• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.5
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• pp.485-491
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• 2010

Acquisition of information on failure slope, which may cause apprehension of second hand damage, requires acquisition of fast and accurate topographical data and efficient expression in indirect surveying method without accessing as needed. Therefore, in this study, the images on the intended area were photographed through hovering in the air by approaching collapsed road cut slope with the use of unmanned helicopter photography system. As a result of comparing the points observed by no prism total station and the 10 coordinate points analyzed through image analysis, the averages of absolute values were shown to be 0.056m in X axis direction, 0.082m in Y axis direction and 0.066m Z axis direction. In addition, the RMSE of the error for 10 points of test points were 0.015636m in X axis direction, 0.021319m in Y axis direction and 0.018734m in Z axis direction. Therefore, this method can determine the range of slope and longitudinal and cross sections of each slope in dangerous area that cannot be approached in relational image matching method for the terrains of such collapsed cut slope.

• Journal of The Geomorphological Association of Korea
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• v.21 no.4
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• pp.85-96
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• 2014

A waterfall is a channel unit with steep bedrock. No strict criteria for height, water volume, gradient to define waterfalls exist in Korea. The goal of our study is to classify waterfalls based on morphological forms which are the outcomes of developmental processes. The genesis of waterfall depends upon erosional properties of waterfall. The height, gradient, bedrock strength and stream power of waterfalls are regarded as the main factors, by which waterfalls can be classified. We find out that the most important factor for the development of waterfalls is joint system. Development of joint system varies depending on bedrocks. Flow directions and erosional types are decided by the density and direction of joint system in the bedrock, which also decide the height and gradient of stream bed. Joint type decides the gradients of the bed, gradient and height of waterfalls, therefore, decides morphological forms.

• Journal of The Geomorphological Association of Korea
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• v.19 no.2
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• pp.161-172
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• 2012

The Taeanhaean National Park is located on the middle of the west coast of Korean peninsula. Due to the relatively high wave energy, large tidal range which is about 7m, and extremely complex coastal line, various coastal land-forms such as mud-flats, sand beaches, sand dunes, sea cliffs etc. are well distributed in this area, and thus various coastal ecosystems are well preserved. However, because of reckless sand diggings and construction of artificial structures in the coastal zone, the natural flowing and exchange of coastal deposits were disturbed and the erosion in the beach and the dune has been seriously accelerated. To understand of the causes of these problems, we tried three times periodical measuring with VRS/RTK GPS instrument at the Hakampo and Anmyeon beach. According to seasonal changes of the coast-line, beach area and cross-section of study sites, generally erosion process was dominated in the summer and deposition process was followed after summer.

• Journal of The Geomorphological Association of Korea
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• v.20 no.4
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• pp.71-83
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• 2013

In this study, the ecological presevation zone on uninhabited islands was established based on the setting of geomorphological landscape. The 14 uninhabited islands, which are scattered around the Goseong-gun and Tongyeong-si region have been surveyed on field. As a result of study, uninhabited island of Goseong-gun and Tongyeong-si was classified the absolute preservation areas(I), preservation areas(II), quasi-preservation areas(III), and a available areas(IV). These results evaluated 5 islands of Anjang Island(Maan-do), Bam Island, Saetgaekkeut, Dae Island(Juk-do) and Ttandok Island to be absolute preservation areas(I), the 8 islands of Mana Island, Yuk Island, Nabi Island, Sochi Island, Yongdu-do, Daeho-do, Jam-do, and Hwa-do to be preservation areas(II), the 1 island of Goeam Island to be quasipreservation areas(III). Those islands selected as absolute preservation areas and preservation areas have especially outstanding geomorphological landscape resources, and are expected to be able for use as natural study fields or as outdoor laboratories.

• Journal of The Geomorphological Association of Korea
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• v.19 no.4
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• pp.109-122
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• 2012

Topographic changes in the foredune in Sohwang-ri, Boryeong, Chungnam Province was analyzed over the last two years. Seven cross-sections and one permanent plot ($20m{\times}50m$) were periodically studied based on erosion and deposition measurement, in addition to vegetation monitoring and measurement of wind using an automatic weather station. The sand dunes usually grew from late winter to spring and the growth occurred in a period of strong northwesterly winds. From March to April, heavy sedimentation was observed on the front section of the foredune and sand piled up to ca. 30cm to the ca. 25m landward from the high tide line. It is likely that increased wind force and growth of vegetation played a major role in transportation and sedimentation of sand. Meanwhile, the lower part of the sand dunes was eroded when typhoon and spring tide caused a rise in sea level. The transition zone of beach and dune was usually affected by sea water but some frontal slopes were entirely influenced, resulting in dune scarps. The eroded scarps were naturally restored to their original state as time passed.

• Journal of Korean Elementary Science Education
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• v.40 no.3
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• pp.390-406
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• 2021

This study investigated how elementary students with different spatial ability constructed spatial thinking process about on volcanoes and earthquakes with GeoMapApp-based materials. Students' spatial thinking process was analyzed in terms of spatial concept recognized, tools of spatial representation, and their spatial reasoning to construct topographic structure. The student group with high-scored spatial ability showed the spatial reasoning based on internal representation of building mental images through sectional division of horizontal distance, directly connected with spatial concept, or distorting spatial concept. The student group with low-scored spatial ability built the spatial reasoning directly connected with spatial concept instead of transforming into internal representation, and partially recognized spatial concept on either distance or depth. Based on the results, we argued identifying spatial concepts such as distance, height, or depth from the GeoMapApp data would be funda- mental for the better spatial thinking.

