussed in this paper. Furthermore, we suggest possible directions of future work, e.g., synergy between ICON/FUV and the Global-scale Observations of the Limb and Disk (GOLD) mission.

On the Annual Change of Surface Wind at Seocheon, Korea (서천지방의 지상풍 연변화에 관하여)

  • 문승의;김백조
    • Journal of Environmental Science International
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    • v.7 no.3
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    • pp.375-382
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    • 1998
  • The characteristics of the basic statistics and steadiness of wind and the monthly normality test of surface wind distribution are investigated by using the observed wind data compiled from 10m meteorological observation tower at Seocheon district, where is located In the western coastal region of Korea. during the period from Feb. 7, 1996 to Feb. 7 1997 The northerly is appeared to be even in August and Sepember due to the influences of loccal circulation such as land and sea breeze. The correlation coefacients between two wind components are seemed to be positive during the in the period of from June to September and negative from October to April, respectively The constancy of wand Is high In shifts to lower values Increasing sampling time. It is found from monthly normality test based on the skewness and the excess of kurtosis coefficients that the distribution of zonal wind component is normal In spring and meridional one Is normal in late summer and early autumn.

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Unsupervised Change Detection Based on Sequential Spectral Change Vector Analysis for Updating Land Cover Map (토지피복지도 갱신을 위한 S2CVA 기반 무감독 변화탐지)

  • Park, Nyunghee;Kim, Donghak;Ahn, Jaeyoon;Choi, Jaewan;Park, Wanyong;Park, Hyunchun
    • Korean Journal of Remote Sensing
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    • v.33 no.6_2
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    • pp.1075-1087
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    • 2017
  • In this study, we tried to utilize results of the change detection analysis for satellite images as the basis for updating the land cover map. The Sequential Spectral Change Vector Analysis ($S^2CVA$) was applied to multi-temporal multispectral satellite imagery in order to extract changed areas, efficiently. Especially, we minimized the false alarm rate of unsupervised change detection due to the seasonal variation using the direction information in $S^2CVA$. The binary image, which is the result of unsupervised change detection, was integrated with the existing land cover map using the zonal statistics. And then, object-based analysis was performed to determine the changed area. In the experiment using PlanetScope data and the land cover map of the Ministry of Environment, the change areas within the existing land cover map could be detected efficiently.

Mapping of Inundation Vulnerability Using Geomorphic Characteristics of Flood-damaged Farmlands - A Case Study of Jinju City - (침수피해 정보를 이용한 농경지의 지형학적 침수취약지도 작성 - 진주시를 사례로 -)

  • Kim, Soo-Jin;Suh, Kyo;Kim, Sang-Min;Lee, Kyung-Do;Jang, Min-Won
    • Journal of Korean Society of Rural Planning
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    • v.19 no.3
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    • pp.51-59
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    • 2013
  • The objective of this study was to make a map of farmland vulnerability to flood inundation based on morphologic characteristics from the flood-damaged areas. Vulnerability mapping based on the records of flood damages has been conducted in four successive steps; data preparation and preprocessing, identification of morphologic criteria, calculation of inundation vulnerability index using a fuzzy membership function, and evaluation of inundation vulnerability. At the first step, three primary digital data at 30-m resolution were produced as follows: digital elevation model, hill slopes map, and distance from water body map. Secondly zonal statistics were conducted from such three raster data to identify geomorphic features in common. Thirdly inundation vulnerability index was defined as the value of 0 to 1 by applying a fuzzy linear membership function to the accumulation of raster data reclassified as 1 for cells satisfying each geomorphic condition. Lastly inundation vulnerability was suggested to be divided into five stages by 0.25 interval i.e. extremely vulnerable, highly vulnerable, normally vulnerable, less vulnerable, and resilient. For a case study of the Jinju, farmlands of $138.6km^2$, about 18% of the whole area of Jinju, were classified as vulnerable to inundation, and about $6.6km^2$ of farmlands with elevation of below 19 m at sea water level, slope of below 3.5 degrees, and within 115 m distance from water body were exposed to extremely vulnerable to inundation. Comparatively Geumsan-myeon and Sabong-myeon were revealed as the most vulnerable to farmland inundation in the Jinju.

Preparation of Landslide Hazard Map Using the Analysis of Historical Data and GIS Method (GIS 기법 및 발생자료 분석을 이용한 산사태 위험지도 작성)

  • Yun, Hong-Sik;Lee, Dong-Ha;Suh, Yong-Cheol
    • Journal of the Korean Association of Geographic Information Studies
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    • v.12 no.4
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    • pp.59-73
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    • 2009
  • In this study, we performed a GIS-based landslide hazard analysis by employing historical landslide data in Korea, coupling with geomorphological, geological, climatic and rainfall data. Based on 596 landslide data from 2001 to 2003, the correlations between landslide occurrence and various factors (elevation, slope angle, slope aspect, soil type and rainfall) that affect the occurrence were estimated by the statistical analysis, zonal statistics. The weights and hazard indices of 6 raster layers were derived from the estimated correlations in order to generate a landslide hazard map by applying raster calculation technique. As a result of this study, GIS technique can be used effectively to incorporate the landslide hazard contributions from various data sets simultaneously.

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A GIS-based Environmental Sensitivity Assessment of Geopark - Slope Disaster in Cheongsong UNESCO Global Geopark - (GIS를 활용한 지오파크 환경 민감성 평가 - 청송 세계지질공원의 사면재해 민감성을 중심으로 -)

  • Kim, Hyejin;Sung, Hyo Hyun;Kim, Jisoo;Ahn, Sejin
    • Journal of The Geomorphological Association of Korea
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    • v.27 no.2
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    • pp.81-97
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    • 2020
  • Geopark refers to a single boundary area consisting of a collection of geosites and geotrails, which includes ecological, historical and cultural elements based on geological and geomorphological resources. To ensure the continued development and conservation of existing listed geoparks, it is necessary to carry out an environmental sensitivity analysis of the geopark components by utilizing spatial information from various scales. The objectives of this study are to analyze the environmental sensitivity in Cheongsong UNESCO global geopark in relation with slope disaster using GIS and to understand its spatial distribution in connection with geosites and geotrails. Two types of spatial database were constructed; geosites and geotrails in Cheongsong UNESCO global geopark and spatial data to perform environmental sensitivity. Potential soil loss and slope stability were analyzed to derive environmental sensitivity related to slope hazard. The results showed relatively high environmental sensitivity along the drainage network of Cheongsong UNESCO global geopark. Zonal statistics analysis was conducted for further detailed distribution of environmental sensitivity based on buffer zones of geosites and geotrails. Majority of geological sites, geological trails, Jeolgol gorge~Jusan Pond section in hiking trails, and Dalgi Mineral Spring Site~Artistic Genius Republic of Korea(Jangnankki gonghwaguk) section in road areas show relatively high slope hazard sensitivity within buffer zones.