• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.533-540
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• 2006

In recent years, civil-engineering work is desired the terrain information to be more efficient in earthwork volume calculation. One method for collecting elevation data is LiDAR. Lidar data was used to produce rapidly an accurate digital elevation model of the terrain, compared with the conventional ground surveys, photogrammetty, and remote sensing. Raw Lidar data is combined with GPS positional data to georeference the data sets. Lidar data is edited and processed to generate surface models, elevation models, and contours. Here we can either create a Tin Volume Surface or a Gird Volume Surface. Triangulated Irregular Network(TIN) has complex data structure, but it can describe well terrain surface features. As we have seen, we search the efficiency for earthwork volume calculation using Lidar data. One conclusion we can draw from this study is that Lidar data is more accurate result than digital map in the calculation of earthwork volume.

• Korean Journal of Remote Sensing
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• v.17 no.2
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• pp.121-129
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• 2001

A DEM(digital elevation model) is generated from a SPOT panchromatic stereo-pair using automated algorithms over a 8 km$\times$10 km region around Mokpo city. The aims are to continue the accuracy assessment over diverse conditions and to examine the applicability of a SPOT DEM for coastal disaster monitoring. The accuracy is assessed with respect to three reference data sets: 10 global positioning system records, 19 leveling data, and 1:50,000 topography map. The planimetric error is 10.6m r.m.s. and the elevation erroer ranges from 12.4m to 14.4m r.m.s.. The DEM accuracy of the flat Mokpo region is consistent with that over a mountainous area, which supports the robustness of the algorithms. It was found that coordinate transformation errors are significant at a few meters when using the data from leveling and topographic maps. The error budget is greater than the requirements for coastal disaster monitoring. Exploiting that a sub-scene is used, the affine transformation improves the accuracy by 50% during the camera modeling.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.173-178
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• 2004

This paper presents photogrammetric processing to generate digital elevation models and deals with the accuracy potential of SPOT-5 HRG supermode imagery for DEM generation. The DEMs obtained from digital topographic maps of 1/5000 scale were used as the refernce DEM data. DEMs extracted from HRG dats were compared with digital topograpic map DEMs on severed test sections. And digital surface model(DSM), refering to above the ground like buildings, was produced about the test built-up area.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.6
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• pp.131-142
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• 2009

The purpose of this study is to detect the protection area around the Geum-buk and Geum-nam Mountains for making a sustainable ecological network. The protection area in the Geum-buk and Geum-nam Mountains was analyzed by using spatial data and a field survey for landscape conservation purposes. A survey scope was fixed using digital elevation model, and the protection area was finally determined based on the parcel map called as the Korea Land Information System (KLIS). Here we have several conclusions in this study. First, spatial data used in this study were a map of ecological and natural degree (MEND), forest distribution map, elevation map, slope map, and several maps for the protection area assigned by laws regarding to the natural resources. Second, we used 4 alternatives to determine the best choice for showing the ecological network in the study area. One alternative (alt. 3) of 4 ones was finally chosen as the best condition for making the ecological network. The condition in elevation and slope was a little modified to a lower level in alt, 3. The result derived from alt, 3 reflected the continuity and connectivity in the ecological network and we estimate that the protection area can protect the core area using the buffer zone around the ecological network. Finally the parcel-based protection area in the Geum-buk and Geum-nam Mountains had $493.92km^2$ of the core area, and $233.99km^2$ of the buffer zone, which means the parcel-based protection area increased by $97.76km^2$ in the core area, but decreased by $76.61km^2$ as of in the topographical map.

• Journal of Soil and Groundwater Environment
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• v.22 no.6
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• pp.120-128
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• 2017

The aim of this study is to analyze the accuracy of SRTM Ver 3.0 and ASTER GDEM Ver 2 over Korea. To enable this, accuracy analysis was performed by using precise DEM which was made with multiple aerial image matching and national base map benchmark. The result of this study identified both SRTM and ASTER have different features. The height of the SRTM was found to be higher (3.8 m on average) at lower elevation and lower (8.4 m on average) at higher elevation. In contrast, the ASTER was found to be lower than the actual height at both lower and higher elevation (2.92 m, 4.51 m on average). The cause of this height bias according to the elevation is due to the differences in data acquisition and processing methods of DEM. It was identified however that both SRTM and ASTER were within allowable limits of error. In addition, RMSE of the SRTM was smaller than the ASTER in comparison to benchmark, and also the bias trend both at higher and lower terrain were similar to the precise DEM which was made with multiple aerial image matching. Therefore, the reliability of SRTM can be considered to be higher.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.17 no.3
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• pp.293-300
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• 1999