• Economic and Environmental Geology
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• v.56 no.5
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• pp.589-601
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• 2023

We compare high-resolution seabed bathymetry data and seafloor backscattering data acquired, using multi-beam, between 2018 and 2021 to understand topographic changes in the coastal area of Dokdo. The study area, conducted within a 500 m × 500 m in the southern coast between the islands where Dongdo Port is located, has been greatly affected by human activities, waves and ocean currents. The depth variations exhibit between 5 - 70 m. Irregular underwater rocks are distributed in areas with a depth of 20 m or less and 30 - 40 m. As a whole, water depth ranges similar in the east-west direction and become flatter and deeper. The bathymetry contour in 2020 tends to move south as a whole compared to 2018 and 2019. The south moving of the contours in the survey area indicates that the water depth is shallower than before. Since the area where the change in the depth occurred is mainly formed of sedimentary layers, the change in the coast of Dokdo were mainly caused by the inflow of sediments, due to the influence of wind and waves caused by these typhoons (Maysak and Haishen) in 2020. In the Talus area, which developed on the shallow coast between Dongdo and Seodo, the bathymetry changed in 2020 due to erosion or sedimentation, compared to the bathymetry in 2019 and 2018. It is inferred that the changes in the seabed environment occur as the coastal area is directly affected by the typhoons. Due to the influence of the typhoons with strong southerly winds, there was a large amount of sediment inflow, and the overall tendency of the changes was to be deposited. The contours in 2021 appears to have shifted mainly northward, compared to 2020, meaning the area has eroded more than 2020. In 2020, sediments were mainly moved northward and deposited on the coast of Dokdo by the successive typhoons. On the contrary, the coast of Dokdo was eroded as these sediments moved south again in 2021. Dokdo has been largely affected by the north wind in winter, so sediments mainly move southward. But it is understood that sediments move northward when affected by strong typhoons. Such continuous coastal change monitoring and analysis results will be used as important data for longterm conservation policies in relation to topographical changes in Dokdo.

• Korean Journal of Ecology and Environment
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• v.49 no.2
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• pp.142-146
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• 2016

The purpose of this study is to evaluate topographic characteristics revealed in the predicted distribution areas of Aporia crataegi, according to climate change. Towards this end, this study compared the differences of topographic factors, such as altitude, mountain slope and the aspect of slope, in the distribution areas with different potential inhabitation possibilities of the Aporia crataegi. The inhabitation possibilities of the Aporia crataegi were different, according to altitude and topographic slope, and the inhabitation possibility is judged to be affected more by the topographic conditions including altitude and mountain slope than by the aspect of slope. Especially, the inhabitation possibility of the Aporia crataegi was higher in the higher altitude area, as time goes on furthermore. The reason is that the current climate environment, which is suitable for the potential inhabitation of the Aporia crataegi, is forecast to be formed with an area with high altitude. Although the difference in the aspect of slope was not statistically significant according to inhabitation possibility, the reason why the inhabitation possibility of the Aporia crataegi varies in the mainly southeast slope is conjectured to be derived from the warmer heat environmental condition to grow from a larva into an imago. The result drawn in this study is expected to be utilized as basic data to establish a policy soundly preserving and managing the habitat of biospecies in consideration of climate change and topographic conditions in the natural ecosystem field by using the already built up various biological resources information.

• Tunnel and Underground Space
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• v.23 no.5
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• pp.353-361
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• 2013

Previous studies for analyzing optimal haulage routes of dump trucks in open pit mines mostly used raster data. However, the raster data has several problems in performing optimal route analyses: (1) the jagged appearance of haulage roads according the cell resolution often causes overestimation of the travel cost; (2) it difficult to trace the topological relationships among haulage roads. These problems can be eliminated by using vector network data, however a new method is required to reflect the performance characteristics of a dump truck according to terrain gradient changes. This study presents a new method to create vector network data with the consideration of terrain gradient for analyzing optimal haulage routes of dump trucks in open pit mines. It consists of four procedures: (a) creating digital elevation models, (b) digitizing haulage road networks, (c) calculating the terrain gradient of haulage roads, and (d) calculating the average speed and travel time of a dump truck along haulage roads. A simple case study at the Roto South pit in the Pasir open pit coal mine, Indonesia is also presented to provide proof that the proposed method is easily compatible to ArcGIS Network Analyst software and is effective in finding optimal haulage routes of dump trucks with considering terrain gradient in open pit mines.

• The Journal of the Petrological Society of Korea
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• v.26 no.3
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• pp.167-181
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• 2017

Cheongryangsan area ($49.51km^2$) has been designated as the Provincial Park in 1982, because it has magnificent aspect and seasonally spectacular landscapes. Especially, Cheongryangsa sitey ($4.09km^2$) has been designated as Noted Scenery No. 23 in 2007, because it has the same topographical landscape as rock cliffs, rock peaks and caves. The most spectacular landscapes are exhibited in the Cheongryangsan Conglomerate and Osipbong Basalt. There are twelve rock peaks on the ridges of the two strata, and many rock cliffs in the several valleys of strata, in which a few caves are formed by differential weathering and erosion. The valleys, in which flow Cheongryang, Bukgok and Cheonae streams, are classified as fault valleys along WNW-ESE faults. The rock cliffs were generated from vertical joints parallel to WNW-ESE faults in the two strata, and the caves were formed by differential weathering and erosion along bedding of sandstones and shales intercalated in the conglomerates. The rock peaks are landscapes formed by differential erosion along crossed vertical joints in the ridges. The vertical joints are developed subparallel to two WNW-ESE faults and a NNE-WWS fault. Therefore the topographical features are caused by existence of the faults and Lithologic difference in the Cheongryangsan Conglomerate and Osipbong Basalt, and by differential weathering and erosion along them.