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Building National Spitial Imagery Database

Building National Spitial Imagery Database
  • NGII Plan
  • Building National Spatial Imagenery Database
  • Establishment of National Spatial Data Infrastructure
  • Production and dissemination of national map
Spatial Images
Collecting aerial photographs and building a database
Overview
To obtain an aerial image, a plane equipped with an aerial surveying camera flies at a constant altitude and captures photographs of the land, overlapping 60% horizontally and 30% vertically, projecting geographic and natural features on the surface of land.
In 2010, digital color aerial images replaced analog photography.
  • Analog Analog
  • Digital Digital
Aerial images are mainly used for producing maps, but they are also valuable data for detecting any changes in the condition of national territory, as well as for historical reference. The NGII is archiving a large quantity of aerial images, which can be issued upon application with the exception of images of security areas.
Related regulations
Regulations for Surveying Aerial Images (National Geographic Information Institute Announcement No. 2009-948; December 14, 2009)
Timeline
Surveying aerial images
1966-1974: Took aerial photographs at the scale of 1/37000
*August 1966: Agreement on Korea-Japan Joint Surveying of Aerial Images
1974-1995: Took aerial photographs at the scales of 1/37000 and 1/20000
1995-2006: Took aerial photographs at the scales of 1/5000, 1/10000, and 1/20000
2007-2009: Took aerial photographs at the scale of 1/20000 every four years
2010: Complete replacement of analog aerial images with digital color photographs
Establishment and services of the spatial image information database
2000-2004: Establishment of research projects and a 40,000-strong database of aerial images
2004-2005: Development of an online service system
September 2005: Launch of the online service system
April 2010: Launch of integrated service for aerial images and satellite images (http://air.ngii.go.kr)
Database status
Database status
Grand total 308,664 125,900    
Year Scale Photographed area No. of images Target area Remark
1999-2004   91,100 19,314    
2005 1/20000 16,000 3,371 Gangwon-do Analog mode
  1/20000 11,000 337  
2006 1/20000 6,000 1,614 Seoul Metropolitan Area
  1/20000 8,000 1,504  
  1/20000 4,200 978  
2007 1/20000 8,000 2,240 Chungcheong-do
  1/20000 6,520 1,611  
  1/20000 7,800 1,765 Jeollabuk-do
2008 1/20000 8,400 2,196 Jeollanam-do
  1/20000 7,900 1,876  
  1/20000 8,112 2,307 Gyeongsang-do
2009 1/20000 11,875 2,933 Taebaek
  1/20000 12,500 3,112 Pohang
  GSD25cm 7,182 3,086 Sokcho Digital mode
2010 GSD25cm 94,075 77,656 Nationwide Digital mode
(Unit: km², sheet)
Digital Elevation Model and Orthophotomap
Overview
Digital elevation model (DEM) is a term referring to a three-dimensional model that represents the outline of actual topographic land surface features in the form of dots and lines. It uses images or mathematical models to represent topography or objects. It first retrieves random three-dimensional coordinates from a target area and displays the highs and lows of the land surface in a geometric fashion, enabling the numerical interpretation of topographical features. Research into the theory and application of the DEM was pioneered in America in 1958 by C. L. Miller when he applied the DEM to alternative route assessment and earth-volume calculation in designing roads. In the 1960s, DEM programs were developed based on different kinds of interpolation and, from around 1970, began to be used for developing housing sites and planning and designing routes and dams. For orthophotomaps, topographic outlines are revised through the use of information from aerial images combined with a digital elevation model.
