• Journal of the Korean association of regional geographers
• /
• v.13 no.5
• /
• pp.563-575
• /
• 2007

This study aims to investigate a possibility of using topographic information by web mapping in open environments. Web mapping intends to focus on a map analysis and application of the function and geo-visualization. Functions of Web topographic info-map include a spatial analysis, enlargement and minimization, movement, landuse information, user-controling 3 dimension map, landform cross-section analysis, shortest path analysis. The web system adopts SVG(scalable vector graphics), MYSQL, PHP, XML for mapping. SVG has open source policy, so everyone can use it, as well, it is effective on flexible database linkage, cartographic representation. 3D map is intended to represent 3D map by user-controlled sunshine putting pixel opacity by elevation values after making DEM. Landform is designed to show a cross-section analysis and statistics by retrieving height information from database engine with clicking two points on the map. Shortest path analysis within regions uses Dijkstra's algorithm. Near future, resultantly, the area of WebGIS will have to meet more social demands for use-created geo-information and application, so more researches are needed to be web mapping more applicable for users.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.29 no.2
• /
• pp.141-147
• /
• 2011

This study analyzed the issues and its usefulness of drawing small-scale digital map by using the large-scale digital map which was producted with high-resolution digital aerial photograph which are commonly photographed in recent years. To this end, correlation analysis of the feature categories on the digital map was conducted, and this map was processed by inputting data, organizing, deleting, editing, and supervising feature categories according to the generalization process. As a result, 18 unnecessary feature codes were deleted, and the accuracy of 1/5,000 for the digital map was met. Although the size of the data and the number of feature categories increased, this was proven to be shown due to the excellent description of the digital aerial photograph. Accordingly, it was shown that drawing a small-scale digital map with the large-scale digital map by digital aerial photograph provided excellent description and high-quality information for digital map.

• Spatial Information Research
• /
• v.13 no.1 s.32
• /
• pp.55-63
• /
• 2005

Direct Georeferencing(DG) Is based on the direct measurement of the projection centers and rotation angle of sensor through loading the GPS and INS in aircraft. The methods can offer us to acquire the exterior orientation parameters with only minimum GCPs, even the ground control process could be completely skipped. Hence, as long as securing Digital Elevation Model (DEM), it is feasible to generate digital orthophotos without performing the aerial triangulation with Ground Control Point (GCP) surveying. In this study, the DEM is automatically generated by using a image matching technique based on aerial photos and exterior orientation parameters. This is followed by producing an orthophoto from these results. Finally, accuracy analysis of the georeferencing technique for generating orthoimage indicates that RMS errors of 62cm and 76cm occurred at the X and the Y axis, respectively. This means that the results fulfill the demanding accuracy of the 1:5000 digital map. Hence, it is possible to conclude from this study that the direct georeferencing based orthoimage generation method is able to effectively digital map update.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.10 no.2
• /
• pp.25-30
• /
• 1992

Most algorithms in computer vision and digital photogrammetry assume that digital stereo pairs are registered in epipolar geometry. But, an aerial stereo pair is not likely to be in epiplar geometry since the attitude of the camera at the instant of exposure is different at every exposure station. In this paper, stereo digital imagery is obtained from aerial stereo pair by scanner. Then procesure to resample the digital imagery to epipolar geometry using exterior orientation elements after absolute orientation is described. As a result, a stereo imagery in epipolar geometry is produced from stereo digital imagery. Epipolar imagery in this paper is applied to the image matching method by digital image correlation technique. Then, a digital elevation model is produced from the result of image matching. The digital elevation model in this paper is compared to the other digital elevation model produced by analytical plotter. As a result, an economical method to generate digital elevation model is presented.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.22 no.3
• /
• pp.277-284
• /
• 2004

The subject of this study is to apply experimentally In resolution stereo imagery of IKONOS to producing 1:50,000 scale maps for Munsan area in Paju, being near the Military Demarcation Line, is inaccessible for aerial photography. Ground control points were acquired from GPS surveying to perform geometric corrections on images. Digital maps were produced from IKONOS stereo imagery on the digital photographic workstation. From field investigation, RMS errors of the plane and vertical positions are estimated respectively at $\pm$1.706m and $\pm$1.231m, respectively. These plane and vertical accuracies are within the tolerance limits of those provided in the NGIS Digital Topographic Map Production Rules. Therefore this suggested method is recommended for producing the large scale digital maps of 'No flight' zone near the M.D.L.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.18 no.1
• /
• pp.1-9
• /
• 2000

