• Korean Journal of Remote Sensing
• /
• v.16 no.3
• /
• pp.221-233
• /
• 2000

An intertidal topography is continuously changed due to morphodynamics processes. Detection and measurement of topographic change for a tidal flat is important to make an integrated coastal area management plan as well as to carry out sedimentologic study. The objective of this study is to generate intertidal DEM using leveling data and waterlines extracted from optical and microwave remotely sensed data in a relatively short period. Waterline is defined as the border line between exposed tidal flat and water body. The contour of the terrain height in tidal flat is equivalent to the waterline. One can utilize satellite images to generate intertidal DEM over large areas. Extraction of the waterline in a SAR image is a difficult task to perform partly because of the presence of speckle and partly because of similarity between the signal returned from the sea surface and that from the exposed tidal flat surface or land. Waterlines in SAR intensity and coherence map can effectively be extracted with MSP-RoA edge detector. From multiple images obtained over a range of tide elevation, it is possible to build up a set of heighted waterline within intertidal zone, and then a gridded DEM can be interpolated. We have tested the proposed method over the Gomso Bay, and succeeded in generating intertidal DEM with relatively high accuracy.

• Spatial Information Research
• /
• v.3 no.2
• /
• pp.179-189
• /
• 1995

To make vector data from a map which has no negative plates by using vectoring tool, it is necessary that we can extract objects to be vectorized from a scanned map. In this paper, we studied on extracting vectoring objects from scanned color maps. To do this, we classified vectoring objects into three types : line type, filled - area type and character/symbol type. To make the extraction method effective, we analyzed characteristics of vectoring objects and color distribution in scanned color maps. Then, we applied these characteristics to designing process of the extraction method. To extract the line type object, our line tracing method was designed by using the masks which considered connectivity and geometrical characteristics of lines. By using the local thresholding method and the similarity function for comparing the color distribution between two NxN blocks, we extracted character/symbol and the filled-area objects effectively. The method proposed in this paper can be used for constructing the small scale GIS application economically using existing color maps.

• Proceedings of the KSRS Conference
• /
• 2006.03a
• /
• pp.79-82
• /
• 2006

조간대 지형의 발달과 변화에 대한 이해는 물순환 모델, 양식장 관리, 전자해도의 갱신, 연안개발 계획수립, 항로의 효율적 관리, 선박 안전항해, 상륙 작전 등에 있어서 매우 중요하다. 기존의 조간대 DEM 을 만드는 방법 중 위성영상을 이용한 waterline 방법과 선박을 이용한 음향측심(echo sounding) 방법이 있다. 이 연구의 목적은 위성 원격탐사 자료와 음향측심기 자료를 함께 사용하여 각각의 방법의 단점을 보완함으로서 조간대 DEM 의 정밀도를 향상시키는 것이다. 천수만 황도 조간대에 대해 음향측심에 의해 얻어진 자료를 관측소 조위와 단위를 일치시킨 후 광학위성으로부터 추출된 waterline 자료와 합성하여 DEM 을 제작하였다. 합성된 DEM 과 기존의 waterline 방법과 음향측심법으로 제작된 DEM 과 비교해 본 결과, 합성된 DEM 은 음향측심 자료에 의해 정밀도가 많이 향상되었으며 waterline 방법에 의해 지역적 특성이 잘 표현되었다. 따라서 개발된 방법은 음향측심 방법에 의해 만들어졌던 기존 해도의 정밀도를 업그레이드 하는데 활용될 수 있을 것으로 기대된다.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.4 no.4
• /
• pp.39-50
• /
• 2001

There has been considerable controversy over the changes in the size of the beaches in the Pusan area; any loss of beach area will have an immense effect on the tourism industry, which is an important source of income for the local economy. The best beaches in Korea are in the Pusan area and were visited by more than 8 million persons in 2000. It is expected that the number of visitors, drawn to the scenic vistas and convenient facilities of this area, will increase annually. Any loss in the size of these swimming beaches will have an important negative effect on tourism income. Therefore, the local governments have gone to great lengths to preserve these beaches, transporting tens of thousands of tons of sand to the beaches before they open each year at a cost of billions of won annually. In this study, we analyzed aerial photographs and tide data for the past 50 years using digital aerial photo analysis and GIS techniques for each 3-year interval. We abstracted beach DEM (digital elevation model) and ortho aerial photographs, and conducted a space analysis. As a result, we were able to identify changes in the area and width of sections of Haeundae Beach.

