• Journal of Korean Society of Rural Planning
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• v.15 no.4
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• pp.213-220
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• 2009

Farmland spatial data are needed as a basic information in conducting rational use of farmlands in regional scale. This study develops a method that can be used to make up such farmland spatial data in a simple way and to develop a technique to manage them in a unitary way, and examines the effectiveness of the technique by applying it to the case area. A method that Web-Service Raster Image and Digital Cadastal Map can be utilized as a base map was devised. It was designed applying the vector system, in which one lot of farmland is area unit. Raster image and field survey data were combined to increase the accuracy of data. The lot boundaries of the existing boundary map were adjusted to the shapes of actual farmlands using GIS edition function. A proper farmland use classification system to the area characteristics was established and data obtained from the field survey were coded. Usually it is very difficult to identify the size of one lot of actual farmland in the existing space data, based on the results of the case study, the result map showed actual topography very realistically. Also the frequently occurring lot divisions and the serious topographical modifications by natural disasters frequently have made it impossible to survey farmlands on the catastral map in the field. But the final map had a great usefulness in that it may solve such problems by expressing the filed survey results graphically.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.3
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• pp.217-223
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• 2014

With precise sensor position, attitude element, and imaging resolution, a simulated geospatial image can be generated. In this study, a satellite image is simulated using SPOT ortho-image and global elevation data, and the geometric similarity between original and simulated images is analyzed. Using a SPOT panchromatic image and high-density elevation data from a 1/5K digital topographic map data an ortho-image with 10-meter resolution was produced. The simulated image was then generated by exterior orientation parameters and global elevation data (SRTM1, GDEM2). Experimental results showed that (1) the agreement of the image simulation between pixel location from the SRTM1/GDEM2 and high-resolution elevation data is above 99% within one pixel; (2) SRTM1 is closer than GDEM2 to high-resolution elevation data; (3) the location of error occurrence is caused by the elevation difference of topographical objects between high-density elevation data generated from the Digital Terrain Model (DTM) and Digital Surface Model (DSM)-based global elevation data. Error occurrences were typically found at river boundaries, in urban areas, and in forests. In conclusion, this study showed that global elevation data are of practical use in generating simulated images with 10-meter resolution.

• Korean Journal of Geomatics
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• v.2 no.1
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• pp.57-64
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• 2002

Measuring the depth of water is very important in ensuring the protection and safety of seaside. There are many difficulties in making the contour bathymetric map, and contour line due to the limitation of continuous measurement of water depth and collimation with the conventional measuring and positioning methods. But the real-time kinematic GPS (RTK GPS) positioning using a carrier phase enables us to decide a precise position without breaking a signal even under the condition of a moving environment. It is also possible to obtain an accurate depth of water in real time with a fathometer through the measuring of time delay between sending and receiving epochs. This research aims at investigation of accuracy potential of RTK GPS in combination with Echo Sounder(E/S) for the coastal mapping. Apart from this purpose, the accuracy of ambiguity resolution with the OTF(On the Fly) method was tested with respect to the initialization time. The result shows that the accuracy is better than 1cm with 5-minute initialization in the distance of 10km baseline. The seaside topography was measured by the RTK GPS only, on the other hand the seafloor topography was surveyed in combination of RTK GPS and E/S. Comparing to the volume of seaside measured by RTK GPS and digital topographical map, the difference of only 2 % was achieved. This indicates that the coastal mapping with RTK GPS is successfully conducted. In addition it is also demonstrated that the 3-dimensional perspective model resulted from the undersea topography measured by RTK GPS and E/S is very close to that from the digital map. Through this study, it was verified that RTK GPS is to be very useful method in the analysis of coastal morphology owing to its capability of getting the precise DTM for the using of harbor reclamation, dredging, and the estimation of soil movement in a river.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1D
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• pp.121-128
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• 2009

The King George Island, where the King Sejong Station is located, represents one of the gateways to the Antarctica from the point of its geographical aspect. It also serves as an advanced post, and plays an important role in the extending for Korea's Antarctic research activities. The existence of maps is not only a basic element for the constructing geographic informations supporting these activities, but also an implied way of announcing the sovereignty over the KingSejong Station in global world. However, the precise surveying for the geographic information has not been carried out, and thus topographical maps as well as geographic information assuring enough accuracy are still missed in this area. This fact had forced Korea to rely on using maps produced by foreign countries. Therefore, this study aims to generate digital topographical maps of 1: 5,000 scale for the constructing geographic information using lightweight aerial photogrammetry system first. And further, it will contribute to offer practical base data for the future research related to the Antarctic environment through the analysis of glacier retreat and change using this new digital map comparing with existing one.

