Applications Of A Modern GIS(Geographic Information System) Geodatabase In Geotechnical, Geophysical And Geological Analyses

Abstract

GIS Database Description In 1989, Qatar set in place a strategy and vision for the world's first integrated national GIS (Geographic Information System). Today, the implementation of that vision plays a major role in integrating diverse multi-scale, multi-disciplinary spatial data from geological rock samples to multi-spectral satellite imagery for use in solving complex geological, geophysical, geotechnical and environmental problems. GIS data from all of Qatar's ministries can be incorporated into a single analysis, including soil type, land use, surface geology, structure, topographic digital elevation model (DEM), satellite imagery, roads and cultural data. Through GIS, these data are rapidly incorporated with proprietary data from borehole cores, seismic survey data, engineering facilities and infrastructure. The strengths of the ArcSDE geodatabase lie in three areas that are the topic of this paper. First, the power of integration of information from such disparate sources as surface mapping, borehole geotechnical data and satellite imagery. Second, GIS databases capture the source and quality of input datasets. Data from different sources differ in quality, structure, resolution, classification methods, projections and accuracy. GIS analytical tools resolve the differences between sources, producing the best possible data for analyses. Third, analytical methods are readily captured in the GIS metadata structure. Several examples presented here from Qatar illustrate the value of an integrated GIS in decision making for solving industrial, geotechnical, environmental and geological research problems. Since 1990, industry initiatives (e.g. POSC) have set to improve data sharing and quality. Major advances have been made through GIS systems. Data are now georeferenced to a known datum and projection - vector and image data can be readily re-projected to any specified datum and projection instantaneously. Metadata explains exactly the resolution, accuracy and data gatherer's intent. Metadata is data about data. Metadata is additional information (besides the spatial and tabular data) that is required to make the data useful. It represents a set of characteristics about the data that are normally not contained within the data itself. The use of metadata in the geodatabase ensures that all available defining information about the data is known. Details about sources, precision and format are captured. Quality assurance is an inherent property of the GIS database. GIS combines the visualization features of maps (spatial data) with the processing power of tabular data (attribute data). It provides the ability to browse and zoom into areas of interest. Point, line or area information may be queried. Qatar's geodatabase includes Landsat, SPOT, Quickbird and IKONOS satellite imagery (to 60cm resolution), DEM, roads and cultural data. Qatar Petroleum's geodatabase includes oil and gas facilities (e.g. wells, pipelines), topography and 20cm aerial photography. Qatar's ArcSDE data server was designed for access to GIS data in any format and datum, and to use multiple database management systems concurrently. The geodatabase provides: high-performance; spatial integrity; management of extremely large data volumes; a common interface to database management systems; support for industry data models; and integration of multiple data types such as raster (images) and vectors.