THE ROLES OF GIS IN BUILDING THE EARTH INFORMATION SYSTEM 12.1 May Yuan The University of Oklahoma, Norman, Oklahoma 1 INTRODUCTION The EIS envisioned here is a comprehensive and integrated system that Geographic Information Systems (GIS) monitors natural and built environments, emerge as an enabling technology for integrates, manages, and disseminates data geospatial data handling, integration, of physical and human environments, analysis, modeling and visualization. With a synthesizes data from multiple variables wide range of spatially enabling functions, across scales in space and time, formulates GIS technology and the science (GIScience) new knowledge, explores patterns of interest that underpins the technology ought to play and visualizes findings to facilitate a central role in building the earth understanding. Hence, a comprehensive information system (EIS). In practice, EIS consists of not only “a four-dimensional however, GIS technology has not yet been gridded set of quantitative, geo-referenced fully recognized in scientific information data” or “a digital earth” but tools and management and computing. Many procedures to reason, analyze, model, and technological and societal barriers constrain visualize the dynamics of the earth systems. the use of GIS technology in scientific inquiry. Societal barriers may be overcome To date, we have a suite of remote by organizational and institutional solutions, sensing and surface observing systems that such as setting data standards and open- regularly take measurements around the source means. Technical advances require world (Mikusch et al. 2000). Although many strengthening GIScience fundamentals and gaps exist, especially in ocean observations, technological innovations for direct and NOAA, NASA, and USGS have been robust information support. partnered with international organizations and the private industry to implement and This paper emphasizes the need for promote integrated earth observation scientific and technological innovations to systems across the world. Many specialized empower GIS roles in support for EIS programs have been developed by research development. While the significance of communities and the industry for data societal barriers cannot be over-stated, assimilation, information synthesis ad theses barriers will not be discussed in this visualization, and knowledge acquisition. paper for two reasons. First, they are well While GIS technology has much to offer in recognized by government organizations, these areas, the linkage of GIS to these developers and users, and therefore, much specially developed data analysis and resource has been allocated to develop computational models is, unfortunately, solutions for data standards, interoperability, weak. Adoption of GIS technology to and portals, such as major progresses and atmospheric research, for example, is still in accomplishments by the OpenGIS its infancy, and applications appear limited Consortium, USGS, FGDC, NASA and to data distribution, mapping, and simple NOAA. Secondly, removal of societal spatial query and analysis. There are many barriers facilitates data exchange and reasons contributing to limited GIS distributions but has very limited effects on applications in scientific computing and the relevance of GIS technology on scientific ultimately the marginal attention given to computing, which demands computational GIS in building the earth information system. support for data analysis, modeling, and One fundamental issue relates to the lack of visualization. GIS support for 4D spatiotemporal data and the use of GIS as a mapping system, rather Unidata Thematic Realtime Environmental than an information system. Distributed Data Services (THREDDS) (Domenico 2002). However, as specified by This paper calls for a multi-system the Federal Geographic Data Committee approach to integrate existing databases, (FGDC), the content standard for digital information systems, and modeling geospatial metadata (http: //www.fgdc.gov/ environments to achieve a comprehensive metadata/csdgm/) is considerably limited to and integrated EIS that can effectively information pertinent to maps and specific to facilitate understanding and reasoning both individual data sets. The lack of means to physical and human dimensions of the cataloging data that are spatially and dynamic world through monitoring, temporally correlated may have constrained integration, analysis, synthesis, modeling access to geospatial data. For example, the and visualization. Figure 1 illustrates the development of a severe weather event components of a comprehensive EIS. GIS (such as Hurricane Ivan) may be captured technology has much to contribute in by multiple sensors and observing networks management, dissemination, analysis, (radars, GEOS, MODIS, etc.) across space modeling, and synthesis. and over time. Geospatial meta-data should provide mechanisms to relate all kinds of data corresponding to a certain event. 2 MANAGEMENT Manual documentation of such meta-data seems impractical. Alternatively, GIS GIS technology is designed to manage functions of spatial overlays and buffering geospatial data. Its capabilities to can be used to automate the process. georeference data and associate attributes Spatial overlays of the path and outlines of at locations enable spatial integration of data Hurricane Ivan to other data sets can reveal from multiple sources. Data integration is related data sets from other sources that critical, since Earth should be considered as also capture the hurricane. an integrated system (Carr 2001). The integration allows users to query information Spatiotemporal query support can based on locations or spatial relationships be greatly enhanced with the additional embedded in geospatial data. GIS has been meta-data across multiple sources because recognized as a powerful tool for spatial the user is able to identify or retrieve data of data management (Kingsbury 2001). interest based on spatial and temporal Beyond basic spatial search and geospatial relationships among geographic phenomena data retrieval, GIS technology can advance and events (Yuan and McIntosh 2002). For the levels of information query, analysis, and example, we can submit a query to retrieve modeling by incorporating temporal and data at stream gages within the path of spatial data and meta data to represent Hurricane Ivan and 7 days before and after geographic dynamics. the arrival of the hurricane. GIS technology ought to provide the needed capabilities that Meta-data is central to geospatial spatially and temporally relate data sets by data management. GIS meta-data cataloging georeferenced features and document, in general, geo-referencing events and applying such catalogs for data information, attribute definitions, and data access. sources and credits. These kinds of information are useful to determine the proper use of a data set. The development 3 DISSEMINATION of digital libraries has pushed the needs of data catalogs that highlight the essential Data dissemination serves two purposes: (1) content of a data set. Significant efforts in distributing data to the user, now mostly via cataloging geospatial data contribute to the the internet; and (2) interfacing the data and implementation of Alexandria Digital Library, the user by visual means. These data can meta-data catalogs at Center for be observations or results from analytical or International Earth Science Information modeling. In a broad sense, GIS technology Network (CIESIN), NASA’s Earth Data is contributing to building the EIS. As the Information System (Schaefer 1995) and internet GIS technology becomes popular, A Comprehensive Earth Information System Monitoring satellites remote sensing surface observing networks Management geo-referencing Dissemination assimilation Distribution integration Visualization query Analysis Modeling Synthesis spatial analysis geospatial models reasoning temporal analysis statistical models knowledge base Spatiotemporal analysis numerical models data mining simulation models Figure 1: Components of a comprehensive earth information system. Arrows indicate directions of data flows. many web-based geospatial data clearing dissemination and, moreover, visualization, houses and data portals disseminate diverse analysis, and modeling. geospatial data worldwide. While there is no short of success stories on Internet GIS applications, GIS technology is currently not 4 ANALYSIS, MODELING, AND playing an active role in building geo- SYNTHESIS cyberinfruncture. Most GIS software packages are proprietary, which may be one GIS technology offers a suite of analytical of the key factors prohibiting the broad use and modeling functions for geospatial data. of GIS technology in science communities, Unfortunately, there is only limited set of who, like Meteorologists, have been spatial functions commonly used in developing their own data dissemination and geoscientific applications. As mentioned visualization packages that couple well with earlier, most GIS applications are on domain-specific data formats, quite different mapping. While mapping is critical to from the ones used in GIS. For example, visualization and revealing spatial netCDF files store meteorological data in 3D relationships, advanced analytical and space and 1D time. However, true 4D modeling functions can probe new patterns, spatiotemporal GIS data models are relationships, and thoughts into geoscientific unavailable, and therefore, current GIS investigation. technology cannot support adequately