It is a general consensus among social scientists that a technological revolution of historic proportion is dramatically transforming all the fundamental dimensions of human society. Technological impacts on the spatial forms and dynamics of cities all over the world can serve as the quintessential example for this technological revolution. Yet the recent literature is full of conflicting arguments and untested speculations about the effects of these technologies on urban societies. Although similar conference and projects have been conducted before (Brotchie et al., 1985, 1987; 1991), I believe that the proposed Baltimore conference is timely and much needed as some broader theoretical issues have not been thoroughly discussed and some of the technological advances were not anticipated. The following are some of my research notes prepared for the Baltimore conference. My primary intention here is to present an outline for a new conceptual framework and discuss a preliminary research agenda related to the three conference themes. The new conceptual framework proposed here is a synthesis of existing theoretical frameworks with a very strong flavor of theoretical pluralism. It is just a rough outline at this moment. Hopefully, I can further elaborate this framework based upon the feedback from the participants of this conference. Empirical evidence from my on-going research on Texas cities will be provided at the conference.

1. Metropolis in the 21st Century: Toward a new synthesis of conceptual frameworks

The voluminous recent urban literature on world cities, especially North American cities, is replete with assertions that a major reorganization of the spatial structure of cities is underway. A series of distinctive new urban forms is emerging from a complex interplay among social, economic, political and cultural forces. It has been argued that these new forms are characterized by the continued decentralization of both population and employment, the increasing levels of social diversity and spatial polarization, the emergence of an elite inner city (gentrification), and the deepening spatial separation between jobs and labor (spatial mismatch). These new urban forms have been attributed to the various societal, institutional, and individual decision making processes. Numerous policy proposals have been made for various different development scenarios for cities in the 21st century, ranging from going back to the pedestrian-based more compact urban form to stimulate the development of completely footloose electropolis.
In order to weave all these different aspects of urban studies into a coherent research agenda, we need to develop and articulate a new, eclectic, and inclusive conceptual framework. I believe that the new theoretical framework should have three integral components: 1). It should enable us to describe the new emerging urban forms in more comprehensive ways; 2). It should empower us to explain the underlying processes contributing to the emerging new urban forms; 3). It should offer us new insights to prescribe effective urban policies to redirect the underlying processes to promote the most desirable urban forms.

1.1 Urban Forms: A metropolis in the 21st century will be a tale of three different, but interrelated, cities. The specific urban forms will be determined by the interplay of the following three components:

A. Technopolis: Indeed, new world making always starts with the new word making. Scholars have used a variety of different names to refer to this emerging technopolis, ranging from electropolis and wired cities to city of bits, computational city to virtual and on-line community. Technopolis, narrowly defined, refers to the constellation of massive transportation, telecommunications, and information networks to move goods, people, and information; it is a combination of wheels, wires, and air waves. Technopolis, especially the city of bits, or the on-line virtual community, has attracted lots of attention in recent years, but our knowledge of the wired cities remain to be futuristic prophecies as presented in Mitchell's City of Bits. Concerted research efforts are needed for this emerging new urban form. The three themes of this conference may serve as an excellent start for us to gain more knowledge of this emerging new urban form.

B. Ecumonopolis, also known as sustainable city or ecological city. Daunting urban environmental problems have made the urban community to rethink of its slash/burn policies in the past. The development of Ecumenopolis, with the goal of seeking harmony of human being with their surrounding urban natural environment, has increasingly become an integral part of urban policy for urban development all over the world. The technopolis should be developed in harmony with urban natural environment and ultimately to become an ecumenopolis.

C. Anthropopolis. The central component of metropolis of the future will be the people residing the cities. To make future cities to become anthropopolis is to make future metropolis to become truly the city of/for people. The concept of anthropopolis emphasizes the satisfaction of human needs and the quality of urban life as the ultimate goal for all the future endeavors. We should strive the make the technopolis and ecumenopolis to serve this goal. Transportation networks, communication networks, and natural environmental should be designed in the way to stimulate the kind of life we would like to live (Do we know for sure?). The goal of developing an anthropopolis is to make all human activities, i.e., where we work, where we live and shop; and where we go to entertain ourselves, as enjoyable as we can. The telecommunication and computer technologies have played an increasingly important roles in all these activities, and yet we are not sure to what extent they are substitutive, complementary or synergistic to traditional means of conducting these activities.
With these three interrelated metropolis in mind, we should make concerted research efforts on the optimal urban forms for the cities in the next millennium. Do we want the relentless urban sprawl to continue, as facilitated by the development of new transportation, communication, and information technologies? Or should we go back to a more compact pedestrian-oriented urban forms as proposed by some leading urban planners in order to better fulfill the ideal sense of community, sustainability, and social equity?

1.2 Urban Processes: The processes contributing to the formations of urban forms are extraordinarily complex, and numerous different theoretical perspectives have been developed during the past two decades to explain these diverse urban processes. I believe that the new urban process theory should take a more holistic approach to synthesize these diverse approaches. The hierarchical theory I am proposing can be broken down into the following three levels:

A. Micro level processes: This is the individual level process using a behavioral approach from theories and concepts of neo-classical economics. Most traditional urban modeling efforts follow into this category.

B. Meso level processes: At this intermediate level, attentions should be paid to the roles and behaviors of various institutions in both private and public sectors. We need to examine how various institutions have shaped urban development trajectory and thus result in different urban forms.

C. Macro level processes: At this level, we should bring the general societal trends into consideration, putting urban development into perspectives of political economy, economic transformation, long wave rhythms, and world systems.

