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НОВЫЕ ТЕХНОЛОГИИ И ИХ ПЕРСПЕКТИВЫ ДЛЯ ГЕОИНФОРМАТИКИ
Готтфрид Конечный
Ганноверский университет им. Лейбница, Nienburger Str.1, D-30167 Ганновер, Германия, засл. профессор, почетный профессор СГГА, тел/факс: 0049-511-762-2483, e-mail:
konecny@ipi.uni-hannover. de
Прогресс геоинформационной технологии зависит от новых технологий, появляющихся в ходе научно-технических разработок. Они открывают новые возможности для дисциплины целым рядом применений:
- ГНСС позиционирование
- Цифровое изображение
- Спутниковое изображение
- Обработка стерео изображения
- Радарное и лазерное сканирование
- Достижения компьютерной технологии
- Технология баз данных
- Веб-приложения
- Технология мобильной связи
Эти применения делают геоинформатику более эффективной и позволяют решать те задачи, которые раньше невозможно было решать.
Ключевые слова: геодезическая технология, техническое новшество, позиционирование, аэрокосмическое изображение, лазеры, закон Мура, базы данных, веб-приложения, мобильная связь.
TECHNOLOGY INNOVATIONS AND THEIR CHALLENGES FOR GEOINFORMATICS
Gottfried Konecny
Leibniz University Hannover, Institute for Photogrammetry and Geoinformation, Nienburger Str.1, D-30167 Hannover, Germany, Emeritus Professor, Honorary Professor of SSGA, office/fax: 0049511-762-2483, e-mail: konecny@ipi.uni-hannover.de
Progress in geoinformatics technology depends on technological innovations introduced by other scientific and engineering developments. These offer challenges to the discipline in a variety of applications, such as:
- GNSS positioning satellites
- Digital imaging
- Satellite imaging
- Stereo image processing
- Radar and laser scanning
- Omputer technology advances
- Data base technology
- Web applications
- Mobile communication technology
These applications make geoinformatics more efficient and they help to complete tasks previously not possible to undertake.
Key words: surveying technology, technical innovation, positioning, aerial imaging, satellite imaging, lasers, Moore's Law, data bases, web applications, mobile communication.
1. Introduction
The Surveying and Mapping disciplines are an applied technology. From the very beginning they have used inventions of science and technology for the purpose of measuring and describing the earth's surface and their objects. Survey instruments, such as the theodolite were not created by surveyors, but by mechanical craftsmen and optical scientists, and photogrammetry would not have come about without the invention of photography and of aerial platforms.
Willem Schermerhorn, Prime Minister of the Netherlands after 1945 and founder of the ITC, which brought photogrammetry to the developing world, said at the 50th Anniversary of the German Society for photogrammetry in 1959: “None of the designers in photogrammetry were survey specialists. They either came to photogrammetry from aviation or as engineers and physicists”.
At the 100th Anniversary of the International Society for Photogrammetry and remote Sensing in Vienna in 2010 the economist Franz Radermacher said: “We all stand on the shoulders of giants, who make our progress possible”.
This is a good reason to make a review of the technological innovations of today, which offer challenges to geoinformatics by their application.
One of the economists trying to establish a link between technological innovation and the economy was Nikolai Dmitrijevich Kondratjev (1892-1938). He stated, that a paradigm change takes place in society every 40 to 60 years, which leads to sudden improvements in technology and its economic consequences. Kondratjev and his followers identified five Kondratjev cycles since the beginning of industrialization around 1780:
- Mechanical weaving, steam ships, coal and iron technology (1780-1850 power)
- Railways, the telegraph, cement, photography (1850-1890 transport)
- Electrification, chemistry, the automobile, aluminum (1890-1940 flight)
- Electronics, television, nuclear power, space technology (1940-1990 automation)
- Information technology, the Internet (1990-2040 communication).
In this context it is interesting to compare, which technologies made available by others are being adapted to geoinformation tasks.
2. Current Technology Innovations with impact on geoinformatics
These techniques are:
- GPS-GNSS geopositioning
- Digital aerial photography
- Satellite imaging covering the globe
- Stereo image processing software
- Radar and laser scanning
- Computer technology advances
- Data base technology
- Web applications
- Mobile communication technology.
GNSS-GPS satellite positioning
The GNSS positioning technology permits to determine a geometrical figure of the earth with precise coordinates. Combined with gravity observations the physical figure of the earth may be precisely determined. Extending these observations into a time series, earth rotation and crustal motion may be monitored with high precision, fulfilling the scientific tasks of geodesy.
