• Title/Summary/Keyword: high resolution DEM

Search Result 180, Processing Time 0.018 seconds

Development of HDF Browser for the Utilization of EOC Imagery

  • Seo, Hee-Kyung;Ahn, Seok-Beom;Park, Eun-Chul;Hahn, Kwang-Soo;Choi, Joon-Soo;Kim, Choen
    • Korean Journal of Remote Sensing
    • /
    • v.18 no.1
    • /
    • pp.61-69
    • /
    • 2002
  • The purpose of Electro-Optical Camera (EOC), the primary payload of KOMPSAT-1, is to collect high resolution visible imagery of the Earth including Korean Peninsula. EOC images will be distributed to the public or many user groups including government, public corporations, academic or research institutes. KARI will offer the online service to the users through internet. Some application, e.g., generation of Digital Elevation Model (DEM), needs a secondary data such as satellite ephemeris data, attitude data to process the EOC imagery. EOC imagery with these ancillary information will be distributed in a file of Hierarchical Data Format (HDF) file formal. HDF is a physical file format that allows storage of many different types of scientific data including images, multidimensional data arrays, record oriented data, and point data. By the lack of public domain softwares supporting HDF file format, many public users may not access EOC data without difficulty. The purpose of this research is to develop a browsing system of EOC data for the general users not only for scientists who are the main users of HDF. The system is PC-based and huts user-friendly interface.

Utilization Plan Research of High Resolution Images for Efficient River Zone Management (효율적 하천구역관리를 위한 고해상 영상의 활용 방안 연구)

  • Park, Hyeon-Cheol;Kim, Hyoung-Sub;Jo, Yun-Won;Jo, Myung-Hee
    • Korean Journal of Remote Sensing
    • /
    • v.24 no.2
    • /
    • pp.205-211
    • /
    • 2008
  • The river management in Korea had been focused on line based 2D spatial data for the developing river management application system. In this study, the polygon based 3D spatial data such as aerial photos and satellite images were selected and used through comparing their resolution levels for the river environment management. In addition, 1m detailed DEM (Digital Elevation Model) was constructed to implement the real topography information around river so that the damage area scale could be extracted for flood disaster. Also, the social environment thematic maps such as a cadastral map or land cover map could be used to verify the real damage area scale by overlay analysis on aerial photos or satellite images. The construction of these spatial data makes possible to present the real surface information and extract quantitative analysis to support the scientific decision making for establishing the river management policy. For the further study, the lidar surveying data will be considered as the very useful data by offering the real height information of riverbed as the depth of river so that flood simulation can give more reality.

Comparisons of 1-Hour-Averaged Surface Temperatures from High-Resolution Reanalysis Data and Surface Observations (고해상도 재분석자료와 관측소 1시간 평균 지상 온도 비교)

  • Song, Hyunggyu;Youn, Daeok
    • Journal of the Korean earth science society
    • /
    • v.41 no.2
    • /
    • pp.95-110
    • /
    • 2020
  • Comparisons between two different surface temperatures from high-resolution ECMWF ReAnalysis 5 (ERA5) and Automated Synoptic Observing System (ASOS) observations were performed to investigate the reliability of the new reanalysis data over South Korea. As ERA5 has been recently produced and provided to the public, it will be highly used in various research fields. The analysis period in this study is limited to 1999-2018 because regularly recorded hourly data have been provided for 61 ASOS stations since 1999. Topographic characteristics of the 61 ASOS locations are classified as inland, coastal, and mountain based on Digital Elevation Model (DEM) data. The spatial distributions of whole period time-averaged temperatures for ASOS and ERA5 were similar without significant differences in their values. Scatter plots between ASOS and ERA5 for three different periods of yearlong, summer, and winter confirmed the characteristics of seasonal variability, also shown in the time-series of monthly error probability density functions (PDFs). Statistical indices NMB, RMSE, R, and IOA were adopted to quantify the temperature differences, which showed no significant differences in all indices, as R and IOA were all close to 0.99. In particular, the daily mean temperature differences based on 1-hour-averaged temperature had a smaller error than the classical daily mean temperature differences, showing a higher correlation between the two data. To check if the complex topography inside one ERA5 grid cell is related to the temperature differences, the kurtosis and skewness values of 90-m DEM PDFs in a ERA5 grid cell were compared to the one-year period amplitude among those of the power spectrum in the time-series of monthly temperature error PDFs at each station, showing positive correlations. The results account for the topographic effect as one of the largest possible drivers of the difference between ASOS and ERA5.