• Journal of the Korean earth science society
• /
• v.24 no.5
• /
• pp.477-490
• /
• 2003

Bottom sediments from Youngil Bay, East Coast of Korea, were analyzed for grain composition as well as elemental compositions and total organic carbon (TOC) content in order to investigate the spatial variability and content of metal elements. Grain size distribution of the sediments seems to be controlled by anticlockwise current pattern with bottom topography of the study area. Spatial variability of TOC and all elemental contents reflects those of grain size, but an exception was found in the harbor area (Old-Port): their contents are high in the central part of the bay with the muddy sediment and decrease toward the sand-dominated coastal zone. However, contents of Ca, Sr, K are high in the sand-dominated coastal zone and contents of some heavy metals (Cd, Cu, Zn) are high in the Old-Port area and the mouth of Hyeongsan River. The correlation matrix and R-mode factor analyses reveal that four important factors controlling the distribution of metals in the bay are sediment grain size (or quartz dilution effect), the formation of sulfide minerals associated with decomposition of organic matters under anoxic geochemical environment, calcium carbonate (mainly shell fragments) and coarse-grained feldspar mineral. According to the metal content of labile fraction an CER (concentration enrichment ratio) value, high accumulation of some heavy metals in the harbor area seems to result not formed by early diagenetic processes under anoxic environment.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2010.10a
• /
• pp.7-9
• /
• 2010

전자해도에는 해안선, 등심선, 수심, 항로표지, 위험물, 항로 등 선박의 항해와 관련된 모든 해도정보를 포함하고 있으며, 각 정보는 속성정보와 공간정보를 가지고 데이터 레코드 단위로 저장된다. 수심 정보의 경우 점 형태의 공간정보로서 전자해도 격자 구역에 포함되는 수백에서 수천 개의 수심 위경도 좌표와 수심정보를 포함하고 있다. 수심 정보는 전자해도 중첩의 주된 원인이 되어 수심정보의 최적표현 기법 개발이 요구되었다. 본 연구에서는 전자해도 수심정보의 표현 기준을 수립하고, 기준에 따라 수심정보의 최적표현 방법을 제안하였다. 세부 내용으로 전자해도 수심정보 표현기준을 작성하고 전자해도에서 수심정보를 추출한 다음 기준에 따라 수심정보를 분류 하였다. 또한 분류한 수심정보를 전자해도에 저장하고 그 결과를 확인 하였다.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2006.04a
• /
• pp.451-456
• /
• 2006

Shoreline changes its shape and attribution dynamically by natural, unnatural acts and is the most important information for defining a countries territory. These shorelines can apply to frame work of MGIS, and they are getting important because we can implement the data for creating monitoring systems around coastal areas. This study proposed an algorithm for extracting shorelines automatically using a new developed Lidar data which is applied in ocean and coastal areas. Its result was compared to shorelines which were derived from ground survey. It showed stable shorelines in both natural, and artificial coast areas. It showed the possibility of extracting shorelines with LiDAR data and proved the method was more efficient and economical compared to recent studies and methods.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2006.04a
• /
• pp.457-462
• /
• 2006

Coastline has been considered as fundamental geographic information of a nation. Recently, the coastlines of higher resolution and accuracy with less update period ever than before are increasingly required. This requirement cannot be easily satisfied with the most traditional methods based on field survey such as leveling or GPS measurements. The newly developed airborne LIDAR system can be used as a promising alternative since it rapidly acquire numerous three-dimensional points densely sampled from the terrain around the coastline. Hence, in this study we developed a nearly automatic method to extract the coastline from LIDAR data and applied it to real data to verify its performance. From the comparison of the extracted coastlines with those from a digital map, we conclude that the proposed method can provide more accurate and precise lines.

• Proceedings of the KSRS Conference
• /
• 2001.03a
• /
• pp.116-121
• /
• 2001

경기만 지역은 세계최대 규모의 갯벌이 조성되어 해양생태계에서 중요한 역할을 수행하는 자연의 보고이나, 강한 조류운동, 한강 유역으로부터의 토사이동, 그리고 계속되는 연안 개발등 지속적인 영향을 받고 있다. 본 연구에서는 이러한 경기만 지역의 지리적·환경적 요인에 기인한 갯벌지역의 지난 30년 동안 공간적 변화를 분석하고자 한다. 해안선·조간대 지형의 변화 특성은 1972년부터 1999년까지 약 5년 간격으로 촬영된 Landsat MSS 와 TM 영상들을 이용하여 분석하였다. MSS와 TM의 공통적인 파장대이며, 물과 조간대의 경계가 뚜렷한 근적외선 파장대를 이용하여 간조시 갯벌의 경계선을 추출하였다. 각 시기의 수면, 갯벌, 육지를 나타내는 수치지도가 제작된 후, 이들을 중첩함으로써 시기별 변화유형을 구분하였고, 변화유형을 다시 원인에 따라 인공적인 요인과 자연적인 요인으로 나누었다. 의미있는 변화 유형은 크게 8가지로 나타났으며, 변화유형과 변화요인을 연계하여 경기만 지역의 변화특성을 도출하였다.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.9 no.4
• /
• pp.224-232
• /
• 2006

This study investigates to detect Sea Surface Temperature (SST) and land cover change after tide embankment construction using Landsat Thematic Mapper (TM) Thermal Infrared (TIR) band data at Shihwa Lake and surrounding area. SST measurement is important for studies of both the structure of the ocean and as the thermal boundary between the ocean and the atmosphere. Since 1970s, the derivation of SST by satellite remote sensing (RS) has been applied to earth surface using Advanced Very High Resolution Radiometer (AVHRR) and Landsat TM. However, AVHRR has restriction in deriving SST in the area whose shoreline is complicated like western coast in South Korea because of coarse spatial resolution. The TIR band of TM images can be used to detect SST change whose shoreline is complicated and narrow like the study site. Thus, multi-temporal TM images were used for SST change detection in this study.