Dynamic Graphics, Inc.
1015 Atlantic Avenue
Alameda, CA 94501
Telephone: (510) 522-0700
Fax: (510) 522-5670
e-mail: skip@dgi.com
As of the date of this conference, May, 2001, participating geologic survey organizations are making progress in cataloguing existing geologic maps and related data, and designing and implementing data models and database structures for the subsequent inclusion of the catalogued maps and data in compatible databases. These efforts significantly improve the chances that a geologist beginning a new investigation will be able to find and review all or most previous work related to the area of interest. This is a necessary, formidable first step in a process of increasing the utility of the geologic mapping process and its outputs to society.
As this effort progresses, survey organizations face additional challenges, born of technological advance, that will need to be addressed. Enormous volumes of data related to geology are being gathered by governments and by commercial organizations. By law, and under varying time scales, most of this data becomes public property without legal access restriction. Remotely sensed geophysical data is the most rapidly proliferating form, but boring/well logs, cores, well tests, and geochemical analyses, form part of a long list. This data explosion has some important characteristics. First, much of the data concerns the subsurface, yielding the greatest value when it is used in a full, three-dimensional context. Secondly, it is numeric, in most cases, and often cannot be summarized effectively in a planimetric representation. Certainly some of the data requires animated three-dimensional representations to capture a fourth dimension. Finally, some of the older data and almost all of the recently gathered and produced data are in digital form, either numeric, or in formats that can often be used by clients, the data consumers, in subsequent computer processes before those data are distilled in a report, map, graphic, or other representation. The polygons and lines that reflect the stratigraphy and structure in a traditional geological map are the true product, not the map itself.
The customer interface for provision of geologic data is oriented to traditional paper systems or to digital analogues of those paper systems. Catalogs and tables, with indexical maps and graphics provide orderly access to bins of maps and directories of digital files. This system works well, but it lacks one desirable feature a general ability to relate each of the available data sets in a given region to the others spatially.
Some
Because the three and four-dimensional models can provide a rich spatial context for most types of data, care must be taken in accurately conveying the character of each data set represented. Raw data, "cleaned" data, models, and more generalized knowledge are all appropriate components of a regional geological index model. The degree of interpretation and integration are the variables in the progression from raw data to a regional geologic model. Descriptions of the interpretation and integration processes become part of the model metadata.
In the realm of more or less pure data, we deal with topographic and surficial descriptions of geology, boring and well data directly or geophysically sampled, image data, and a bewildering variety of geophysical data with varying spatial contexts. The list includes many more geoŠ and paleoŠ data types. Almost every type of data here actually requires a measure of processing by a geoscientist to become what most of us would call a useful data set for general consumption. As we move from the types of information we tend to call data to the class we call models, we are dealing with the degree of interpretive input, not the sudden introduction of interpretation to the process.
Models ultimately need to use as many dimensions as necessary to integrate their data inputs. If all you have are data relating to surface locations, with some shape for the surface, a three-dimensional surface model is sufficient. When you begin to integrate, or just represent, many data sources into a regional model, the use of volume models, possibly with the addition of a fourth dimension for time becomes almost unavoidable. Perhaps not as numerous as data types, volume model types run the gamut from structure and stratigraphic models which then allow introduction of properties related to the surfaces and volumes, to dynamic models concerned with structural, thermal, fluid, and geochemical variation over time. A feature of models with more dimensions is the potential for using different representations for specific purposes. Sections, contour maps, and thematic maps can all be derived from the 3D models with significant improvements in spatial consistency, containing additional information that can only be derived from a three of four-dimensional model.
The knowledge component that should accompany the collection of the data and model representations would include the interpretive descriptions and discussions related to the current representations as well as the those of the past, contextual information, and relational information. All of these could be available in text, audio, multimedia, and video form. The three or four-dimensional model could key these elements as easily, though not so directly as the data and models.
Is it currently possible to use a three-dimensional geologic model as a visual key for all the data types mentioned? Yes, with development that would only involve adaptations of processes that have already been put in place for similar purposes. An ideal combination of development partners would involve
The projects on the distributed
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Shilts, W.W., Lasemi, Zakari, Mikulic, D.G., and Abert, C.C., 1999, Geologic Mapping of the Villa Grove Quadrangle, Illinois: Illinois State Geological Survey.