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

• Journal of Korean Society for Geospatial Information Science
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• v.24 no.4
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• pp.29-38
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• 2016

The maps produced by the NGII(geographical information institute) are composed of 1/1,000, 1/2,500, 1/5,000 large scale maps, 1/25,000, 1/50,000 and smaller scale maps. 1/1,000 digital map, as the most large-scale digital map made by the NGII, has been constructed with the beginning of NGIS(national geographic information System) Project in 1995. However, 1/1000 digital maps have been not produced by the fundamental survey on the basis of systematic planning at the national level, but a lot of parts have been constructed by the public survey for the purpose of the fiscal year of the local governments. Also, these maps have been not regularly updated because of big budget. In this study, we investigated problems related to the construction status, system, and area, and suggested plans that can improve these problems. As the improvement plan, we proposed a nationwide three regionalization for short-term modification and long-term regular update, reset of core downtown boundaries based on topographical features, diversification of budget execution method and an improved execution system.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.2
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• pp.67-74
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• 2018

This study has proposed a methodology to detect suspicious facilities that occupy national and public land by using the cadastral and digital maps. First, we constructed a spatial database of national & public land based on the cadastral maps by linking its management ledger. Using the PNU (Parcel Number) code as a key field, the data managed by different institutions are integrated into a single spatial information DB (database) and then, the use or nonuse state of each parcel is confirmed on the cadastral map. Next, we explored the suspicious facilities that existed in the unused parcel by utilizing the digital topographical map. Then, the proposed methodology was applied for various regions and tested its feasibility. Through this study, it will be possible to improve the utilization of digital maps and to manage the national and public land efficiently and economically.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.3
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• pp.11-22
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• 2005

It is necessary to arrange and analyze the collected research date to get regularity such as characteristics, merits and demerits, and possibility in city when constructing land information by analyzing linkage and utilization of cadastral information as the fundamental data for land information around the acreage of a lot and by expressing the purpose of each digital data construction with map. In short, that is the work to classify data, to make chart or map, or to analyze using statistical technique. Some information in land utilization had been used by computerization, but several problems were found in common use of total divisions. The most important problem is, in the case of drawing information, that topographical map with building boundary and land registration map with acreage boundary cannot be used together. In the case of property information, common utilization of property information that is basically needed and standard measurement of usage classification are necessary. The characteristics of the land usage data by the rearrangement of the cadastral information. etc. is presented as the basic data for the land information orientation, and the analyzing result of the data should be expressed and controlled on the map as the fundamental survey for the establishment of the land information oriented planning supports the physical space planning of the land cadaster finally. In this research, the problem in establishing current land information around acreage of a lot was found to research data to be needed in land information for utilizationof space based digital information, and was studied the method in relation to GIS.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.1
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• pp.117-124
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• 2010

Lots of changes in Weolmido have occurred in the historical and cultural aspects owing w the geographical features. This study aims at restoring Weolmido to the past shape three-dimensionally and analyzing its changes. For achieving this goal, I made use of paper maps made in 1918, 1928, and 1969, a digital map produced in 2008, and aerial photos photographed in 1954. And I attempted to grasp the architectural shape and the topographical limn by using photos in those times and put them to practical use for restitution. Image restitution was carried out under the method of mapping and photogrammetry. As the result of restitution, I could restore each shape of Weolmido for those past times to the original condition three-dimensionally and catch its changes according to the difference of times.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• v.6 no.1
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• pp.22-29
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• 2003

This research aims at investigation of accuracy potential of RTK(Real-Time Kinematic) GPS in combination with Echo Sounder(E/S) for the coastal mapping. Apart from this purpose, the accuracy of ambiguity resolution with the OTF(On The Fly) method was tested with respect to the initialization time. The result shows that the accuracy is better than 1cm with 5-minute initialization in the distance of 10km baseline. The seaside topography was measured by the RTK GPS only, on the other hand the seafloor topography was surveyed in combination of RTK GPS and E/S. Comparing to the volume of seaside measured by RTK GPS and digital topographical map, the difference of only 2% was achieved. This indicates that the coastal mapping. As a result, it has been revealed that every possible noise in surveying could be corrected and the accuracy could be improved. The accuracy of GPS data acquired in real time was as good as that acquired by post processing. It is expected that it will be useful for the analysis of coastal geographic characteristics because DTM(Digital Terrain Model) can be also constructed for the harbor reclamation, the dredging, and the variation of soil movement in a river.