CaGIS vol. 31, no. 3

2004

Foreword

Mobile Mapping and Geographic Information Systems

Keith C. Clarke

Mobile mapping and geographic information systems may represent a new paradigm for cartography and GIScience. This short foreword to the special issue introduces the three papers that follow, briefly surveys the growing literature of field and mobile GIS, and discusses the emerging literature surrounding wearable GIS and their augmented reality display systems. The UCGIS research agenda for mobile and distributed computing is presented, as are the calls for additional research in the papers of the special issue. Calls for a comprehensive review article of the field from a cartography/GIScience perspective, and for involvement in the research agenda of mobile systems, are made.

KEYWORDS: Mobile GIS, visualization, wearable computing, augmented reality

Flexibility by Design: How Mobile GIS Meets the Needs of Archaeological Survey

Nicholas Tripcevich

Handheld computers have become capable of more than data storage and precision measurement; they have begun to contribute to scientific studies conducted in demanding field research settings. Recent versions of mobile GIS software allow researchers with limited programming skills to tailor the software to the priorities and theoretical needs of individual research projects. Depending on the research needs in a given situation, data recording can be expedient or thorough, and data acquisition forms can be designed to emphasize flexibility for varied or unpredictable field conditions. By giving researchers access to large digital datasets and spatial analysis tools while in the field, mobile GIS facilitates the data acquisition process and can contribute to the quality and the efficiency of fieldwork. In this study, the implementation of ESRI Arcpad 6 in a high-altitude archaeological survey project in Peru presented challenges to the mobile GIS system that are perhaps common to many mobile GIS-based scientific fieldwork projects. The paper discusses the benefits and the limitations of doing an archaeological survey using mobile GIS. It also considers some of the ways in which improvements in mobile GIS technology will facilitate the methods of resource managers and field scientists in the future.

KEYWORDS: Mobile mapping systems, rugged field GIS, archaeological survey

Integrated Mobile GIS and Wireless Internet Map Servers for Environmental Monitoring and Management

Ming-Hsiang Tsou

With the progress of mobile GIS technology there is a great potential for adopting wireless communications and Internet mapping services for regional environmental management programs and natural habitat conservation. This paper provides an overview of a NASA-funded research project that focuses on the development of mobile GIS tools and wireless Internet Map Server (IMS) services to facilitate environmental monitoring and management tasks. By developing and testing wireless web-based map/image servers, mobile GIS applications, and global positional systems (GPS), this research created an integrated software/hardware infrastructure for a prototype mobile GIS application. The mobile GIS prototype allows multiple resource managers and park rangers to access large-size, remotely sensed images and GIS layers from a portable web server mounted in a vehicle. Users can conduct real-time spatial data updates and/or submit changes back to the web server over the wireless local area network (WLAN). This paper discusses in general the major components of mobile GIS, their current technological limitations, and potential problems during implementation. Key research agenda for mobile GIS are identified with suggestions for future research and development.

KEYWORDS: Internet mapping, mobile GIS, GPS, wireless communication

GQMAP: Improving Performance and Productivity of Mobile Mapping Systems through GPS Quality of Service

Hassan A. Karimi and Dorota A. Grejner-Brzezinska

Today’s mobile mapping systems (MMS) benefit from an array of sensors and technologies to collect precise data on roadways. Data collected by MMS include spatial and attribute information on various objects of interest. The global positioning system (GPS), usually differentially corrected, is one of the essential positioning technologies currently used in MMS, which is often integrated with other positioning technologies, such as inertial navigation systems (INS), differential odometers, and digital compasses. As GPS is the most dominant positioning technology in MMS, we propose an innovative approach in utilizing GPS in order to improve its performance and productivity, and to reduce the operational costs of MMS. To that end, we present and discuss in this paper GPS quality of service (QoS) and a novel approach called GPS QoS MAP (GQMAP) to reliably predict optimal data collection strategies using MMS.

KEYWORDS: Mobile mapping systems, GPS, GPS quality of service

Semi-Automatic Modeling of Buildings from Digital Surface Models

Daniel R. dos Santos, Antonio M. G. Tommaselli, and Quintino Dalmolin

Semi-automatic building detection and extraction is a topic of growing interest due to its potential application in such areas as cadastral information systems, cartographic revision, and GIS. One of the existing strategies for building extraction is to use a digital surface model (DSM) represented by a cloud of known points on a visible surface, and comprising features such as trees or buildings. Conventional surface modeling using stereo-matching techniques has its drawbacks, the most obvious being the effect of building height on perspective, shadows, and occlusions. The laser scanner, a recently developed technological tool, can collect accurate DSMs with high spatial frequency. This paper presents a methodology for semi-automatic modeling of buildings which combines a region-growing algorithm with line-detection methods applied over the DSM.

KEYWORDS: Laser scanner, laser scanner image, semi-automatic extraction, building modeling

Book Review

Groundwater Modeling Using Geographical Information Systems, by George F. Pinder, John Wiley and Sons, Inc., 2002. ISBN 0-471-08498-0. 233 pp. CD. Hardcopy $90.

