In this bold new approach to computerized spatial analysis of urban form, Benjamin N. Vis develops a taxonomy of boundary line types (BLTs) that are used to define the nature of an inhabited space. The methodology is a clear descendant of Bill Hillier and Julienne Hanson's space syntax (The Social Logic of Space, 1984), striving toward generalized applicability cross-culturally and through time. By focusing on the boundaries that structure a space, considering both their permeability and their bidirectionality, Vis puts forth a compelling framework for investigation of human–environment interactions in an urban setting and for the comparisons that can be made between settlement layouts. For a test case, he compares maps from two distinct urban settings: Winchester, England, as a Western, historically known, historical/contemporary city; and the Maya site of Chunchucmil, as a non-Western, archaeologically known, premodern city.

Following a brief introduction, Chapters 1 through 4 provide wide-ranging theoretical coverage that progresses from overarching urban and spatial theory to a background for boundaries and their significance to a built environment. The chapters lay out the fundamental relationship between the built environment and the social world while highlighting the specific role played by boundaries. In Chapter 5, Vis explicates his Ontology of Boundary Line Types, the BLTs that constitute his system. In total, there are 13 numbered BLTs plus a fourteenth category of Virtual Boundaries. Given that all boundaries are able to be crossed, they serve to facilitate access rather than close it off. This notion is counterintuitive to the casual viewer of a map, and it is a fundamental (and compelling!) element separating this approach from most others, including space syntax. The human–environment interactions covered by actor–network theory (ANT) seem relevant here, and although ANT was discussed and mostly dismissed in Chapter 2, a more thorough discussion of the relationship between the two paradigms would have been appropriate. Otherwise, the reasoning and theoretical justifications behind them are excellent.

The chapters that follow provide a detailed explanation of the BLT system and its implementation. In Chapter 6, this guide is accompanied by a healthy dose of additional theory, especially regarding GIS and space syntax. Chapter 7 then lays out his test case, explaining his reasons for choosing Winchester and Chunchucmil and showing—in a stepwise manner—how he preprocessed the data for each map for BLT analysis. In addition, some rules are laid out as to how the different BLTs interact. The coverage is incomplete, however, and a more comprehensive treatment of how the various types inhere or preclude others seems important for understanding the fundamental structure of the BLT system. Chapter 8 then steps away from that specific case, reverting to a big-picture perspective that strikes the reader more as an enumeration of present limitations of BLT mapping and possibilities for future research. Although the information presented is well stated, it is unclear why the chapter is interposed between the test case setup and results. Those results appear as Chapter 9, followed by a short postscript that considers future directions for the methodology.

The implementation of the BLT system in the test case falls short of the established expectations, as Vis admits. The extensive methodological background he provided, and the broad world of possibilities it offers, made that outcome somewhat inevitable. He is nonetheless able to demonstrate a number of the strengths of the approach and to highlight some of the challenges in making historical and archaeological maps directly comparable. I have one brief suggestion for future implementation. The overwhelming task of finding patterns across an entire urban space and pulling output data from the whole of the map moves away from the human-scale experience. Perhaps an object-oriented GIS that stochastically moves through the BLT map and provides path-specific data can be run iteratively. Such an approach can focus on regions of interest within the general map and show, via the boundaries encountered and crossed, the possibilities of individual movement. These data can then be aggregated to provide insight into settlement-wide patterns.

In this volume, Vis has done an admirable job developing a new and useful avenue for robust comparison of spatial data. Rendering the distinction between modern/contemporary and premodern as irrelevant to the analysis is perhaps its greatest strength, fitting with its broader aim of moving past the need for preestablished categories. In their current form, the methods are time consuming, and it remains to be seen how intuitive the outputs of the analyses can be for nonspecialists. The fundamentals of the system are solid, though, and they should lend themselves to a wide array of applications as they are further developed toward specific ends. I applaud the constructive relationship developed between Vis and the Pakbeh Regional Economy Program, run by Scott Hutson, which allowed Vis to use the Chunchucmil map. Such relationships and data sharing should be encouraged and expanded. As spatial data becomes ever more expansive and granular in its coverage, frameworks like the one developed here by Vis will serve to pull forth the human element from the forms that are uncovered, offering a firmly anchored approach to spatial exploration and interpretation.