1.3: Urban Policies: I believe the future policy goals should strive to achieve balance of the following objectives:

A. Economic Efficiency: To develop policies to intervene at the individual, institutional, and societal levels to make the technopolis the most economically efficient at both the intra and inter-urban levels to facilitate the flows of goods, people, and information.

B. Environmental Sustainability: To develop policies to intervene at the individual, institutional, and societal levels to make the ecumenopolis the most environmentally sustainable, with plenty of safe water, clean air, and diversified natural habitat.

C. Social Equity: To develop policies to intervene at the individual, institutional, and societal levels to make the anthropopolis truly socially equitable so that the metropolis will become a city for everybody, with equal access to all different kinds of information and services and equal share of environmental burdens.

2. Comments on the three conference themes

2.1. Spatial Technologies and Accessibility
If spatial technologies, as defined in the call for papers for this conference, include new transportation networks, comunication, and information technologies, then the concept of accessibility needs to be redefined both conceptually and operationally. Presently, most measures of accessibility are distance-based, exclusively for the transportation networks. With ubiquitous availability of various communication and information technologies, traditional measures of accessibility may no longer apply. Because of the complexities in the spatial configurations of the new communication and information technology, the accessibility has become more elusive and fluid; thus it would be very difficult, if not impossible, to measure. We need new concepts and measurements to describe the spatial effects of new communication and information technology.

The second point I want to make is: we need to define access to what? Traditionally, we are concerned with access to jobs and services, now more with information. How should we measure people's access to information and to extent the access to information is measurable? We also need to differentiate the physical accessibility (via physical transportation/comunication networks) vs. social accessibility (via various institutional and interpersonal networks). Recent works in the social science literature has revealed that physical accessibility won't succeed unless it is hooked to the right social networks.

The conjectured changes in urban accessibility brought about by the increasingly widespread use of communication and information technologies in the literature remain to be speculations without a sound conceptual justification, not to mention about the urban land use changes at different geographic scales in response to the changes in access brought about by modern spatial technologies. Empirical studies are also lacking in examining the relationships between transportation and communication, to what extent they are substitutive, complementary, or synergistic in affecting the new urban development? The first step to achieve a satisfactory answer to these questions is to conduct an inventory of communication and information infrastructure. We have detailed road maps, but we do not have a thorough knowledge on the telecommunication/information network maps. Maybe we need a project Alexandria II to map out the distribution of various telecommunication and computer networks. Without a complete inventory of telecommunication and information infrastructures, our knowledge of accessibility will remain to be partial and speculative.

2.2 Accessibility and the Truly Disadvantaged
It is common knowledge now that the emerging information society is witnessing an increasing polarization between the haves and the have-nots, and the information-rich and the information-poor. Geographically, those disadvantaged population are predominantly trapped in inner cities and various suburban pocket locations. But the formation of the new underclass or the truly disadvantaged is a complex process. Lack of accessibility is one factor, but some social science studies have revealed that the formation of urban underclass is more than an accessibility issue. At the this moment, we do not know to what extent the accessibility has contributed to their status compared to other factors, such as education, segregation, and discrimination, etc. Some recent empirical work indicated that more access to information may not necessarily mean a better life for them, which should prompt us to consider both positive and negative effects of information on the lives of urban residents.

2.3. GIS and the modeling of new cities
With the recognition that GIS technology so far is more successful as a data inventory and information management tool rather as a spatial analytical and modeling tool, the GIS community, in collaboration with quantitative geographers, regional scientists, and modelers from various substantive fields, has made concerted efforts to integrate GIS with sophisticated analytical and modeling techniques. Numerous technical breakthroughs have been accomplished during the past five years. However, as far as the GIS-based urban modeling is concerned, I would say that GIS remains to be an improved means for unimproved ends. The models that have been implemented using GIS are conceptually still those developed during the 60s and 70s, i.e. various modified versions of Lowry-Garin model, shift-share analysis, mathematical programming techniques, etc. Although they may be useful under certain circumstances, few, if any, has confessed the cardinal sins of those urban models and discussed ways to reconceptualize them to capture the new dynamics of urban reality. Simply implementing a Lowry model using ARC/INFO doesn't add any substance to the model itself.

Undoubtedly, GIS will continue to play a very important role in modeling the new cities and stimulate new representations of urban reality. New urban realities demand new urban conceptual models. Maybe the outline I presented in this note can serve as a guideline for the design of new urban models: to incorporate the processes at the individual, institutional, and societal levels to achieve the goals of economic efficiency, environmental Sustainability, and social equity for metropolis of 21st century in which the technopolis, ecumonopolis, and anthropopolis are syngergistically and artfully integrated.
Last, but not least, I would like to emphasize that our future research efforts be tied more closely to urban policies. There are have been growing disparity between what we purport to describe and manipulate using sophisticated theoretical and methodological frameworks in virtual reality and our ability to say anything really meaningful about what actually happens in urban reality. Just as Gunnar Olsson put it so aptly 20 years ago: "what the analysis yielded was not more knowledge of the phenomena the model was speaking about: what it revealed was instead the hidden structure the model was speaking within." The new research agenda must strike a balance between the sophistication of our techniques/methods and the real world phenomena we are talking about. We need new frameworks, new models, new concepts, but we must strive to translate these new structures and models into meaningful policies and languages that society can appreciate and understand. Rigorous conceptual frameworks should be coupled with meticulous empirical analysis and realistic policy implications. Otherwise, our research efforts may become another self-indulging academic exercise.