• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.12 no.1
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• pp.43-52
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• 1994

This paper outlines a new approach to the line generalization when preparing small scale map on the basis of existing large scale digital map. Line generalizations are conducted based on Douglas algorithm using 1/25,000 scale topographic maps of southeastern JEJU island which produced by National Geographic Institute to analyze the fitness to the original and problems of graphical representation. Compare to the same scale map which was generated by manual method, a verity of small, but sometimes significant errors ＆ modification of topological relationship have been detected. The research gives full details of three algorithms that operationalize the smallest visible object method, together with some empirical results. A comparison of the results produced by the new algorithms with those produced by manual generalization and Douglas method of data reduction is provided. Also this paper presents the preliminary results of an relationships between the size of smallest visual object and requiring data storages for each algorithms.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.04a
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• pp.139-142
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• 2010

ENC(Electronic Navigational Chart) is an electronic chart that digitize nautical chart including all kinds of information of nautical chart. Mariners have difficulty reading information because of clutter problem if display scale of ECDIS is lower than compilation scale of ENCs. IHO made SCAMIN improvement model included in S-65 Standard to settle this ENC clutter problem. This SCAMIN model includes both simple restriction that should safety some requirement and share geographic information. and hard restriction that should overlap with area object such as depth area, land area, dredge area. It also apply SCAMIN step of sounding value according to importance of safety navigation. In this paper, we analyzed the restrictions for SCAMIN model of S-65 Standard, developed algorithm and application to apply theses restrictions reasonably and mechanically. Also we applied this algorithm and application to Korea ENCs and evaluated the result of performance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.11
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• pp.2403-2412
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• 2010

ENC(Electronic Navigational Chart) is an electronic chart including all kinds of information of nautical chart. Mariners have difficulty reading information because of clutter problem if display scale of ECDIS is lower than compilation scale of ENCs. IRO made SCAMIN improvement model included in S-65 Standard to settle this ENC clutter problem. This SCAMIN model includes both simple restriction that should satisfy some requirement and share geographic information, and hard restriction that should overlap with area object such as depth area, land area, dredge area. It also apply SCAMIN step of sounding value according to importance of safety navigation. In this paper, we analyzed the restrictions for SCAMIN model of S-65 Standard, developed algorithm and application to apply theses restrictions reasonably and mechanically. Also we applied this algorithm and application to Korea ENCs and evaluated the result of performance.

• Journal of the Korean Association of Geographic Information Studies
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• v.12 no.4
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• pp.169-181
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• 2009

IMO adopt the revision of SOLAS convention on requirement systems for ECDIS and considered an ECDIS as the major system for E-Navigation strategy on marine transportation safety and marine environment protection. ENC(Electronic Navigational Chart) as base map of ECDIS is considered as a principal information infrastructure that is essential for navigation tasks. Though ECDIS has many advantages, it's almost impossible for the mariner to recognize the displayed information because of intense display of objects so called the clutter. In this paper, the current status and international standards on SCAMIN((Minimum Scale) attribute have been investigated. Also improvement of SCAMIN attribute of ENCs and grouping method for the sounding values was proposed.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.24 no.4
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• pp.313-318
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• 2006

Recently, the single plane coordinate system which has one origin is required to create and manage continuous geographic framework data of entire Korean peninsula. For this, UTM-K (Univercial Transverse Mercator-K) was established in 2005. In this paper, the level of distortion was analyzed with respect to the central meridian and scale factor of UTM-K. The latitude and longitude values of the center point of 1/25000 scale digital maps were used for calculating the scale factor which was created by projection and the scale factor was used for index that presents the degree of distortion. As a result, accumulated distortion of scale factor by UTM-K map projection showed about $23.744{\times}10^{-2}$. On the other hand, the minimum distortion which was about $5.1435{\times}10^{-2}$ occurred when central meridian is $127^{\circ}\;42'$ and scale factor of central meridian was 0.99994 respectively.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.1
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• pp.39-45
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• 2007

In this paper, a research has been conducted to find out the optimal combination of central meridian and scale factor of UTM-K to apply for the whole area of Korean peninsula. For this research, various combinations of central meridian and stale factor are set up and the cumulated level or distortion for each combination has been computed and compared to each other. In the case of using the central meridian and scale factor defined in the present UTM-K, the level of distortion shows about $47.0837{\times}10^{-2}$. On the other hand, the minimum distortion which is about $21.0495{\times}10^{-2}$ can be obtained when the $127^{\circ}26'$ for the central meridian and 0.99991 for scale factor are used for computation. Consequently, we can conclude that later result is the optimum combination of central meridian and scale factor for the Korean peninsula.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.22 no.2
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• pp.137-143
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• 2004

The electronic distance measurement(EDM) instrument, introduced first in the 1950s since those early days has, undergone continual refinement. Rapid advances established in related technologies have made it lighter, smaller and more precise equipment. Understanding for the principle, the standardized observation technique and the precision of EDM instrument is mostly important to improve the quality and the reliability of by-product in the field of engineering and industrial surveying. Periodical and accurate calibration is necessary to maintenance the precision of EDM instrument. This paper describes the calculated example of zero error and scale error as a correction of EDM by applying the least square method to baseline observations in test area. Also here we deal with the testing criteria for precision instrument testing according to different types of EDM instruments.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.5 no.4
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• pp.271-278
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• 1993

Sand ripple. the smallest bottom configuration, is one of the most important factors in the mechanism of sand transport. This paper deals with characteristics of ripple geometry generated by regular and irregular waves. Especially. rearrangement of ripple spacing caused by increasing or decreasing waves is investigated through movable bed experiments. Nondimensional length of rearranged ripples becomes very close to that of measured ripples in the field Furthermore, stochastic characteristics and occurrence limits of three dimensional ripples are investigated through the wave number spectrum calculated from the measured bottom topography.

• Korean Journal of Remote Sensing
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• v.12 no.1
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• pp.17-25
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• 1996

This paper presents a GCP marking technique using scanned maps. Twelve maps with a scale of 1:250, 000 were scanned and stored as raster images. The distortion factors of scanned maps were modelled by polynomials. The coefficients of the polynomials were determined by a least squre fit. This technique does not require a bulky and expensive digitizing table so that it is suitable for a low-cost pre-processing system. The GCP marking using this technique showed a sufficient accuracy for KITSAT1, 2 narrow camera images.

• Journal of the Korean Association of Geographic Information Studies
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• v.1 no.1
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• pp.39-51
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• 1998

The purpose of this study is to find out the ways to supplement the Census, the digital maps, and their integration in comparison with the U.S. Census and the TIGER file and in light of their usefulness for urban and environmental analysis in Korea. Recommendations in this study are: (1) to include questions on household income and housing price in the Census, (2) to implement a 1~5% sampling survey similar to PUMS in the U.S. Census, (3) to make the Census Tract as a minimum size unit of analysis through subdivision of current Eup, Myon, and Dong into 5~10 smaller units, and (4) to utilize the 1:5,000 scale digital maps completed by the Korea National Geographic Institute for the fast and efficient activation of digital maps instead of producing 1:1,000 or 1:1,200 scale digital maps through each city's effort.