Mathematical Geology, Vol. 26, No. 4, 1994
Book Review Computer Modeling of Geologic Surfaces and Volumes Edited by David E. Hamilton and Thomas A. Jones American Association of Petroleum Geologists, Tulsa, Oklahoma, 1992, 297 p., hardcover, $66 (U.S.; for non-AAPG members), ISBN 0-89181700-X
Contouring geologic data, either by hand or automated process, is a practice at least several centuries old. Today, contouring geologic data is often accomplished by machine. But, a machine cannot render its own decisions with respect to geologic knowledge (with all due respect to researchers interested in artificial intelligence) when preparing maps. Hence, whereas computer contouring geologic data is convenient, computer-generated maps may not adequately reflect geologic knowledge. The major theme of this book is that blind processing of geologic data by computer often leads to erroneous geologic modeling, therefore a geologist must often proceed through several iterations of computer-aided mapping, correcting flaws then remapping, before a final map is produced that adequately represents geologic knowledge. This theme is established in Chapter 1, "A Philosophy of Contour Mapping with the Computer," penned by the editors. The abstract to this chapter opens with the sentence, "Geologic interpretation is a critical requirement for mapping geological valuables." Thus, the tone is set for the rest of the book. Figure 1 of this chapter shows an interesting experiment to contour structure on pinnacle reefs. This experiment is described in detail in Chapter 5, "Computer Mapping of Pinnacle Reefs, Evaporites, and Carbonates: Northern Trend, Michigan Basin," written by David Hamilton and Skye Henize. Blind computer contouring of these data does not adequately represent the structure of the pinnacle reefs; only after a filter is applied to the contouring results does the map appear to be appropriate. Experiments such as this are documented in this book and, as a result, make it a valuable addition to anyone's library who is interested in spatial data analysis. This book is related to an earlier book edited in 1986 by Tom Jones, David Hamilton, and Carlton Johnson, Contouring Geologic Surfaces with the Com-
519 0882-8121/94/05004)519507.00/ I i~/ 1994 I nternational Association for Mathematical Gcoiogy
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puter. Precisely how this current book is related to the earlier book is stated in the preface: "In 1986, with Carlton Johnson, we published the book, Contouring Geologic Surfaces with the Computer. That book generally has been well received. There have been comments, however, that examples that apply the methods to real situations are needed. Based on that feedback and discussions with mapping software users, we realized that the geologic mapping community needed more than a second edition with a few added examples. We decided that a new mapping book, covering a wide variety of geologic settings and a large number of applications, would be more valuable." A list of chapters and authors underscores this preface. Chapter 1 and 5 are mentioned before. In addition to these, Chapter 2 covers graphical techniques for locating anomalies and is an excellent overview of what is basically a rasterbased geographic information system (GIS) and shows excellent color photographs of composite Landsat/geophysical data displays. Chapter 3 discusses a shape-assist technique to incorporate stream channel interpretations into computer-generated surface models; this chapter is a furtherance of the theme of this book that initial contour maps should be manipulated (adjusted) to conform to known geologic knowledge. Chapter 4 is a documentation of computer-generated surfaces and grids of the geometry, rock type, and chemistry of a bedded mineral deposit. Chapter 6 is a continuation of the geologic study described in Chapter 5 pertaining to pinnacle reefs. Chapter 7 documents the modeling of anisotropy when mapping geologic data by computer. The eighth chapter discusses surface modeling for sedimentary basin simulation. Chapter 9 shows tests of hydrocarbon saturation models for use in original oil-in-place estimation in specific application to South Dome of Oregon Basin Field, Park County, Wyoming. Moreover, Chapters 10 through 12 represent a collection of three papers showing how to account for faults in automated mapping of geologic data. These first 12 chapters document two dimensional mapping applied for geological analysis. Beginning with Chapter 13, the book makes a transition into a discussion of three-dimensional modeling applied to geologic data; in fact, Chapter 13 represents an introduction to the section of the book devoted to three-dimensional modeling. Six chapters, Chapters 14 through 19, discuss three-dimensional modeling. Chapter 14 discusses a model of a polar fan-delta complex in Alaska. Chapter 15 discusses a three-dimensional model of a massive sulfide deposit in British Columbia, Canada. Chapter 16 is devoted to volumetric calculations for hydrocarbon. Chapter 17 shows an application to Canadian oil sands. Chapter 18 is an analysis of a mature stream drive. Finally, Chapter 19 discusses three-dimensional modeling of geologic structures. As perhaps mundane as a summary of chapters is, in this case a topical summary of the 19 chapters shows how extensive this book is in treating computer mapping problems faced by geologists and geological engineers. A reader
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will not find listings of actual computer software; all 19 papers assume a reader has access to software to implement methods. Rather, each paper is a discussion on the suggested use of software to obtain correct geologic interpretations. Such papers are necessary, timely, and extremely well presented in this book. The editors have done a fine job in reviewing papers and assembling them thematically in this volume. Of the collection of 19 chapters, I am especially impressed with Chapters 5 and 6 dealing with the accurate computer mapping of the structural tops of pinnacle reefs. In fact, Appendix B contains a complete listing of the data for the pinnacle reef study. Hence, any researcher having access to mapping software can perform experiments to accurately map these data or reproduce figures in the book. In addition to the pinnacle reef data, Appendix B contains complete listings of four other datasets: structural top of a coal unit, data from an undulating bathymetric surface, data for sediment thickness in a delta, and data for sediment thicknesses in stream channels. Anyone who is seeking complete listings of spatial data, either for research or the classroom, will appreciate this book. Because this book is published by the American Association of Petroleum Geologists, and the editors themselves are either employed by or affiliated with the petroleum industry, many of the applications contained in this book involve applications in the petroleum industry, or involve applications related to sedimentary petrology. I also feel the treatment given in the book on geostatistics and analysis of anisotropic spatial correlation is rudimentary. Furthermore, information presented showing composite display of Landsat data with other data types is not new; such composite displays have been used since the 1970s and nothing new is presented in this book. Finally, the book does not discuss how artificial intelligence (AI) techniques might be used to improve geologic mapping. In my opinion, these are the total of the negative comments that might be levied against this book. Further, in my opinion, these are not strong negatives; in fact, for readers who are not knowledgeable in geostatistics or remote sensing, chapters in the book represent a clear presentation of techniques. Being knowledgeable in remote sensing, I feel that even though the chapter on digital imagery presents nothing new, the chapter is well presented and the figures outstanding (and published in color). AAPG has done a good job producing this book. The cover jacket is colorful and well designed using many of the composite digital image displays contained in the book. The format of the book is large, each page measuring 8.5 inches wide by 11 inches long (21.5 cm wide by 28 cm long). Papers are printed on white, glossy paper using a double column format. Hence, even though the book is only 297 pages long, the information contained in the book equals or exceeds that in a book twice as long that employs a single column
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format. I highly recommend this book to anyone interested in computer mapping of geologic data. James R. Cart
Department of Geological Sciences/] 72 University of Nevada Reno, Nevada 89557-0138
