• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.23 no.1
• /
• pp.89-96
• /
• 2005

With acquisition of satellite image being facilitated due to recent advancement in Electro optical and astronautic technologies, focus on establishment of Geoinformation and analysis using satellite images have increased. This research have conducted digital plotting and digitizing operation, utilizing stereo images and grey level images provided by SPOT5 satellite and evaluated the accuracy through comparison and analysis with digital map results. Digital plotting results acquired using stereo images have been compared and analyzed on the basis of scale 1:25,000 digital map results published by National Geographic Information Institute. Accuracy of 20 check points have showed RMSE results 5.369 m at X (Easting) and 4.718 m, digitizing using grey level images showed RMSE results 7.616 m in X (Easting) and Y (Northing) 6.532 m. This is within the allowance of accuracy standards for scale 1:25,000 maps, and although digitizing operation was confirmed to have lower accuracy than that of digital plotting, using the former is considered to be more effective in terms of economical efficiency.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.15 no.1
• /
• pp.197-210
• /
• 2012

The KOrea Multi-Purpose SATellite(KOMPSAT)-2 has a capability to provide a cross-track stereo imagery using two different orbits for generating various spatial information. However, in order to fully realize the potential of the KOMPSAT-2 stereo imagery in terms of mapping, various tests are necessary. The purpose of this study is to evaluate the possibility of mapping using the KOMPSAT-2 stereo imagery. For this, digital plotting was conducted based on the stereoscopic images. Also the Digital Elevation Model(DEM) and an ortho-image were generated using digital plotting results. An accuracy of digital plotting, DEM, and ortho-image were evaluated by comparing with the existing data. Consequently, we found that horizontal and vertical error of the modeling results based on the Rational Polynomial Coefficient(RPC) was less than 1.5 meters compared with the Global Positioning System(GPS) survey results. The maximum difference of vertical direction between the plotted results in this study and the existing digital map on the scale of 1/5,000 was more than 5 meters according as the topographical characteristics. Although there were some irregular parallax on the images, we realized that it was possible to interpret and plot at least seventy percent of the layer which was required the digital map on the scale of 1/5,000. Also an accuracy of DEM, which was generated based on the digital plotting, was compared with the existing LiDAR DEM. We found that the ortho-images, which were generated using the extracted DEM in this study, sufficiently satisfied with the requirement of the geometric accuracy for an ortho-image map on the scale of 1/5,000.

• The Bulletin of The Korean Astronomical Society
• /
• v.33 no.2
• /
• pp.42.2-42.2
• /
• 2008

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.3 no.1
• /
• pp.35-41
• /
• 1983

The purpose of this study is to provide a method of estimating the frequency of flood magnitudes in ungauged station. Six major station are selected for this study in the Geum River system. For each gauging station in the basin, T-year flood is determined by Weibull plotting position. The derivation of the flood frequency formulae is performed on the basis of estimating method of floods with using the hydrological and geomorphical factors developed by U.S. Geological Survey. It is found that the model in this study can be applied to flood flow estimation of ungauged station in the Geum River basin because the mean characteristics of flood flow is used for the basin.

• Journal of Korean Society for Geospatial Information Science
• /
• v.18 no.2
• /
• pp.131-138
• /
• 2010

To manage the architecture information of Seoul, aerial photographs have been taken and Photographic Interpretation Status Maps(PISP) have been produced through interpretation process. However PISP of SEOUL has a number of errors and difficulties to update maps, owing to its analogue formation by hand skill. In this study, some digitizing methods are tested to make Digital Photographic Interpretation Status Maps(DPISP). The digitizing methods by scanning maps, using ortho-images and true ortho-images, digital correction plotting process, and LiDAR techniques were used for comparative analysis of PISP. As a result of this study, the author suggest DPISP by the digital correction plotting method is proper for economical efficiency and its accuracy of the architecture information.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1999.10c
• /
• pp.479-485
• /
• 1999

