• Journal of the Korean Association of Geographic Information Studies
• /
• v.5 no.3
• /
• pp.19-32
• /
• 2002

Topographic information is indispensable in the applications that require elevational data. These applications are exemplified by watershed partition, extraction of drainage networks, viewshed analysis, derivation of geomorphologic features, quantification of landslide-terrain, and identification of topographic settings susceptible to landsliding. Therefore, we study the accuracy of data on topographic parameters derived from digital elevation models(DEMs). This research wished to analyze the effect that data source and grid size get in topography parameter using gridded DEM. An analysis of topography parameter extract and compared drainage basin, watershed slope, stream network using DEM is constructed by digital map and DTED DEM. Especially, when extract stream network from gridded DEM, received much effects according to threshold value of flowaccumulation regardless of DEM grid size. Therefore, this study applied equal threshold value of flowaccumulation for two data sources, and compare and analyzed stream network.

• Journal of the Korean Solar Energy Society
• /
• v.35 no.2
• /
• pp.1-10
• /
• 2015

Promising onshore wind farm sites in Gangwon province of Korea were investigated in this study. Gangwon province was divided into twenty five simulation regions and a commercial program based on Reynolds averaged Navier-Stokes equation was used to find out wind resource maps of the regions. The national wind atlas with a period 2007-2009 developed by Korea institute of energy research was used as climatologies. The wind resource maps were combined to construct a wind resource map of Gangwon province with a horizontal spatial resolution of 100m. In addition to the wind resource, national environmental zoning map, distance from substation, residence and automobile road, Beakdudaegan mountain range, terrain slope, airport and military reservation district were considered to find out promising wind farm sites. A commercial wind farm design program was used to find out developable wind farm capacities in promising wind farm site with and without excluding environmental protection regions. The total wind farm capacities with and without excluding the protection regions were estimated to be 46MW and 598MW, respectively, when a 2MW commercial wind turbine was employed.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.20 no.2
• /
• pp.111-118
• /
• 2002

These days, surveying instruments are developing rapidly and the precision is improving continuously. The building of three dimensional terrains of high precision are possible and the calculation of the areas or the volumes have high precision due to the development of the technique of the spatial information system using computer. But actually, in construction site they calculate two-dimensional area using the traditional method, plate table surveying, planimeter, and then get three-dimensional area through multiplying two-dimensional area by the slope correction factor. In this study, we show the defect and inefficiency of the calculation of area by the traditional methods and survey the area with Electric Distance Measurement and GPS instrument. With this data, we made the three dimensional terrain model and calculated two-dimensional area, three-dimensional area. After that, we compared areas that calculated by algorithm of triangulated irregular network and analysis of grid method with standard area that calculated by the traditional method. Finally, this paper suggested more effective and precious method in calculating three-dimensional area.

• Journal of IKEEE
• /
• v.23 no.3
• /
• pp.883-892
• /
• 2019

This study is the method which is adapted to control ankle joint movement for resolving the problem of gait imbalance in intervals where gait environments are changed and slope walking, as applying terrain-adaptive technique to intelligent above-knee prosthesis. In this development of above-knee prosthesis, to classify the gait modes is essential. For distinguishing the stance phases and the swing phase depending on roads, a machine learning which combines decision tree and random forest from knee angle data and inertial sensor data, is proposed and adapted. By using this method, the ankle movement state of the prosthesis is controlled. This study verifies whether the problem is resolved through butterfly diagram.

• Journal of The Geomorphological Association of Korea
• /
• v.25 no.1
• /
• pp.1-17
• /
• 2018

The characteristics and burial ages of sand sediments on the Jiduri coast in Daechung-myeon, Ongjin-gun, Incheon were investigated. Daecheong Island is the area where the characteristics of the rocky coast and sand coast are shown. Various studies have been conducted on the Okjukdong sand dune that appears in the north of the island. However, there has been no study on the sandy sedimentary topography of the Jiduri and Moraewul area in the south. The sandy sedimentary terrain of Jiduri is divided into sandy beaches, sand dunes and sand deposits along the slope including climbing dune. Overall, the depth of sandy sediments in Jiduri is not deep. The characteristics of sandy sediments and burial ages were investigated at an elevation of about 23 m above sea level at the back of Jiduli Beach and 46 m above sea level at the ridge line between Jiduri and Moraewol. From the Jiduri coast to the hillside behind, the average grain size decreases and the sorting becomes better as it moves from the intertidal zone to the beach and the foredune. This indicates the selective sand transport by the wind and can be judged by the terrain formed under the current sedimentation environment. The average grain size at the upper part of the section of JD-1 (elevation of about 23m MSL) was $1.6918{\varphi}$ of medium sand. The sorting was $0.4584{\varphi}$, skewness was -1.0491 and kurtosis was -1.2411, respectively. Particularly, the average particle size of the crosssection issomewhat uniform, but the color of the constituent material changes from brown to black. In the case of JD-2 (about 46 m MSL), the mean grain size of the section was $1.7943{\varphi}$, the sorting was 0.4931, the skewness was -1.1163, and the kurtosis was 1.2133. On the other hand, the brown and black layers of JD-1 exhibited a burial age of $0.1{\pm}0.0ka$ and the JD-2 had a burial age of $0.7{\pm}0.0ka$.