An Automated OpenGIS-based Tool Development for Flood Inundation Mapping and its Applications in Jeju Hancheon (OpenGIS 기반 홍수범람지도 작성 자동화 툴 개발 및 제주 한천 적용 연구)

  • Kim, Kyungdong;Kim, Taeeun;Kim, Dongsu;Yang, Sungkee
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.39 no.6
    • /
    • pp.691-702
    • /
    • 2019
  • Flood inundation map has various important roles in terms of municipal planning, timely dam operation, economic levee design, and building flood forecasting systems. Considering that the riparian areas adjacent to national rivers with high potential flood vulnerability conventionally imposed special cares to justify applications of recently available two- or three-dimensional flood inundation numerical models on top of digital elevation models of dense spatial resolution such as LiDAR irrespective of their high costs. On the contrary, local streams usually could not have benefits from recent technological advances, instead they inevitably have relied upon time-consuming manual drawings or have accepted DEMs with poor resolutions or inaccurate 1D numerical models for producing inundation maps due mainly to limited budgets and suitable techniques. In order to efficiently and cost-effectively provide a series of flood inundation maps dedicatedly for the local streams, this study proposed an OpenGIS-based flood mapping tool named Open Flood Mapper (OFM). The spatial accuracy of flood inundation map derived from the OFM was validated throughout comparison with an inundation trace map acquired after typhoon Nari in Hancheon basin located in Jeju Island. Also, a series of inundation maps from the OFM were comprehensively investigated to track the burst of flood in the extreme flood events.

Analysis of Debris Flow Deposition based on Topographic Characteristics of Debris Flow Path (유하부 지형 특성에 따른 토석류 퇴적 분석)

  • Kim, Gihong;Youn, Junhee
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
    • /
    • v.31 no.6_1
    • /
    • pp.471-481
    • /
    • 2013
  • Recently, the frequency of debris flow disaster has increased, which is one of the natural disasters during extremely heavy rainfall condition. This paper described the analysis method about deposition characteristics of debris flow using topographic characteristics of debris flow path. First, we observed topographic changes by differencing high- resolution LiDAR DEMs acquired before and after the occurrence of debris flow event. We assumed that deposition on outside of debris flow path was generated by movements due to the inertia of debris flows. Then, we analyzed three topographic characteristics of debris flow path: slope in flow direction, transition angle of flow path, and the net efficiency(L/H) of debris flows defined by the ratio of transport length(L) and elevation difference(H). We applied this method to Umyeon Mountain debris flow event in July 2011. The results showed that deposition on outside of debris flow path due to the inertia of debris flows was significantly related to the transition angle of debris flow path. Also, we figured out that there were more frequent such depositions in locations where the ratio of 'transition angle / (L/H)' is over 8.

The Intertidal Area in Lake Sihwa After Operation of the Tidal Power Plant (조력발전소 가동 후 시화호 내 조간대의 면적 변화)

  • Kim, Minkyu;Koo, Bon Joo
    • Journal of the Korean Society for Marine Environment & Energy
    • /
    • v.18 no.4
    • /
    • pp.310-316
    • /
    • 2015
  • The intertidal area in Lake Sihwa formed after operation of Sihwa-Lake tidal power plant and the change of the area in Lake Sihwa by period were analyzed. For computation of the intertidal area, remote sensing techniques were applied and high resolution Digital Elevation Model (DEM) was generated with root mean square (rms) error 14.4 cm. The intertidal area was $165.1km^2$ in 1910s, $115.2km^2$ in 1991 before completion of Sihwa dyke, $5.6km^2$ in 2010 during the period on operation of sluice gate, and $20.3km^2$ in 2013 after operation of Sihwa tidal power plant. Intertidal in Lake Sihwa was nearly dissipated after completion of Sihwa dyke, but significantly increased with operation of Sihwa tidal power plant from April 2012 as developing a regular tide environment and increasing of sea water flux. The re-formation of tidal flat of Sihwa Lake is an uncommon case. This study that precisely analyzed on the area of artificially formed Sihwa tidal flat would be applicable for management and making conservation plan.

Classification of Sedimentary Facies Using IKONOS Image in Hwangdo Tidal Flat, Cheonsu Bay (IKONOS 영상을 이용한 천수만 황도 갯벌 표층 퇴적상 분류)

  • Ryu, Joo-Hyung;Woo, Han Jun;Park, Chan-Hong;Yoo, Hong-Rhyong
    • Journal of Wetlands Research
    • /
    • v.7 no.2
    • /
    • pp.121-132
    • /
    • 2005
  • To classify the surface sedimentary facies using IKONOS image collected over Hwangdo tidal flat in Cheonsu Bay, the optical reflectance was compared for characterizing various sedimentary environments such as grain size, tidal channel pattern and area ratio of surface remnant water. The intertidal DEM (Digital Elevation Model) was generated by echo-sounder for analyzing the relationship between IKONOS image and sedimentary environments including topography. The boundary of the optical reflectance between mud-mixed facies and sand facies was distinct, and discrimination of the associated sandbar feature was also possible. The mud-mixed facies coupled with intricate tidal channels is confined to the relatively hi호 topography of Hwangdo tidal flat. The boundary between mud and mixed flat was indistinct in IKONOS optical reflectance but it would have a difference in the area ratio of surface remnant water. The dark area in the image represented the well developed sand facies having a lot of surface remnant water due to the relatively low surface topography. The overall accuracy of characterizing the surface sediment facies by maximum likelihood classification method was 86.2 %. These results demonstrate that high spatial resolution satellite imagery such as IKONOS coupled with knowledge of grain size, surface remnant water and tidal channel network can be effectively used to characterize the surface sedimentary facies (mud, mixed and sand) network of the tidal flat environments.

