From Island of Hills to Cartesian Flatland? Using GIS to Assess Topographical Change in New York City, 1819–1999

Abstract

Historical geographic information systems (GIS) scholarship has provided important insights into a broad spectrum of historical questions in recent years. This article contributes to the emerging field of historical GIS by employing map algebra and transect analysis to quantitatively assess topographical change resulting from rapid urban growth in New York City since the first quarter of the nineteenth century. These methodological techniques enable a systematic comparison of Manhattan's historical and contemporary topography through a spatial analysis of various topographic metrics, including the extent of positive and negative elevation change, shifts in elevation range, the percentage of geographic area that experienced elevation changes, and the estimated volume of Earth added to and removed from particular areas within the study site. The results indicate that there were more valleys filled than hills leveled on Manhattan's East Side, whereas the reverse was the case on the West Side. The West Side, however, experienced considerably more topographic changes than its eastern counterpart, in large part due to the former's more rugged terrain. Overall, the evidence suggests that although Manhattan's topography has been radically transformed in certain respects, the broader spatial pattern of topographic variation has remained largely constant. These findings, therefore, can be used to support competing narrative claims concerning the significance of the topographical transformations that resulted from the urbanization process in New York City.

En años recientes, el conocimiento relativo a los sistemas de información geográfica (SIG) históricos ha proporcionado importantes visiones dentro del amplio espectro de las cuestiones históricas. Este artículo es un aporte al campo emergente de los SIG históricos mediante el uso de álgebra cartográfica y el análisis de transectos, para evaluar cuantitativamente los cambios topográficos que resultan del rápido crecimiento urbano de la ciudad de Nueva York desde el primer cuarto del siglo XIX. Estas técnicas metodológicas permiten la comparación sistemática de la topografía histórica y contemporánea de Manhattan a través de un análisis espacial de varias métricas topográficas, incluyendo la amplitud del cambio de elevación positiva y negativa, los cambios en el ámbito de la elevación, porcentaje de área geográfica que experimenta cambios de elevación y el volumen estimado de tierra agregada y removida de áreas particulares dentro del sitio de estudio. Los resultados indican que hubo más valles rellenados que colinas obliteradas en el East Side de Manhattan, mientras lo contrario se registró en el West Side. Este segundo lado, sin embargo, experimentó muchos más cambios topográficos que su contraparte oriental, en gran medida debido a la mayor escabrosidad de su terreno. En términos generales, la evidencia sugiere que aunque la topografía de Manhattan ha sido radicalmente transformada en ciertos respectos, el patrón espacial principal de variaciones topográficas ha permanecido muy constante. Estos descubrimientos, por lo tanto, pueden utilizarse en apoyo de narrativas de reclamos competitivos en relación con la significación de las transformaciones topográficas que resultaron del proceso de urbanización de la ciudad de Nueva York.

Key Words:

• historical GIS
• historical topographic reconstruction
• New York City
• topographical history
• urban planning history

关键词:

• 历史地理
• 历史地形重建
• 纽约市
• 地形史
• 城市规划史

Palabras clave:

• SIG históricos
• reconstrucción histórica de la topografía
• ciudad de Nueva York
• topografía histórica
• historia de la planificación urbana

Acknowledgments

REUBEN ROSE-REDWOOD is an Assistant Professor in the Department of Geography at the University of Victoria, P.O. Box 3060 STN CSC, Victoria, BC, Canada, V8W 3R4. E-mail: [email protected]. His research interests focus on the spatial histories of toponymic inscription, genealogies of the grid, and the historical geography of New York City.

LI LI is a PhD candidate in the Department of Geography at Texas A&M University, 810 O&M Building, College Station, TX 77843. E-mail: [email protected]. Her research interests focus on the applications of spatial analysis techniques to urban geography.

Notes

*The authors would like to thank the editor, Sharmistha Bagchi-Sen, and the anonymous peer reviewers for their helpful suggestions to improve the quality of this article. The initial funding to support this research was provided by the Environmental Protection Agency's Science to Achieve Results (STAR) Graduate Fellowship Program.

1. One recent example of the use of GIS to challenge historical orthodoxy is Cunfer's (2008) compelling reassessment of the Dust Bowl, which has often been portrayed as a result of the unsustainable practices of commercial agriculture (e.g., Worster 1979). Although not denying the impact of profit-driven farming on the Great Plains, Cunfer conducted a spatio-temporal analysis of environmental conditions in the region, which indicated that “dust storms are a normal part of southern plains ecology, occurring whenever there are extended dry periods.” He therefore concluded that while the “plowing of crops” can increase the likelihood of dust storms, such practices were not “the sole and simple cause of the Dust Bowl” (Cunfer 2008, 118). Other examples of historical GIS scholarship calling into question historical explanations can be found in the recent collection, Placing History: How Maps, Spatial Data, and GIS Are Changing Historical Scholarship (Knowles 2008a).

2. Technically, the West Side refers to the entire area west of Fifth Avenue, but for the purposes of this study, the West Side designates the area that lies to the west of Eighth Avenue (Central Park West), because the area between Fifth and Eighth Avenues has been omitted from our subscale analysis given the lack of historical data in this portion of the study site.

3. Sanderson (2009) maintains that his research team has been able to extract more than 5,000 elevation measurements from the Randel survey fieldbooks at the New York Historical Society, yet they do not specify the method used to “unscramble Randel's trigonometry enough to translate the oddly transcribed angles into vertical measurements” (Sanderson 2009, 77–78). If Randel's calculations in his survey notes can be systematically converted into elevation values and linked to distinct locations on the Farm Maps (which remains to be seen), this will indeed offer a more comprehensive dataset with which to model Manhattan's historical topography circa 1819. Claiming that such a model also represents the topographic conditions of the year 1609, however, as Sanderson suggested, remains highly questionable.