![]() The Evolution in the Geoprocessing TechnologyThis page shows a retrospective view and a prospective view about geoprocessing technology, where it is considered the three generations of Geographic Information Systems. The first generation (“cartographic CAD”) is characterized by a system inheriting from the cartography tradition, with limited database support where the typical working tool is a map (called “coverage” or “information layer”). These systems were designed in the 80s for the VAX environment and - starting in 1985 - for PC/DOS personal computer systems, this system class is mainly used in isolated projects , without being concerned about generating digital data files. This generation also can be characterized as project oriented systems (“project-oriented GIS”). The second GIS generation (“Geographic database”) arrived in the market at the beginning of the 90s and it is characterized by its client-server environment concept, attached to relational database managers and additional packages for image processing. These systems were designed for multi platform environments (UNIX, OS/2, Windows) with a windows based interface, this generation can also be viewed as a supporting system for institutions (“enterprise-oriented GIS”). It is possible to forecast, for the end of the 90s, a new GIS generation (“digital geographic libraries” or “Geographic data centers”), managing large databases of Geographic data, with network accessibility, either local or WANs, with a WWW (World Wide Web) interface. For this third generation, the growing of spatial database and the requirements for sharing them with other institutions requires distributed and federative database technologies. These systems must follow the interoperability requirements, such that it allows access for spatial information for distinct GISs. The GIS third generation can still be viewed as the system development for information exchange among institutions and the other society components (“society-oriented GIS”). The next figure shows the evolution of the Geoprocessing technology.
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![]() The first generation: cartographic CADThe first GIS generation is characterized by system with graphical and spatial analysis operations on files (“flat files”). Its connection with database managers is only partial (part of the descriptive information are found in the file system) or non-existent. They are more adequate for spatial analysis project development over small or mid size regions. These systems emphasize mapping aspects. The system allows the data input without previous definition of the conceptual scheme, looking like CAD environments that have cartographic projections representation capability and also attributes and spatial objects association. By conception, these environments do not have adequate support to build large spatial databases.
Utilization To mention just a single example, the “SOS Mata Atlântica” project produced one of the largest worldwide studies using the GIS technology. More than 200 charts in the 1:250.000 scale were produced showing all the coverage of original tropical forest remains, using photo-interpretation of satellite images. Besides the excellent quality obtained, the final results were not consolidated in a Geographic database.
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The second generation: Geographic DatabasesThe second GIS generation is characterized by systems conceived to operate as a Geographic database. It was designed as a non conventional database where the data handled has descriptive attributes but also a geometrical representation in the Geographic space. The second system generation is still under development, with new products being designed and introduced in the market. No available product today shows all requirements presented here although the industry have indicated their product releases should be compatible with the following requirements.
REQUIREMENTS
Utilization The client-server environment usage requires competence in Database administration and Computer Networks, which is not available in institutions that use Geoprocessing. It also requires a larger investment to buy, install, and operate database management systems (DBMS) in the market. Additionally, the large integrator potential of GISs can only be used when the system is integrated with production process. This requires that corporative databases have to be translated to the same DBMS environment used by the GIS. An excellent example of the GIS usage in the client-server environment is the SAGRE system, developed by CpqD/TELEBRAS. Starting from the support offered by the GIS (VISION) and by a DBMS with long fields (ORACLE), it was built facilities for operation and management of the telephone network. This environment is being installed in telephone companies all around Brazil.
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The third GIS generation: Digital Geographic LibrariesA digital Geographic library (or a “Geographic data center”) is a Geographic database shared by a set of institutions. This library has to be remotely accessible and stores, besides the Geographic data, description about the data (“metadata”) and associated multimedia documents (text, photos, audio, and videos). This new paradigm is motivated by our increased interest on the ecological, urban, and environmental problems , trying to understand, in details, local and global changing processes, and by the necessity to share data among the institutions and the society. The basic core of a digital Geographic library is a large Geographic database. To show it, imagine two scenarios: a large Brazilian environmental center and a planning secretary for a mid size city, say about 1 million inhabitants: ·
In these two scenarios, the environment has to guarantee concurrent access to a user community, with different selection methods, including browsing and consulting languages. An example of this technology is the EOSDIS (EOS Data and Information System) system, designed by NASA to be used with the EOS (“Earth Observation System”) program, including a set of satellites with large capability for data generation (2 Tb/day). Considering the general view, the following sections present the main requirements for this new GIS generation, divided into large areas: metadata availability, Internet access, browsing and interoperability.
Requirements: Metadata Another desired aspect in the metadata environment is the availability of synthesis data, such as maps in very reduced scales, that could be used to Geographically localize the available data sets. The ideal situation would be to allow a consulting refinement process, establishing a continuous path between the more abstract metadata level and the data itself (Smith and Frank, 1989). Thus, from the general aspects of the information (“Amazon Database”), it is passed to regional views (“Roraima State”), and specifics (“Roraima Vegetation Maps”) up to the data itself (“The Demene river region Vegetation map in the 1:100.000 scale”).
Requirements: Internet Access However, the WWW environment (using the HTML - Hyper Text Mark-up Language) presents some problems when using together with Geographic databases, mainly because the HTML is navigational and does not carry transaction capabilities. In order to combine in an appropriate way the WWW/HTML technology with a typical consulting environment for Geographic databases, it is inevitable to use, besides the pictorial resources of HTML, the consulting language with spatial constraints.
Requirements: Pictorial Navigation It is important to provide navigation mechanisms, because it is not possible that the user previously knows which data types are available and how to proceed in order to get access to the data. The navigation tools allow the user to access data based on its spatial location. The figure below show a possible partitioning by index-maps from a country, which could be used for navigation.
![]() Index-maps structure for navigation.
Requirement: Interoperability When trying to fix these problems, several countries have being working to define cartographical standard for data transfer, keeping the Geographic information richness (topology and attributes). These patterns try to be “neutral” to several companies, including the SDTS (Spatial Data Transfer Standard) in the USA and the SAIF (Spatial Archive and Interchange Format) in Canada. However, even if the data transfer among Geographic databases is established with different formats, remember that, in complex applications, such as Geoprocessing, a substantial part of the information holds on the consulting, manipulation and presentation procedures. Thus the data interchange does not guarantee interoperability. In this thesis context, there is no way to explore in higher details this fascinating topic, which we hope can be studied later.
The main purpose of SPRING 2.0 is to be a GIS satisfying all the second generation requirements, that is, a “Geographic Database”, so we believe that complete Geographic database is fundamental in the process of building efficient digital Geographic libraries.
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