  • PDF

Generation of Large-scale Map of Surface Sedimentary Facies in Intertidal Zone by Using UAV Data and Object-based Image Analysis (OBIA) (UAV 자료와 객체기반영상분석을 활용한 대축척 갯벌 표층 퇴적상 분류도 작성)

  • Kim, Kye-Lim;Ryu, Joo-Hyung
    • Korean Journal of Remote Sensing
    • /
    • v.36 no.2_2
    • /
    • pp.277-292
    • /
    • 2020
  • The purpose of this study is to propose the possibility of precise surface sedimentary facies classification and a more accurate classification method by generating the large-scale map of surface sedimentary facies based on UAV data and object-based image analysis (OBIA) for Hwang-do tidal flat in Cheonsu bay. The very high resolution UAV data extracted factors that affect the classification of surface sedimentary facies, such as RGB ortho imagery, Digital elevation model (DEM), and tidal channel density, and analyzed the principal components of surface sedimentary facies through statistical analysis methods. Based on principal components, input data to be used for classification of surface sedimentary facies were divided into three cases such as (1) visible band spectrum, (2) topographical elevation and tidal channel density, (3) visible band spectrum and topographical elevation, tidal channel density. The object-based image analysis classification method was applied to map the classification of surface sedimentary facies according to conditions of input data. The surface sedimentary facies could be classified into a total of six sedimentary facies following the folk classification criteria. In addition, the use of visible band spectrum, topographical elevation, and tidal channel density enabled the most effective classification of surface sedimentary facies with a total accuracy of 63.04% and the Kappa coefficient of 0.54.

Analyzing Characteristics of Forest Damage within the Geum-buk Mountain Range (금북정맥의 산림훼손 특성 분석)

  • Jang, Gab-Sue;Jeon, Seong-Woo;Kim, Sang-Soo
    • Journal of the Korean Institute of Landscape Architecture
    • /
    • v.36 no.5
    • /
    • pp.55-63
    • /
    • 2008
  • The characteristics of forest damage in the Geum-buk Mountains were analyzed by using satellite images and a field survey for landscape conservation purposes. A survey scope was fixed using DEM, and areas of damage in the mountain range were analyzed via ArcMap v. 9.2 using SPOT 5 images, a high resolution satellite image. All damaged areas were reviewed and corrected in a field survey. As a result, 75 roads were found to completely fragment forest patches. Of those roads, 26 have the width under 3m, which means that the fragmentation of the forest by these roads may have a minor effect on forest habitat and its ecosystems, while other roads such as two-lane roads may have broader detrimental influences on the ecosystem. Two thousand eighty-three sections of accounted for a total area of about 5,760.7ha. Orchard areas including chestnut tree plantations were ranked as the largest in the damaged area within the Geum-buk Mountains, followed by public facility areas and grassland areas. This means that man-made land usage has progressed in the area regardless of slope and elevation.

The Characteristics of Submarine Groundwater Discharge in the Coastal Area of Nakdong River Basin (낙동강 유역의 연안 해저지하수 유출특성에 관한 연구)

  • Kim, Daesun;Jung, Hahn Chul
    • Korean Journal of Remote Sensing
    • /
    • v.37 no.6_1
    • /
    • pp.1589-1597
    • /
    • 2021
  • Submarine groundwater discharge (SGD) in coastal areas is gaining importance as a major transport route that bring nutrients and trace metals into the ocean. This paper describes the analysis of the seasonal changes and spatiotemporal characteristicsthrough the modeling monthly SGD for 35 years from 1986 to 2020 for the Nakdong river basin. In this study, we extracted 210 watersheds and SGD estimation points using the SRTM (Shuttle Radar Topography Mission) DEM (Digital Elevation Model). The average annual SGD of the Nakdong River basin was estimated to be 466.7 m2/yr from the FLDAS (Famine Early Warning Systems Network Land Data Assimilation System) recharge data of 10 km which is the highest resolution global model applicable to Korea. There was no significant time-series variation of SGD in the Nakdong river basin, but the concentrated period of SGD was expanded from summer to autumn. In addition, it was confirmed that there is a large amount of SGD regardless of the season in coastal area nearby large rivers, and the trend has slightly increased since the 1980s. The characteristics are considered to be related to the change in the major precipitation period in the study area, and spatially it is due to the high baseflow-groundwater in the vicinity of large rivers. This study is a precedentstudy that presents a modeling technique to explore the characteristics of SGD in Korea, and is expected to be useful as foundational information for coastal management and evaluating the impact of SGD to the ocean.