• Title/Summary/Keyword: SurveyingMap system

Search Result 294, Processing Time 0.022 seconds

Generation of Building and Contour Layers for Digital Mapping Using LiDAR Data (LiDAR 데이터를 이용한 수치지도의 건물 및 등고선 레이어 생성)

  • Lee Dong-Cheon;Yom Jae-Hong
    • 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.

3D Building Reconstruction and Visualization by Clustering Airborne LiDAR Data and Roof Shape Analysis

  • Lee, Dong-Cheon;Jung, Hyung-Sup;Yom, Jae-Hong
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
    • /
    • v.25 no.6_1
    • /
    • pp.507-516
    • /
    • 2007
  • Segmentation and organization of the LiDAR (Light Detection and Ranging) data of the Earth's surface are difficult tasks because the captured LiDAR data are composed of irregularly distributed point clouds with lack of semantic information. The reason for this difficulty in processing LiDAR data is that the data provide huge amount of the spatial coordinates without topological and/or relational information among the points. This study introduces LiDAR data segmentation technique by utilizing histograms of the LiDAR height image data and analyzing roof shape for 3D reconstruction and visualization of the buildings. One of the advantages in utilizing LiDAR height image data is no registration required because the LiDAR data are geo-referenced and ortho-projected data. In consequence, measurements on the image provide absolute reference coordinates. The LiDAR image allows measurement of the initial building boundaries to estimate locations of the side walls and to form the planar surfaces which represent approximate building footprints. LiDAR points close to each side wall were grouped together then the least-square planar surface fitting with the segmented point clouds was performed to determine precise location of each wall of an building. Finally, roof shape analysis was performed by accumulated slopes along the profiles of the roof top. However, simulated LiDAR data were used for analyzing roof shape because buildings with various shapes of the roof do not exist in the test area. The proposed approach has been tested on the heavily built-up urban residential area. 3D digital vector map produced by digitizing complied aerial photographs was used to evaluate accuracy of the results. Experimental results show efficiency of the proposed methodology for 3D building reconstruction and large scale digital mapping especially for the urban area.

Thematic Map Construction of Erosion and Deposition in Rivers Using GIS-based DEM Comparison Technique

  • Han, Seung Hee
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
    • /
    • v.34 no.2
    • /
    • pp.153-159
    • /
    • 2016
  • Rivers refer to either natural or artificial structures whose primary functions are flood control and water conservation. Due to recent localized torrential downpours led by climate change, large amounts of eroded soil have been carried away, forming deposits downstream, which in turn degrades the capacity to fulfill these functions. To manage rivers more effectively, we need data on riverbed erosion and deposition. However, environmental factors make it challenging to take measurements in rivers, and data errors tend to prevent researchers from grasping the current state of erosions and deposits. In this context, the aim of the present study is to provide basic data required for river management. To this end, the author made annual measurements with a Real-time Kinematic-Global Positioning System (RTK-GPS) and a total station in Pats Cabin Canyon, Oregon, United States, and also prepared thematic maps of erosion and deposition thickness as well as water depth profiles based on a GIS spatial analysis. Furthermore, the author statistically analyzed the accuracy of three dimensional (3D) measurement points and only used the data that falls within two standard deviations (i.e. ±2σ). In addition, the author determined a threshold for a DEM of Difference (DoD) by installing measurement points in the rivers and taking measurements, and then estimated erosion and deposition thickness within a confidence interval of ±0.1m. Based on the results, the author established reliable data on river depth profiles and thematic maps of erosion and deposition thickness using pre-determined work flows. It is anticipated that the riverbed data can be utilized for effective river management.

Shadow Extraction of Urban Area using Building Edge Buffer in Quickbird Image (건물 에지 버퍼를 이용한 Quickbird 영상의 도심지 그림자 추출)

  • Yeom, Jun-Ho;Chang, An-Jin;Kim, Yong-Il
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
    • /
    • v.30 no.2
    • /
    • pp.163-171
    • /
    • 2012
  • High resolution satellite images have been used for building and road system analysis, landscape analysis, and ecological assessment for several years. However, in high resolution satellite images, shadows are necessarily cast by manmade objects such as buildings and over-pass bridges. This paper develops the shadow extraction procedures in urban area including various land-use classes, and the extracted shadow areas are evaluated by a manually digitized shadow map. For the shadow extraction, the Canny edge operator and the dilation filter are applied to make building edge buffer area. Also, the object-based segmentation was performed using Gram-Schmitt fusion image, and spectral and spatial parameters are calculated from the segmentation results. Finally, we proposed appropriate parameters and extraction rules for the shadow extraction. The accuracy of the shadow extraction results from the various assessment indices is 80% to 90%.

Construction and Application of 3D Image Model for GIS Spatial Analysis (GIS 공간분석을 위한 3D 영상모형의 구축과 활용)

  • Jung, Sung-Heuk;Lee, Kae-Dong;Lee, Jae-Kee
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
    • /
    • v.26 no.6
    • /
    • pp.561-569
    • /
    • 2008
  • Currently, satellite image, aerial image and airborne laser scanning data are mostly used to build 3D image models. However, we are in need of quality 3D image models as current models cannot express topographic and features most elaborately and realistically. When making 3D image models, the model is first built and textures from terrestrial photos are applied to add realistic features to the model. This study analyzed techniques to use photogrammetry and laser scanning data to create a 3D image models with topography, building and statue that emphasize spatial accuracy, delicate depiction and photo-realistic imaging. 3D image models with spatial accuracy and photographic texture were built to be served via 3D image map services systems on the internet. The 3D image models can be used for various purposes, such as daylight and view right analysis, landscape analysis, facility management system.

