Abstract:
This paper explores the potential of Geographic Information Systems (GIS) as a method for historical deconstruction and source criticism that can address the limitations of quantitative approaches in contemporary historical research. While quantitative methods in history have lost prominence, especially in light of the New Cultural History's emphasis on power dynamics and the shift towards centering marginalized populations, this paper proposes a novel approach using GIS to analyze quantitative sources in a more critical manner. The method involves layering different sources to reveal and transcend biases inherent in historical data and its creators, thereby offering a nuanced understanding of complex historical formations. The discussion draws on the web map "Land Acquisition and Dispossession: Mapping the Homestead Act, 1863-1912," published by the author together with Robert K. Nelson and Justin Madron in the online historical atlas American Panorama in 2021 as well as the author's Postdoc project on the same theme at Leipzig University's SFB 1199.

Introduction:
Historical research has witnessed a shift away from quantitative approaches, once considered pivotal for representing historical reality on a large scale. The data positivism associated with historical statistics has been criticized for reflecting the perspectives of the entities generating them, such as governments and businesses. The rise of the New Cultural History, with its emphasis on power dynamics and marginalized populations, further challenges the utility of quantitative history. In response, this paper introduces GIS as a method that can transcend the limitations of earlier quantitative approaches by employing a layered approach to historical data.

Background and Rationale:
While the digital humanities and digital history have contributed to a modest revival of statistical methods in history, they still need to fully address the reservations raised against their quantitative predecessors. Also, many digital projects focus on visualizing sources rather than developing new arguments. Quantitative methods, therefore, remain rare in historical studies. This paper advocates for the use of GIS and georeferencing as a means to break with the data positivism of earlier quantitative approaches, providing a framework for historical deconstruction and source criticism.

Methodology:
The paper discusses the application of GIS, specifically using open-source software like QGIS, to layer different historical sources. This method allows researchers to acknowledge and navigate the one-sidedness of certain source groups, providing a historical representation from multiple perspectives. The layering process enables the integration of diverse data sources while recognizing and accounting for inherent biases. The paper emphasizes that, despite the digital nature of GIS, the used data should be approached with the same level of source criticism as traditional historical research.

Case Study:
The primary case study draws on a Postdoc project at Leipzig University's SFB 1199, which investigates the impact of the U.S. Homestead Act of 1862 on Indigenous nations. As with many studies on colonial history, the project encounters an uneven source situation, with limited statistical or other uniform source sets from Indigenous actors. The paper demonstrates how GIS layering can help to address the one-sided source situation. Layering sources such as statistics on homestead land claims, maps of Indigenous land cessions and reservations, and data on frontier clashes between Indigenous nations, U.S. Army personnel, and civilians can help us deconstruct and contextualize these historical data layers. We gain a more critical understanding of the source datasets and their biases while maintaining the source datasets' grand scope and explanatory potential. The methodology promises to combine the critical edge more common to small historical case studies with the large scale and long duration of macro-historical approaches.

Conclusion:
The paper presents examples from the author's research on the intertwinement of homesteading and Indigenous dispossession between the 1860s and the 1910s. It shows that many legal assumptions regarding the nature and timing of the historical process by which Indigenous lands became U.S. government property and only later were opened to white settlement bore little relation to reality. The real process was messier and more violent than a focus on statute books, land statistics, or even a singular focus on frontier violence would suggest. While alone, the different datasets would tell very one-sided stories, their combination creates a framework for a nuanced history on a grand scale. In telling this history, the paper proposes GIS layering as a valuable method for historical deconstruction and source criticism, especially in contexts with limited or biased data. By acknowledging and addressing the one-sidedness of historical sources, GIS potentially allows for a more nuanced understanding of complex historical processes. As the discipline moves away from quantitative approaches, GIS provides a digital method that aligns with the principles of historical source criticism, fostering a more comprehensive and inclusive historical scholarship.