• Journal of the Korean Geographical Society
• /
• v.49 no.5
• /
• pp.656-674
• /
• 2014

The objective of this study was to examine the distinctiveness and generality of landforms of the Korean peninsula, and further discover geomorphological principle that can be applied to land and environmental management in Korea. The research targeted East Asia and Korea, with terrain analysis conducted at a continental scale, national scale, and regional scale sequentially. East Asia displays complicated characteristics and evolutionary history of geotectonics, but exhibits distinct northeast-southwest geomorphological structure and connectivity at the continental level. While the Korean peninsula follows this pattern on a continental scale, it also features NNW-SSE direction (Nangrim and Taebaek Mountains) geomorphological connectivity that intersects at a right angle. From a national perspective, the Korean peninsula hosts the most diverse geomorphological features within East Asia. It does not have a high average altitude, but has relatively high slope angle and intricate topographical distribution in comparison to neighboring areas. While the mountains and plains of the Korean peninsula display a smooth connection, geomorphologically similar areas such as Shikhote-Alin, Huanan in China, and Japan have clear characteristics that divide the mountains and plains. Despite the distinctiveness and diversity that appear in East Asian topography on the regional scale, the connectivity that links the top of mountain (hill) to stream is identical among all areas as a general rule. It is collectively considering the connectivity and the geomorphological and ecological processes that arise within this connectivity that will serve as the focal point for sustainable landscape management.

• The Journal of Engineering Geology
• /
• v.23 no.1
• /
• pp.57-65
• /
• 2013

We developed a computer program (CDFlow v. 1.0) to design countermeasures against debris flows in natural terrain. The program can predict the probability of landslides occurring in natural terrain and can estimate the zone of damage caused by a debris flow. It can also be used to design the location and size of countermeasures against the debris flow. The program is run using the ArcGIS Engine, which is one of the most well-known Geographic Information System (GIS) tools for developers. The quasi-dynamic wetness index and the infinite slope stability equation were applied to predict landslide probability as a type of slope safety factor. The calculated safety factor was compared with the required safety factor, and areas of high probable potential for landslides were then selected and represented on the digital map. The volume of debris flow was estimated using these areas of high probable potential for landslides and soil depth. The accumulated volume of debris flow can be calculated along the flow channel. To assess the accuracy of the program, it was applied to a real landslide site at Deoksan-ri, Inje-gun, Kangwon-Province, where four debris barriers have been installed in the watershed of the site. The results of soil tests and a field survey indicate that the program has great potential for estimating probable landslide areas and the trajectory of debris flows. Calculation of the capacity volume of existing debris barriers revealed that they had insufficient capacity to store the calculated amount of debris flow. Therefore, this program enables a rational estimation of the optimal location and size of debris barriers.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.16 no.4
• /
• pp.297-303
• /
• 2014

The effect of solar irradiance has been used to estimate daily maximum temperature, which make it possible to reduce the error inherent to lapse-rate based elevation difference correction in mountainous terrain. Still, recent observations indicated that the effect of solar radiation would need correction for estimation of daily maximum temperature. It was attempted to examine what would cause the variability of solar irradiance effect in determination of daily maximum temperature under natural field conditions and to suggest improved methods for estimation of the temperature distribution over mountainous regions. Temperature at 1500 and the wind speed for 1100 to 1500 were obtained at 10 validation sites with various topographical features including slope and aspect within a mountainous $50km^2$ catchment for 2012-2013. Lapse-rate corrected temperature estimates on clear days were compared with these observations, which would represent the differential irradiance effect among sloped surfaces. Results indicated a negative correlation between the mean wind speed and the estimation error. A simple scheme was derived from relationship between wind speed and estimation error for daily temperature to correct the effect of solar radiation. This scheme was incorporated into an existing model to estimate daily maximum temperature based on the effect of solar radiation. At 10 validation sites on clear days, estimates of 1500 LST temperature with and without the correction scheme were compared. It was found that a substantial improvement was achieved when the correction scheme was applied in terms of bias correction as well as error size reduction at all sites.

• Journal of Cadastre & Land InformatiX
• /
• v.48 no.1
• /
• pp.153-167
• /
• 2018

Despite many criticisms that topographic survey data for the official land price appraising collected annually using field survey method might be inaccurate, there is only few concrete research on it. This paper investigated whether the topographic survey data collected by a local government using field survey method is consistent with the data analyzed using the digital elevation model to examine its accuracy. The accuracy analysis indicated that 324 out of 1537 lots of land have inconsistent results which means the ratio of inconsistency is 17.36%. Among 11 areas studied, five had the inconsistency ratio above 20% while the worst one had 38.71%. The inconsistency ratio is generally higher for the rough terrain with irregular slope and high altitude while it is relatively lower for the terrain with smooth landform. The analysis results imply that there are limitations in investigating the topology by field survey method. Therefore, the official land price appraising policy should set precise criterion and change over to highly accurate geographic information analysis method to effectively and accurately examine topology, given the fact that the topology of the Republic of Korea has complicated features with irregular slope and altitude.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.8 no.2
• /
• pp.45-51
• /
• 1990

DEM must have a high accuracy against the actual topographic model. A model which can compute heights responding to random plane position by using of the topographic data and interpolation must be constructed. Interpolation affected by the accuraccy of the observations included noise, which affected by the slop and curvature weight. Data smoothing is a method to reduce the noise. Average declination and area ratio are variable which result similarity in according to slope. But in local area, area ratio well shows a local change. This study try to classify the terrain by the declination to analysis the effects of the declination and curvature weights, and then to represent the most probable model. The result are following : In terrain classification by the slop, p16 and p24 were fitted in the plane surface fit p16 and S in the varying surface, and S and p24 in the irregular surface in classification by curvature, p24 and S were fitted in the plane or varying surface, and p16 in the irregular surface In case of hybrid, p16, p24 and S are fitted in the plane, varying and irregular surface respectively. Smoothing is the most effective in case of slope of 50 persentage and of curvature weight of 0.0015.