In the recent day, the necessity and the effective usage are increased rapidly, and it is applied in many other fields as well as in the field of ortho-photo map. In this study, we extract each objects on the aerial image and automatically classify graphic information to produce digital map using only digital ortho-image without particular drawing devices for producing digital map. For this purpose, we have applied a lot of the image processing techniques and fuzzy theory, classified outline and lane of road and building, and had each layer according to each feature. Especially, in the case of the building, the outer vector lines extracted by pixel unit at the building were very complex, but we have developed the program to be expressed by I-dimensional linear type between building corners. In the result of this study, we could not extract and recognize all of the object on the image all together, but we have got the error within 50cm using semi-automatic technique. Therefore, this method will be used effectively in producing 1/5,000 digital map.

• Spatial Information Research
• /
• v.6 no.2
• /
• pp.233-245
• /
• 1998

This study focused on developing a comprehensive strategy to revise 1:1,000 digital topographic maps for Seoul metropolitan area in terms of both organizational and technical aspects. First of all, we analyze the elements of' the revision strategy in the organization domain and produce four alternatives. Of these alternatives, we suggest a best alternative which appears to be practically sound. Secondly, we review four possible map updating methodologies, paper map digitization, a partial topographic map revision method, a method utilizing scanned aerial photographs, and a method using digital orthophotos. Through a detailed technical analysis and cost analysis of each method, we suggest a reasonable map updating method. Finally, we provide a guideline for distributing 1:1,000 digital topographic maps based on the digital map distribution policy National Geography Institute.

• Journal of Korean Society for Geospatial Information Science
• /
• v.13 no.2 s.32
• /
• pp.65-69
• /
• 2005

Efficient 3D generation of cultural features, such as buildings in urban area is becoming increasingly important for a number of GIS applications. For reconstruction or 3D building in urban area aerial images, satellite images, LIDAR data have been used mainly. In case of automatically extracting and reconstructing of building height using single aerial images or single satellite images, there are a lot of problems, such as mismatching that result from a geometric distortion of optical images. Therefore, researches or integrating optical images and existing 2D GIS data(e.g. digital map) has been in progress. In this paper, we focused on extracting of building height by means or interest points and vortical line locus for reducing matching points. Also we used digital plotter in order to validate for the results in this study using aerial images(1/5,000) and existing digital map(1/1,000).

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.12 no.1
• /
• pp.95-103
• /
• 2010

In this paper, a new soft ground tunneling technique termed the PNT method(Pre-Nailed Tunneling Method) is studied. Mechanism of the method is investigated in terms of theoretical and numerical approaches. The pre-nailing effects are validated by performing two dimensional numerical analyses. It is identified that the method is successful in soft grounds, and greatly efficient in reducing the ground deformation by nailing the ground. To develop the design guidelines of the method, numerical parametric analyses on the installation range and angle were also carried out.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.23 no.3
• /
• pp.313-322
• /
• 2005

Rapid advances in technology and changes in human and cultural activities bring about changes to the earth surface in terms of spatial extension as well as time frame of the changes. Such advances introduce shorter updating frequency of maps and geospatial database. To satisfy these requirements, recent research efforts in the geoinformatics field have been focused on the automation and speeding up of the mapping processes which resulted in products such as the digital photogrammetric workstation, GPSIINS, applications of satellite imagery, automatic feature extraction and the LiDAR system. The possibility of automatically extracting buildings and generating contours from airborne LiDAR data has received much attention because LiDAR data produce promising results. However, compared with the manually derived building footprints using traditional photogrammetric process, more investigation and analysis need to be carried out in terms of accuracy and efficiency. On the other hand, generation of the contours with LiDAR data is more efficient and economical in terms of the quality and accuracy. In this study, the effects of various conditions of the pre-processing phase and the subsequent building extraction and contour generation phases for digital mapping have on the accuracy were investigated.