* Written maps (Papers and figures) » Photographic maps (Aerial images and satellite orthophotomaps)
Conversion of a digital elevation model and orthophotomaps
  • Conversion of a digital elevation model and orthophotomaps
Related regulations
Regulations for Preparing Digital Maps (National Geographic Information Institute Announcement No. 2009-946; December 14, 2009)
Regulations for Surveying Aerial Images (National Geographic Information Institute Announcement No. 2009-948; December 14, 2009)
Regulations for Producing Image Maps (National Geographic Information Institute Announcement No. 2009-949; December 14, 2009)
Regulations for Airborne Laser Surveying (National Geographic Information Institute Announcement No. 2009-950; December 14, 2009)
Timeline
2000: Research on Production of Topographic Data by Airborne Laser Surveying
2002: Produced a digital elevation model of five-meter grids in Seoul and Suwon by using airborne laser surveying
December 2002: Established Regulations for Building Digital Elevation Database
2003: Produced a digital elevation model of 10-meter grids for the entire country
* Excluding islands and coastal areas
2005: Established the Basic Plan for Building Multi-dimensional Spatial Information, which combines a digital elevation model with orthophotographs
2006-2008: Launched projects in 29 cities, including Jeju
January 2009: Established the Regulations for Airborne Laser Surveying
2009: Launched projects in 16 cities, including Seoul
2010: Launched a project in Chungju
Database status
Database status
Grand total 23,274      
Year Project area Area Digital Elevation Orthophoto
    Method Grid Scale
2006 Jeju, Ulsan, Wonju, Uiwang, Yangsan, Tongyeong, and Jinhae 4,650 LiDAR 1, 5 1/5000
2007 Busan, Gwangju, Gunsan, Incheon, Cheongju, Suwon, Daegu, and Osan 3,235 LiDAR 1 1/5000
2008 Guri, Uijeongbu, Masan, and Changwon 736 LiDAR 1 1/5000
  Jangseong-gun 520 LiDAR 1 1/5000
2009 Gongju and Gwangyang 1,437 LiDAR 1 1/5000
  Bucheon, Siheung, Ansan, Gwacheon, Gwangmyeong, Gunpo, Anyang, and Hanam 621 LiDAR 1 1/5000
  Gapyeong-gun and Yangpyeong-gun 1,721 LiDAR 1 1/5000
  Hwaseong and Pyeongtaek 1,141 LiDAR 1 1/5000
  Anseong and Icheon 1,014 LiDAR 1 1/5000
  Goyang and Namyangju 725 LiDAR 1 1/5000
  Chuncheon 1,116 LiDAR 1 1/5000
  Yeosu 501 LiDAR 1 1/5000
  Seoul 605 LiDAR 1 1/5000
  Yongin and Yeoju 1,199 LiDAR 1 1/5000
  Jecheon 882 LiDAR 1 1/5000
  Yeongam-gun 601 LiDAR 1 1/5000
  Hoengseong-gun 840 LiDAR 1 1/5000
  Yeongdeok-gun 746 LiDAR 1 1/5000
2010 Chungju 984 LiDAR 1 -
*Completion of constructing a digital elevation model of 10-meter grids for the entire country in 2003 (Unit: km², sheet)
National Land Monitoring Project
Overview
The National Land Monitoring Project gathers assorted spatial data (aerial images, satellite images, digital maps, etc.), compares and analyzes them, and classifies topographic features into six categories by 1/5000 map sheet and uncovers information on any changes.
Six categories of topographic classification
Six categories of topographic classification
Urban area Areas in which street networks are formed and communities, factories, houses, apartments, and other structures are concentrated
Suburban area Areas in which factories, houses, apartments, and other structures are fairly densely located
Agricultural area Areas in which agricultural produce is cultivated and plant clusters (rice paddies, fields, orchards, etc.) are located
Hilly area Areas in which agricultural produce is not cultivated, or undeveloped areas without forests with a gradient of less than five degrees
Mountainous area Areas around forests (conifers and broad-leaved trees)
Water system Areas around seas, rivers, or reservoirs
Procedure of the National Land Monitoring Project
  • Obtaining images->Producing orthophotographs->Classifying topography->Computing information on changes
Procedure of the National Land Monitoring Project
Producing orthophotomaps To produce an orthophotomap by converting images from satellites or airborne sensors into more accurate forms such as a map
Classifying topography To classify and calculate the size of topographic features based on major categories (urban areas, suburban areas, agricultural areas, hilly areas, mountainous areas, water systems, roads) based on digital maps and satellite images
Computing information on changes To detect and calculate the size of any topographic changes to a certain area by using data from different time periods
Timeline
2005: Pilot project for national land monitoring (Gangwon-do area)
2006: Pilot project for Seoul Metropolitan Area (north and south districts) (including scholarly research)
2007-2009: Chungcheong-do and Jeollabuk-do areas, Gyeongsang-do and Jeollanam-do areas, and Gangwon-do and Gyeongsangbuk-do areas
Database status
Database status
Grand total 120,125
Year Project area Number of projects Images in use
2004 Gangwon-do 23,220 Spot, OrbView 3
2005 Seoul Metropolitan Area (north district) 11,780 Spot
2006 Seoul Metropolitan Area (south district) 6,836 Spot
2007 Chungcheong-do and Jeollabuk-do 22,320 Spot
2008 Gyeongsang-do and Jeollanam-do 24,412 Spot
2009 Gangwon-do and Gyeongsangbuk-do 31,557 Spot
(Unit: km²)