The study aims to develope techniques for generating digital elevation model(DEM) from IRS-1C PAN stereo image data. The bundle adjustment technique was used to determine the satellite exterior orientation parameters as a function of along-track lines. The first degree of polynomial was selected as a function of satellite attitude and position for each scan line. To evaluate the DEM and orthoimage generated, the resulted three dimensional coordinates of the 16 elevation points were computed with the map coordinates. The elevation test showed that root mean square errors of the DEM elevation was about $\pm{16.66m}$ meters.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.6
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• pp.84-99
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• 2021

As the micro-mobility market grows, the demand for route guidance, that includes uphill information as well, is increasing. Since the climbing angle depends on the electric motor uesed, it is necessary to establish an uphill road DB according to the threshold standard. Although road alignment information is a very important element in the basic information of the roads, there is no information currently on the longitudinal slope in the road digital map. The High Definition(HD) map which is being built as a preparation for the era of autonomous vehicles has the altitude value, unlike the existing standard node link system. However, the HD map is very insufficient because it has the altitude value only for some sections of the road network. This paper, hence, intends to propose a method to generate the road longitudinal slope using currently available data. We developed a method of computing the longitudinal slope by combining the digital elevation model and the standard link system. After creating an altitude at the road link point divided by 4m based on the Seoul road network, we calculated individual slope per unit distance of the road. After designating a representative slope for each road link, we have extracted the very steep road that cannot be climbed with personal mobility and the slippery roads that cannot be used during heavy snowfall. We additionally described errors in the altitude values due to surrounding terrain and the issues related to the slope calculation method. In the future, we expect that the road longitudinal slope information will be used as basic data that can be used for various convergence analyses.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.14-17
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• 2008

KOMPSAT-2 is the seventh high-resolution satellite in the world that provides both 1m panchromatic images and 4m multispectral images of the GSD. It is expected to be used across many different fields including digital mapping, territorial and environmental monitoring. However, due to the complexity and security concern involved with the use of the MSC, the use of KOMPSAT-2 images are limited in terms of geometric data, such as satellite orbits and detailed mapping information. This study aims to generate the DEM and orthoimage by using the stereo images of KOMPSAT-2 and to explore the applicability of geo-spatial information with KOMPSAT-2. In order to ensure generation of DEMs of optimal accuracy, the RPCs data and a suitable number of GCPs were used. The accuracy of DEM generated in this research compared with DEM generated from 1:5,000 digital map. The mean differences between horizontal position of the orthoimage and the digital map data are found to be ${\pm}$3.1m, which is in the range of ${\pm}$3.5m, within the permitted limit of a 1:5,000 digital map. The results suggest that DEM can be adequately used to produce digital maps under 1:5,000 scale.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.16 no.1
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• pp.119-132
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• 1998

For the purpose of producing of grid D.E.M based on National Digital Map accurately and efficiently, We must carefully consider arrangement and numbers of it's elevation information, supplement interpolation method of control point information for maintaining accuracy. According to each combination, each of them has an effect on estimate elevations. This study, after finishing experimental analysis of several grid distance and interpolation methods, aims at presenting the optimal grid distance and interpolation method in the production of grid D.E.M by using of National Digital Map. The results are as follows: First, The result of experimental analysis shows that the method of Kriging is a very excellent interpolation method in the production of grid D.E. M by using National Digital Map. Second, For the purpose of determining grid distance, this study present that twice of the amount of contour interval to make producing grid D.E.M is optimal distance.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.217-222
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• 2006

In this study, we performed three dimensional(3-D) modeling and simulation of terrain surfaces by using large scale aerial photographs. The objectives of this study are to use landscape analysis including 3-D database of built environments. The test area is selected around Olympic stadium located in Susung-gu, Daegu. A 1:5,000 scale of ortho-photo map is generated by photogrammetric procedures from 1:20,000 scale of aerial photographs, Digital Elevation Model (DEM) is also extracted from stereo aerial photographs or digital maps. The heights of buildings are determined using GPS control survey and aerial photographs in the test area, DEMs are extracted from the digital map. And then the two are combined three-dimensional changes of landscape views of buildings with terrain are simulated.