• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.24 no.1
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• pp.131-138
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• 2006

Recently, data gathering and algorithm developing are in progress for the GIS application using point feature. Several researches prove that verification of the spatial clustering and evaluation of inter-dependencies between event and control are possible. On the other hand, most of the point features as GIS data are gathered by indirect method, such as address geo-coding, rather than by direct method, such as field surveying. Futhermore, lots of statistics by administrative district based on the point features have no coordinates information of the points. In this study, calculating the K-index in GIS environment, to evaluate the effect of aggregation of raw data on K-index, K-indices estimated from raw data (parcel unit), topographically aggregated data (block unit), administratively aggregated data (administrative district unit) are compared and evaluated. As a result, point feature, highly clustered in local area, is largely distorted when aggregated administratively. But, the K-indices of topographically aggregated data is very similar to the K-indices of raw data.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.337-343
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• 2004

Spatial information could be obtained from spaceborne high resolution optical and synthetic aperture radar(SAR) images. However, some satellite images do not provide physical sensor information instead, rational polynomial coefficients(RPC) are available. The objectives of this study are: (1) 3-dimensional ground coordinates were computed by applying rational function model(RFM) with the RPC for the stereo pair of Ikonos images and their accuracy was evaluated. (2) Interferometric SAR(InSAR) was applied to JERS-1 images to generate DEM and its accuracy was analysis. (3) Quality of the DEM generated automatically also analyzed for different types of terrain in the study site. The overall accuracy was evaluated by comparing with GPS surveying data. The height offset in the RPC was corrected by estimating bias. In consequence, the accuracy was improved. Accuracy of the DEMs generated from InSAR with different selection of GCP was analyzed. In case of the Ikonos images, the results show that the overall RMSE was 0.23327", 0.l1625" and 13.70m in latitude, longitude and height, respectively. The height accuracy was improved after correcting the height offset in the RPC. i.e., RMSE of the height was 1.02m. As for the SAR image, RMSE of the height was 10.50m with optimal selection of GCP. For the different terrain types, the RMSE of the height for urban, forest and flat area was 23.65m, 8.54m, 0.99m, respectively for Ikonos image while the corresponding RMSE was 13.82m, 18.34m, 10.88m, respectively lot SAR image.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.1
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• pp.178-189
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• 2008

The purpose of this study is to look into the necessity of strengthening the knowledge base about longitudinal and latitudinal coordinate system in secondary educational curriculum. GPS based location service increases the use of longitude and latitude coordinate system. And many developed countries including USA and Japan have already included this contents in secondary education curriculum. But the secondary school Curriculum of Korea does not include the detailed contents regarding longitudinal and latitudinal coordinate system theory, and as a result the level of Korean students knowledge on this subject is low. The frequency of appearing of the information related to longitudinal and latitudinal coordinate systems in newspaper articles in Korea has been steadily increasing since after 2000. And a lot of articles appearing in newspapers provide the location information in the form of longitude and latitude coordinates, so the readers would be able to apply that. It was found out that the situation in schools is developed good enough for the use of spatial information system based upon the longitudinal and latitudinal coordinate system. The conclusion is that geography education in Korea needs systematical implementation of the knowledge base of longitudinal and latitudinal coordinate system.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.4
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• pp.101-107
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• 2013

Generally the commercial high-resolution images have their coordinates, but the locations are locally different according to the pose of sensors at the acquisition time and relief displacement of terrain. Therefore, a process of image co-registration has to be applied to use the multi-temporal images together. However, co-registration is interrupted especially when images include the cloud-covered regions because of the difficulties of extracting matching points and lots of false-matched points. This paper proposes an automatic co-registration method for the cloud-covered high-resolution images. A scale-invariant feature transform (SIFT), which is one of the representative feature-based matching method, is used, and only features of the target (cloud-covered) images within a circular buffer from each feature of reference image are used for the candidate of the matching process. Study sites composed of multi-temporal KOMPSAT-2 images including cloud-covered regions were employed to apply the proposed algorithm. The result showed that the proposed method presented a higher correct-match rate than original SIFT method and acceptable registration accuracies in all sites.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.4
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• pp.181-188
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• 2010

For a proper use of the integrated real estate information, there must be a process on linking the information of buildings and land data. This study aims to enhance the location information of the buildings on the digital topographic map by assigning the coordinates on the building layout plan of the Building Registers which does not have a positional information based on the cadastral boundary of the cadastral map. Also, the land and building attribute information are managed in various official registers and systems which are overlapped each other. The overlapped information must be corrected based on legislation. Therefore this study introduces a comprehensive attribute information excluding any overlapped information. In other words, this study proposes a single advanced real estate information by integrating the attribute information and the separated real estate information(buildings and land).