— Reviewed by David L. Ozsvath, University of Wisconsin

Although groundwater professionals have been learning to incorporate the power of geographic information systems (GIS) into their modeling efforts for some time now, this is the first attempt to present such information in a textbook format. However, despite its title, this book is written primarily for advanced undergraduate or graduate students taking a course in groundwater flow or contaminant transport modeling (the author mentions in his preface that the book is an outgrowth of his teaching such courses at Princeton University and the University of Vermont). Therefore, GIS is simply the means to an end, and there is no attempt to introduce readers to the fundamentals of GIS or to its full range of capabilities.

The interest in GIS by groundwater professionals stems from the fact that flow models are highly dependent upon geospatial information, such as base maps, model boundaries, the variations in hydrogeologic properties and recharge, and the locations of groundwater sources and sinks. The previously time-consuming and tedious work of creating these geospatial databases can now be automated using GIS, which serves as a highly sophisticated pre- and post-processing system for the actual flow or transport model. Alternatively, where appropriate GIS databases already exist for a study area of interest, this information can be imported into the geographical information modeling (GIM) environment and incorporated into a groundwater model. The end result is that modelers spend less time creating their models yet have greater ability to examine how changes to the input values, discretization, and boundary conditions affect the model output.

Pinder presents only one GIM software package—the Argus Open Numerical Environment (or Argus ONE)—which is apparently the system he uses in his courses. Although Argus ONE is able to import files created in other programs (such as AutoCAD or ArcView), the book does not provide any guidance on how this is done. In keeping with the author’s main objective, the reader is simply given instructions for using Argus ONE with either the Princeton Transport Code (a groundwater flow and contaminant transport model written by Pinder) or the USGS flow and transport models known as MODFLOW and MT3D, respectively.

The book includes a compact disc that contains the Student Version of the Argus ONE GIM system along with the necessary graphical user interfaces (GUIs) and plug-in extensions (PIEs) for MODFLOW and MT3D. In addition, the author’s Princeton Transport Code (PTC) and related GUI and PIE can be downloaded from a website maintained by the publisher. I also noticed that the compact disc contains two other USGS programs (SUTRA and HST3D), although these models are not mentioned in the text.

Installing the software on my desktop computer (a Pentium 3, 1.0 GHz, with 256 MB of RAM) was straightforward; however, I encountered difficulties when attempting to run the programs. The Argus ONE support staff was quite helpful in resolving these problems (which are apparently related to the fact that my computer operates with Windows 98 rather than a later version), but it is still impossible to run the modeling programs unless all unrelated programs are shut down. I was told that those with other versions of Windows would not experience the same problems.

The book is divided into three parts (Flow Modeling, Transport Modeling, and Finite Element versus Finite Difference Simulation), with a majority of the text devoted to the first topic. In general, each of these chapters is well organized, and Pinder is careful to identify terms and acronyms as they are introduced. Throughout the book, information from an actual groundwater contamination site in Tucson, Arizona, is used to illustrate the various aspects of creating and running both flow and transport models. Readers are also provided with the necessary data and step-by-step instructions to recreate this case study model for themselves. Because the text is enhanced with more than 150 illustrations and screen captures, the modeling instructions are relatively easy to follow.

Part One (Flow Modeling) covers the theoretical background required to understand groundwater flow models, including mathematical derivations of the governing flow equations. In sequential fashion, Pinder discusses the collection of site information, the development of a conceptual model, the representation of site conditions with an appropriate numerical model, simulation and output, and, finally, model calibration. I was surprised that Pinder devoted 25 pages to a review of basic geologic environments and the techniques used to compile geologic and hydrogeologic data for a conceptual model. This section seems tangential to author’s main objective and is inconsistent with the level at which the rest of the book is written. It would be better to refer readers to other sources of this information, or to perhaps include it as an appendix.

Part Two (Transport Modeling) follows a format similar to Part One in first deriving the differential equations that govern contaminant transport by groundwater and then stepping the reader through a process of model development, simulation, and calibration. However, in contrast to his treatment of basic geology in Part One, Pinder here seems to assume that his reader is familiar with groundwater geochemistry and the influences that subsurface conditions can have on the behavior of contaminants. This allows him to greatly abbreviate his discussion of geochemical reactions and thus focus on the techniques used for modeling.

Part Three (Finite Element versus Finite Difference Simulation) contrasts the construction and use of finite-element models (represented by the PTC) with finite-difference models (represented by MODFLOW and MT3D). Pinder not only discusses these two types of models but also illustrates the differences by stepping through their input requirements and then contrasting their outputs for the Tucson case study. This chapter is very useful to those who are new to modeling and unfamiliar with the strengths and weaknesses of the finite-element versus finite-difference models.

Despite that fact that Pinder only considers one GIM package and does not explore the full range of GIS capabilities, I am favorably impressed with this text, particularly for use in the classroom setting. The book’s primary strength lies in its use of the Tucson case study, which allows the reader an opportunity to gain “hands-on” experience while learning the conceptual framework for models. Aspiring groundwater professionals will also benefit from Pinder’s wealth of knowledge, as revealed in his modeling tips, “rules of thumb”, and insight into various modeling strategies. For this reason alone, the text is a valuable reference for those who use groundwater models.