• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.19 no.4
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• pp.327-335
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• 2001

This paper present to how to make VGIS(Virtual Geographic Information System) using GIS and digital map. Because the development of the GIS has been 2-dimension in the last few years, viewpoint of the high-resolution image estimate was difficult. The geo-spatial information system has lots of errors in the policy decision and the principal decision making because it was displayed as 2 dimension map that the digital map and topographical map, geological map. agronomical map, cadastral map and underground facility map are expressed as a symbol practically in spite that it is spatial topography data. It is utilized as effective administration analyzing, all kinds of discussion, transportation and environmental effect evaluation, various kinds of building discussion and policy decision thorough researching the present condition of region as 3 dimension map using digital map and GIS when drafting and deciding all kinds of urban plaining so it is considered that errors of policy decision will be minimized.

• The Journal of the Korea Contents Association
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• v.7 no.3
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• pp.168-175
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• 2007

The flood caused landslide disaster each year because of climate change. And the change of topography from an earthquake makes topographical analysis impossible. This paper performed an investigation about a utilization methods and generation DEM(Digital Elevation Model) after digital aerial photographs quickly when the topographical change happens. Stereo imagery that was collected through digital aerial photographs made a generation of DEM possible. A standard deviation of generated DEM is 0.864m which is somewhat high but shows the real topography. As a result, it should be possible to generate DEM by using aerial photographs in case of the change of topography.

• Spatial Information Research
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• v.10 no.3
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• pp.469-480
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• 2002

Nowadays, digital maps of 1:5,000 scale are used to plan and review far road alignment design. However, the updating and modifying period of digital maps is not so harmonious as topographical changes caused by rapid developments can be reflected in digital maps, the different areas between real surface and digital map can be found easily. This research is aimed to suggest that the use of high resolution satellite image is effective way to get latest topographical information for road alignment design about wide region. IKONOS satellite images were geometrically corrected, and the road alignment data previously designed by traditional procedure were overlapped on the satellite images. As a result, the satellite image maps clearly described wrong road alignment, and modification of road alignment could be accomplished adequately By these procedures, road alignment design was Improved in quality, and could be reasonable and economic design to prevent modification that would be happened in the next step of practical plan. For the geometric correction method of IKONOS images, Thin Plate Spline(TPS) transformation with large number of ground control points, as well as ortho rectification, was effective.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.35 no.6
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• pp.517-526
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• 2017

In this study, we analyzed the accuracy of elevation, slope, and area to the damage scale of the debris flow using the drones to track the details of the debris flow that method was between the digital topographical map(1/5,000) method and GPS ground survey method. The results are summarized as follows. At first, in the comparison of elevation, the value by the drones was 3.024m lower than the digital topography map, but in case of slope the average slope was $1.20^{\circ}$ and the maximum slope was $10.46^{\circ}$ which was higher by the drones image. Secondly, the difference area is $462m^2$ between on the digital topographic map and the drones image was calculated high, because it is determined by reflecting the uplift of the terrain as a point that calculated more accurate than the digital topographic map. Therefore, when compared with the existing method, the drone image method was very effective in terms of time and manpower.

• Journal of Korea Spatial Information System Society
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• v.3 no.2 s.6
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• pp.5-19
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• 2001

We are able to construct and utilize DEM(Digital Elevation Model) throughout the NGIS(National Geographic Information System) project. It is important that interpolation methods and appreciate size of grid for the construction of accurate DEM(Digital Elevation Model). There were several references related to the DEM(Digital Elevation Model) construction method, however they couldn't consider various topographical characteristics in the korea. In this study, we recommended that suitable interpolation method for each topographic element. After dividing Poonggi area into mountain, hill, urban, agricultural land, we constructed DEM(Digital Elevation Model) with various interpolation methods and grid size using 1:5,000 digital map. Then evaluated accuracy using elevation data which extracted from air-photo. The interpolation methods were analyzed and compared for various topographical conditions. As a result, Kriging method was superior to TIN method for all the topographical conditions. Another experiment was performed to examine optimal grid space for DEM with each topographical condition. 10m grid space was most suitable for mountain area and hilly districts, while 30m grid space was most suitable for urban area and farm land.