At the technical level GNSS-GPS permits to create a 3 dimensional terrestrial reference frame. For this purpose the International GNSS Service (IGS) has been established. It is a voluntary service monitoring GPS and GLONASS performance from more than 200 stations distributed over the globe. This permits to create a global framework for high accuracy geocoding of measurement stations. In this manner fiducial stations for continuous observations for each continent (EUREF, SIRGAS) or each country (SAPOS, SWEPOS) may be established. By these it becomes possible to correct the distance dependent systematic signal errors, which are mainly caused by the ionosphere. With a sufficient density of reference stations (CORS), e.g. every 50 km, positioning with 1cm precision may be obtained (and with 10 km spacing a precision of several mm is possible).
It is of interest, that GNSS positioning with 10cm precision is also dynamically possible in aircraft and other moving platforms.
These high accuracies are of course only attainable with rather expensive GNSS phase receivers costing several 10 000$, while the inexpensive code receivers costing no more than several 100$ only yield 10m relative accuracy positions.
Nevertheless, augmented accuracy communication satellite systems, such as EGNOS, WAAS and Omnistar may be used in some parts or all over the globe to permit positioning with simple receivers to precisions in the range of several dm to about 5 m.
This makes older methods of positioning, such as triangulation or traversing irrelevant, unless reception of GNSS signals is inhibited due to high buildings, trees or power lines. In that case GNSS receivers must be used in combination with total stations.
Digital Aerial Imagery
The era of aerial photography on film, initiated during World War I in 1915 has ended. Kodak and Agfa have stopped to deliver new aerial films. Digital cameras were first introduced in the consumer market, but specialized high resolution systems followed. Aerial frame cameras with CCD arrays extended over limited areas became introduced by Intergraph-Zeiss Imaging with the DMC camera or by Microsoft-Vexcel with the Ultracam camera series. In competition to the frame cameras, CCD line scan cameras have been introduced by Leica with the ADS40 and ADS80 scanners, which had proved successful from space before. Now that both Leica and
Intergraph are part of Hexagon, the competition has stopped. Line scanners have probed to be more beneficial for large area orthophoto generation, while aerial frame cameras are preferred for photogrammetric digital line mapping.
In addition to the cameras mentioned, a great number of other manufacturers have provided digital cameras with somewhat less performance. This performance, however, is still far better than that of old film cameras, as independent comparative tests have shown (e.g. by the German Society for Photogrammetry, Remote Sensing and Geoinformation).
Several of these cameras can also be combined for vertical and oblique uses (e.g. Pictometry) applicable for façade inclusion in city modeling.
Even panoramic cameras have been made digital with the Visionmap A3 (Israel), which permits to acquire super large frames, enabling 3 times the productivity of standard frame cameras.
High Resolution Imaging Satellites
The development of satellite technology since Sputnik in 1957 has been very rapid. Landsat 1 became the first remote sensing satellite with a global coverage in 1972 with a ground sample distance GSD of 80m. Spot 1 in 1986 was the first operational mapping satellite with 10m GSD. The Indian satellites IRS 1C and 1D followed in 1997. In 1999 Ikonos was launched in the USA with 1m GSD. This was followed by Quickbird in 2002 with 0.6m GSD, in 2007 and 2008 by World View 1 and GeoEye 1 with 0.5m GSD. Even 0.25m GSD satellites have been announced (GeoEye 2).
What is equally significant, is that this development is not limited to US satellites, but that several other nations now launch high resolution satellites with 2.5m GSD or better, such as: Taiwan (Formosat 2,2m GSD in 2004), India (Cartosat 1,2m GSD in 2005; Cartosat 2,1m GSD in 2007), England (Topsat, 2.5m GSD in 2005), Japan (Alos, 2.5m GSD in 2006), Israel (EROS 1B, 1m GSD in 2005), Russia (Resurs DK1,1m GSD in 2006), Korea (Kompsat, 1m GSD in 2006), Thailand (Theos, 2m GSD in 2008), Nigeria (Nigeriasat, 2.5m GSD in 2008), Dubai (Dubaisat, 2.5m GSD in 2009), China (ZY3,2m GSD in 2011).
Another advance was the capability to permit changing view directions from the satellite. Previously SPOT permitted this by a slow movement of a rotable mirror. With new satellites, such as GeoEye fast rotations of the entire satellite are now possible under star tracker control.
High resolution satellite imagery therefore has become competitive with respect to aerial surveys at medium and small scales.
Stereo Image processing Software
The early attempts of inefficient automatic stereo image processing, limited by computer hardware, carried out at IBM in 1965 (John Sharp) have now led to efficient commercial matching software (Trimble-Inpho, Leica-Erdas, Intergraph, SocetSet and Racurs). This software now permits a semi-automatic creation of digital surface models DSM from stereo imagery.
An even more efficient automatic image processing algorithm has been introduced by “Pixel Factory” of EADS, and perhaps also by Microsoft-Vexcel Ultramap.