The Study on Coordinate Transformation for Updating of Digital Map from Construction Drawing Data (건설도면 자료의 수치지도 갱신을 위한 좌표체계 부여에 관한 연구)

  • Park, Seung-Yong;Lee, Jae-Bin;Park, Woo-Jin;Yu, Ki-Yun
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
    • /
    • v.27 no.2
    • /
    • pp.281-288
    • /
    • 2009
  • In the paper, we try to develop the methodology for updating road networks of large-scale digital maps by using construction drawing data. For the purpose, it is pre-requite step to merge road networks detached in CAD drawing data. As such, tie points are identified in neighboring drawings and used for solving the parameters of 2D conformal transformation between drawings. Then, the merged road network in CAD data is transformed to the coordinate system of digital maps. In the process, IPs in the drawings are considered as control information and 2D affine transformation is selected for coordinate transformation. Through the experiments with real dataset, we can identify that the developed method is valid and generally applicable.

A Study on The Marine Geographical Framework Data in Korea (해양기본지리정보 구축에 관한 기초연구)

  • 최윤수;오순복;박병문;김정현;서상현
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
    • /
    • v.20 no.3
    • /
    • pp.293-301
    • /
    • 2002
  • MGF(Marine Geographical Framework) data are the essential data sets concerning graphical and attribute information on coast and ocean among various marine-related data, which consist of framework data of the National Spatial Data Infrastructure(NSDI). This study did research and analyzed the development of current data, the situation of its usage, related technical environment and case study of foreign countries through the survey on the users and experts. Then the item of marine geographical framework data was selected in accordance with the measures for usage and management of possible MGF data. A map was pilot producted based on selected items and MGF data was presented through making up some problems shown ill the process. The importance of GIS will be growing continuously which can develop, deal with and provide the various data to efficiently manage coast and ocean. Accordingly, the MGF data will be applied to various areas such as Internet or raw data for marine information system.

Establishment of the Plane Coordinate System for Framework Data(UTM-K) in Korea (우리나라 기본지리정보 좌표계(UTM-K) 도입에 관한 연구)

  • Choi, Yun Soo;Kim Gun Soo;Park Hong Gi
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
    • /
    • v.22 no.4
    • /
    • pp.313-321
    • /
    • 2004
  • Korean government has offcially decided to adopt global geodetic reference system(ITRF and GRS80) from 2007 keeping pace with the spread of GNSS. Industries related with LBS and telematics have called for use of the new coordinate system suitable for GIS/GPS applications. The government also defined the single plane coordinate system that covers entire korean peninsula as UTM-K considering DB-based framework data and user-friendliness, and its defects were corrected while being applied to the building of road framework data. The TM projection, and origin scale factor of plane coordinate system, 0.9996were employed in order to satisfy the single plane coordinate system for the entire Korean peninsula. For the origin of plane coordinate system, longitude of $127^{\circ}$30'00" and latitude of $38^{\circ}$00'00" were applied and, for the initial value of plane coordinate system, N=2,000.000m and E=1,000,000m were used. In addition to considerable savings in costs, it is expected that the UTM-K is applicable for correcting errors occurred during acquisition of geographic information and for aggregating map data produced by different sources. However, during the initial stage for introduction, confusion is forecasted due to the use of two different coordinate systems, which may be minimized by continued publicity and education.

A Study of GPS Ship Navigation System Using Precise Coordinate Conversion Algorithms. (정밀 좌표변환 알고리즘을 이용한 인공위성 항로추적시스템에 관한 연구)

  • Chang, Yong-Ku;Mun, Du-Yeoul;Choi, Sung-Jae;Lee, Young-Hee
    • Journal of Navigation and Port Research
    • /
    • v.27 no.1
    • /
    • pp.41-48
    • /
    • 2003
  • The most great GPS is working on CNS(Car navigation System) and Personal terminal, but ocean has not been. First studied GPS is sailing to ship but We have been connivance that The ship is not need detail navigation. Lately, harbor facilities and transportation service in harbors are complication. We have need accurate ship navigation system. In this paper, author developed algorithms of ellipsoid conversion between WGS84 and BESSEL and develope algorithms of map projection between ellipsoid coordinate system, and plane cartesian system. Author used 3-parameter in covering ellipsoids and used TM and UTM projection in converting between ellipsoid and plane cartesian coordinate. And author analyzed errors through static surveying and dynamic surveying of GPS for proving accuracy of GPS sensor, Furthermore author analyzed deflection error of received position. Finally author developed real time ship navigation system using cheep GPS sensor.

Analysis on Pilot Survey for Cadastral Non-correspondence Arrangements (지적불부합지의 정리를 위한 실험측량 분석 연구)

  • 강태석;권규태
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
    • /
    • v.21 no.3
    • /
    • pp.269-275
    • /
    • 2003
  • The cadastral system which accomplishes the base of national land administration with accuracy of proper data and the cadastral maintenance quickly is agreeing with the actual place in information ages in Inundation. But even in spite of many efforts, various Problems are exposed in accuracy of the data on the cadastral maps and local situation must agree accurately from the process which propels cadastral information systems. Therefore, it must be carried out the cadastral non correspondence arrangement first of all in link of the plan which it corrects the error of existing data and computerization quickly. It summarizes the research as follows ; Cadastral non correspondence of the land boundaries on the map and actual circumstance does not agree with cadastral maps accurately, The lands which exceed the standards with the position error excess of 50cm on lil ,200 and 240cm on 1/6,000 areas on the map scale are the registration correction objectives. It is investigated that the cadastral non correspondence parcels occur in various cause and long period, the area error corrections are mainly objectives, and about 80% of the test area comes to reveal within permitted the limit of the measurement of planimetric area for cadastral survey, so it is not difficult with the fact that the compensation back which it follows in area increase and decrease and the location error correction becomes the important object fer the cadastral non correspondence arrangement projects.