• Korean Journal of Remote Sensing
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• v.34 no.6_3
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• pp.1329-1350
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• 2018

There have been many applications to observe Earth using synthetic aperture radar (SAR) since it could acquire Earth observation data without reference to weathers or local times. However researches about digital map generation using SAR have hardly been performed due to complex raw data processing. In this study, we suggested feasibility of producing digital map using SAR stereo images. We collected two sets, which include an ascending and a descending orbit acquisitions respectively, of KOMPSAT-5 stereo dataset. In order to suggest the feasibility of digital map generation from SAR stereo images, we performed 1) rational polynomial coefficient transformation from radar geometry, 2) digital resititution using KOMPSAT-5 stereo images, and 3) validation using digital-map-derived reference points and check points. As the results of two models, root mean squared errors of XY and Z direction were less than 1m for each model. We discussed that KOMPSAT-5 stereo image could generated 1:25,000 digital map which meets a standard of the digital map. The proposed results would contribute to generate and update digital maps for inaccessible areas and wherever weather conditions are unstable such as North Korea or Polar region.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.893-903
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• 2008

A method for predicting surface failures which occur during heavy rainfall on mountain slopes is proposed by using the digital land form model that is obtained by reading altitude on a topographical map at 10m grid point space. A depth of a potential failure layer is assumed at each grid point. In the layer, an infiltrated water movement from cell to cell is modeled in the study (cell is a square of the grid). Infiltrated ground water levels which show the three dimensional effects of a topographical factor in an area can be hourly calculated at every cell by the model. The safety factor of every cell is also calculated every hour by the infinite slope stability analysis method with the obtained infiltrated ground water level. Failure potential delineation is defined here as the time when the safety factor becomes less than unity under the assumptions that effective rainfall is 20mm/h and continues 20 hours.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1424-1426
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• 2003

It will be a real good news for the people who were lost their hometown by the construction of a large dam to be restored to the former state. Focused on Cheung-Pyung around where most part were flooded by the Chungju large Dam founded in early 1980s, we used Remote Sensing Technique in this study in order to restore topographical features before the flood with 3 dimensional effects. We gathered comparatively good satellite photos and remotely sensed digital images, then we made a new color image from these and the topographical map which had been made before the flood. This task was putting together two kinds of different timed images. And then, we generated DEM including the outskirts of that area as harmonizing current contour lines with the map. That could be a perfect 3D image of Cheung-Pyung around before when it had been flood by making perspective images from all directions, north, south, east and west, for showing there in three dimensions. Also, flying simulation we made for close visiting can bring us to experience their real space at that time.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.1 s.19
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• pp.91-100
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• 2002

Recently, many studies on the construction of management system for road facility have been accomplished, and in its process the digital map is used as the essential data for spatial database. But in case where the existing topographical map or completion map of construction data is not sufficient for Data Base construction, the compilation, modification or renewal of digital map should be conflicted with large obstacles. This study intended to extract the road facility information using the image data of various form such as aerial photographs, terrestrial photographs and so on. The terrestrial photographic images are taken by hand-held camera, digital camera and video camera which are widely used and of low price in general. This study used the single frame images only for the raw image data, and the extracted spatial and attribute data from the images are used for modifying and updating the database. In addition, the creating possibility of the digital map in the relative scale using the spatial data extracted from the single images was tried.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2007.04a
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• pp.257-260
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• 2007

The government is spending a large amount of budget to establish NGIS due to the importance of geospatial information. This paper deals with the study of schema mapping technique which can efficiently establish military topographic DB forest layer using digital forest map and other existing geospatial DB. In order to accomplish this 1) each schema of these types of DB was analyzed then, 2) mapping table which connects related attributes was created and finally, 3) military topographical DB forest layer of the area of interest was efficiently established. This research was able to display solutions that resolved compatibility issues between existing geospatial DB of these types, established by the schema mapping techniques described in this research.