Radar and Laser Scanning
Laser scanning, which has become operational, is not the first active sensor use for geoinformatics. Since the 1960's airborne radar has been operated from aircraft. The development of the synthetic aperture radar SAR has improved the radar resolution for use in aircraft (GEMS) and on satellites (TerraSar X and Tandem X). Radar applications are a useful option, in cas meteorological conditions prevent optical imaging. For mapping radar applications are generally limited to small scale. However, interferometric applications have created new possibilities for change detection of the terrain with high accuracy.
Active sensor technology at large scale has been developed in 3 fields using lasers:
- Airborne laser scanning
- Terrestrial laser scanning
- Mobile laser scanning
Airborne laser scanners have succeeded to become an excellent tool for the survey of digital elevation models with about double the accuracy, which can be obtained by photogrammetry from the same flying height.
Moreover, in forested terrain, lasers have become successful in penetrating the foliage, so that laser returns can be received generally from the top and the bottom of vegetation, giving the opportunity to derive digital surface models (DSM) for the top of vegetation or buildings and digital terrain models (DTM) relating to the ground surface.
Terrestrial laser scanning has proved itself very suitable for the survey of engineering objects and for objects of cultural heritage.
Mobile laser scanning (in combination with optical images from cameras) has become a tool for the survey of street facades and street furniture.
Computer Technology
Perhaps the most important impact on the development of geoinformation technology has been the growth of computer tools themselves, characterized by what is usually referred to as “Moore's Law”. Gordon E. Moore, a co-founder of Intel empirically described the performance of computers and the miniaturization of its components (the number and size of transistors). He found in 1965 that computer performance grew at an exponential rate. This performance continued to grow exponentially from 1971 onward to 2011:
In 1971 the first microprocessor, the Intel 4004 was produced with 2250 transistors with 10^m PMOS technology;
In 1985 the 386™ microprocessor with 27500 transistors was introduced with 1.5 ^m CMOS technology;
In 2007 the CoreTM multicore processor was created with 45nm technology.
The Pentium4 Processor now has more than 100 M transistors.
In 2011 trigate transistors were introduced again increasing the number of transistors which can be accommodated per area, reaching 200B transistors per processor.
This resulted in a doubling of computer performance every 18 months, which is predicted to go on until 2013, and from then on every 2 years for at least the next decade.
But of equal importance now is also the speed of networking between computers, which in recent years has doubled every 9 months.
The stages have been:
GPRS 114Kbps
Bluetooth 723Kbps
ISDN 0.144 to 1.544 Mbps
Ethernet 10Mbps
glass fiber 10Gbps
During the last 10 years the computer performance has increased 60 times, and the networking capability 4000 times.
This means we are able to tackle tasks we could not do 10 years ago.
Data Base Technology
Linked with the capabilities of computer performance are the software aspects of database technology. While computer storage is no more a handicap, faster data access form the data base can now be achieved by indexing.
Geometric representation in 2D, 2.5D or 3D has been developed with line graphics, prevalent in CAD systems (Autocad, Microstation). This took care of mapping and design needs.
Analysis capabilities have been added by GIS Systems with relational data bases, which permitted to store geometry with topological relations in 2D (ESRI ArcGIS, Oracle Spatial). These GIS systems permitted to establish geodatabases with mapping and analysis capabilities.
The competition for the efficient vendor developed systems comes from the Open Source Community (e.g. GRASS, PostGre).
Web Technology
Organizations in charge of administering data bases must be concerned to disseminate their data content in whole or in part. This has led to the development of geoportals for viewing the data content and for extracting the relevant graphic and non graphic information.
Geoportals will only work efficiently within a fast computer network. Special concern must be given to the access conditions within the network and if charges for data are to be made, there must be an accounting system included.
Mobile Communication Technology
The latest trend to make interactive graphical and non-graphical information publicly available is through telecommunication networks using smart phones (Iphone) or tablets (I-Pod).
With new data providers, such as Google Earth, Google Maps or Bingmaps such devices have been able to integrate the geoinformation capabilities:
1. A mobile GIS can integrate aerial images and satellite images
2. It can display and superimpose available and augmented maps
3. It can incorporate address searches and street views
4. It can act as navigation device
5. It can incorporate 3D views and 3D city models
Conclusion
1. After 134 years of existence of the International Federation of Surveyors and after 101 years of existence of the International Society for Photogrammetry and Remote Sensing, and after 52 years of existence of the International Cartographic Association geoinformatics is an independent discipline providing spatial information to the society.
2. We need continuous input from sciences and other engineering disciplines, but the continued growth in computer performance guarantees our own continued growth.
3. The society needs our services, which only we can provide because of our professional interest and concern.
What are the problems geoinformatics is facing? These are more sociological than technical in nature:
1. Do we have political support
2. Do the laws protect our professional status?
3. What esteem do we have in society as engineers?
4. The answer is that we have to get engaged in social, political and ultimately ethical issues.
© G. Konecny, 2012