• Journal of Korean Society of Disaster and Security
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• v.9 no.2
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• pp.15-21
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• 2016

According to the disaster statistics issued by the Ministry of Public Safety and Security, traffic accidents, fire, collapses and others are classified into twenty-three (23) categories. In the past, disasters were mainly caused by the influence of nature, such as typhoon or drought. On the other hand, as society has become city-centered, social disasters' types, frequencies and scales are becoming more diversified and ever-increasing. However, there are no specific criteria and assessment methods that can measure degrees of social disasters-related risks objectively. Therefore, this study targeted traffic accidents, fire and collapses from major social disasters, utilized data that are related to occurrence rate, scale of casualties and scale of property loss in past eight years, and calculated the disaster risk index using the distance (Euclidean distance) between two points on the 3D spatial coordinates, in order to make the objective assessment by social disaster type possible. These results will enable the objective evaluation of risk index of major social disaster to be used as the foundational data when building the national disaster management system.

• Journal of Cadastre & Land InformatiX
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• v.45 no.2
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• pp.117-130
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• 2015

A least squares method for adjusting the horizontal network satisfies the conditions which is minimizing the sum of the squares of errors based on probability theory. This research compared accuracy of 3rd cadastral control points adjusted by traditional and least square method with respect to the result of Network-RTK. Test results showed the least square method more evenly distribute closure error than traditional method. Mean errors of least square and traditional adjusting method are 2.7cm, 2.2cm respectively. In addition, blunder in angle observations can be detected by comparing position errors which calculated by forward and backward initial coordinates. However, distance blunder cannot offer specific observation line occurred mistake because distance error propagates several observation lines which have similar directions.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.1
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• pp.28-34
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• 2010

The spatial distribution characteristics of damaged trees by the pine wilt disease appear scattered spots spreading from single dead trees. That is the reason why it is difficult to early detect damage and to prevent from extensive damage. Thus, it is very important to forecast and analyze the damage occurrences, to establish strategies for prevention, and to supervise them. However, conventional survey which observes around roads or residential areas by naked eyes was impossible to investigate completely, missing target areas and dangerous areas. Therefore, aerial forecasting techniques on the damaged area were developed using GIS, GPS, and helicopters for an accurate observation of systematic and scientific approach in this study. Moreover, advantages of the techniques application were confirmed to survey 972 dead tree samples at 349 position-coordinates in 32 cities (about $28,810km^2$), 2005. This study is expected to apply widely to find dead trees and the causes, particularly by pine wilt disease.

• Journal of Cadastre & Land InformatiX
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• v.46 no.2
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• pp.313-323
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• 2016

Recently, "Cadastral Confirmation Surveying" has been established to promote efficiently and systematically its work. To do so, it is necessary that cadastral control point should be set up and transverse grid coordinates should be determined for high accuracy and boundary restoration based on the cadastral control point. This study expects the potentially institutional problem of detail surveying and the limitation of Network-Real Time Kinematic, introduced to measure the cadastral control point first in the issued regulation, and thus presents the improvement and the management of the block boundary of larger parcel as solutions. This can be applied promptly, when the location difference of ground and border, registered in cadastral record for quake and others, occurs. Thus, the public confidence of cadastral record may become higher and relevant social costs get reduced by the advanced prevention effect of boundary dispute, which represents much to the management of cadastral institution. Provided cadastral confirmation surveying is implemented with the management of the block boundary of larger parcel, proposed in this study.

• The KIPS Transactions:PartD
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• v.10D no.3
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• pp.359-366
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• 2003

Although the reuse of the cached data for scrolling the map reduces the amount of passed data between client and server, it needs the conversions of data coordinates, selective deletion of objects, cache compaction and object structuring step in the clients. The conversion is a time- intensive operation due to limited resources of mobile phones such as low computing power, small memory. Therefore, in order to control the map efficiently in the vector map service based mobile phones, it is necessary to study the methods which reuse cached objects for reducing wireless network bandwidth and overwhelming the limited resources of mobile phones as well. This paper proposes the methods of reusing pre-received spatial objects for map control in the mobile vector map service system based on client-server architecture. The experiments conducted on the Web GIS systems with real data show that the proposed method is appropriate to map services for mobile phone. We also analyze the advantages and drawbacks between the reuse of cached data and transmission of raw data respectively.