This study was conducted to derived design floods by Generalized Extreme Value(GEV) distributiion for the annual maximum series at ten watersheds along Han, Nagdong, Geum , Yeongsan and Seomjin river systems. Adequency for the analysis of flood data used in this study was established by the test of Independence, Homogeneity , detection of Outliers. Coefficient of variation , skewness and kurtosis were calculated by the L-Moment, and LH-Moment ratio respectively. Parameters were estimated by the Method of L-Method of LH-Moment. Design floods obtained by Method of L-Moments and LH-Moments using different methods for plotting positions in GEV distributions and were compared with those obatined using the Method of L-Moments and LH-Moments by the Relative Mean Errors and Realtive Absoulte Errors. It was found that desgin floods derived by the method of L-Moments and LH-Moments using Cunnane plotting position foumula in the GEV distribution are much closer to those of the observed data in comparison with those obtained by methods of L-moments and LH-moments using the other formula for poltting postions from the viewpoint of Relative Mean Errors and Relative Absoulte Errors. In view of the fact that hydraulic structures indcluding dams and levees are generally usiong design floods with the return period of two hundred years or so, design floods derived by LH-Moments are seemed to be more reasonable than those of L-Moments in the GEV distribution.

• International Journal of Ocean System Engineering
• /
• v.1 no.1
• /
• pp.52-59
• /
• 2011

A prototype radar display unit was implemented using inexpensive off-the-shelf components, including a nonlinear estimation algorithm for the target tracking in a clutter environment. Two custom designed boards; an analog signal processing board and a DSP board, can be plugged into an expansion slot of a personal computer (PC) to form a maritime radar display unit. Our system provided all the functionality specified in the International Maritime Organization (IMO) resolution A422(XI). The analog signal processing board was used for A/D conversion as well as rain and sea clutter suppression. The main functions of the DSP board were scan conversion and video overlay operations. A host PC was used to run the tracking algorithm of targets in clutter, using the discrete-time Bayes optimal (nonlinear, and non-Gaussian) estimation method, and the graphic user interface (GUI) software for Automatic Radar Plotting Aid (ARPA). The proposed tracking method recursively found the entire probability density function of the target position and velocity by converting into linear convolution operations.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.20 no.2
• /
• pp.127-136
• /
• 2002

DEM(Digital Elevation Model) is used widely in image processing, water resources, construction, GIS, landscape architecture, telecommunication, military operations and other related areas. And it is used especially in producing ortho-photo based on specific DEM and developing 3D GIS database vividly. As LiDAR(Light and Detection And Ranging) system emerged recently, DEM could be developed in urban area more efficiently and more economically, compared to the conventional DEM Production. Traditional method using check points for elevation has tome limitations in structure's height accuracy by LiDAR, because it uses only terrain height. Accordingly after the downtown of Chungju city was selected as a test field in this paper and DEM and digital ortho images was produced by way of LiDar survey, the accuracy was evaluated through analytical plotting map. The result shows that in case of buildings in LiDAR DEM, the accuracy is 0.30 m in X, 0.62 m in Y and RMS is 1.17 m. The difference distribution between DEM and plotting map in range of $\pm$10 cm was 36.2% and $\pm$10 cm $\pm$20 cm was 43.53%. The accuracy of LiDAR in this study meets 1/5,000 which is the regulation for map of NGI(National Geography Institute) and LiDAR can be possibly used in many other applied area.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• v.18 no.3
• /
• pp.209-224
• /
• 2014

In this paper, the solution of time fractional telegraph equation is obtained by using Adomain decomposition method and compared with various other method to determine the efficiency of Adomain decomposition method. These methods are used to obtain the series solutions. Finally, results are analysed by plotting the solutions for various fractional orders.

• Journal of the Korean Institute of Navigation
• /
• v.12 no.1
• /
• pp.27-43
• /
• 1988

The tedious work, connected to the altitude correction, the computation of altitudes and aximuths and the plotting of the position lines, has been a objection to celestial position fixing method. But using a computer , the severe objection will be practically overruled. The author had already studied on computerization of the sight reduction partially. This paper is to confirm reliability of coordinate of the moon and the navigational planet calculated by computer programming and to suggest a method of calculating ship's position fixed by two position lines.