Fluid Borders: Rethinking Historical Geography and Fixed Map Boundaries in Contested Regions

This article introduces a quantitative methodology for analyzing contested map borders. The article applies the new analytical technique to a data set of thirty maps showing Bulgaria in ca. 800 CE, a disputed state and period in medieval historiography with relevance to modern national politics and territorial claims. Based on the data set, we generate a series of new maps that make explicit the fluid medieval boundaries and general disagreement among geographers and historiographers. Our analysis begins with a simple point-in-polygon procedure to create a majority map that depicts the points included within the borders of the Bulgarian polity in sixteen or more of the maps (>50 percent). The majority map is then combined with percentage maps, confidence interval map boundaries, and cluster maps. The confidence interval maps are created via a spatial bootstrapping procedure and measure the uncertainty in the majority map. The cluster maps are developed via a radial basis function and provide insight into the potential affectivity based on the cartographers' countries of origin. The final map reflects the general modern consensus of the borders of the Bulgarian polity around 800 CE. Besides its quantitative contribution to medieval and modern cartographic, historiographical, and political debates, this article has developed a widely applicable methodology for synthesizing map borders and territories in cases of cartographic disagreement.

本文提出一套用于解析争议性地图边界的量化研究方法。本文将该新型分析技术应用于一组包含三十张公元800年左右（ca. 800 CE）保加利亚政权疆域的地图数据集——该政权与这一历史时期在中世纪史学界存在争议，且与现代国家政治及领土主张密切相关。基于该数据集，我们生成了一系列新地图，直观展现了中世纪疆域的流动性，以及地理学家与史学家之间普遍存在的观点分歧。本研究的分析首先采用简单的点在多边形内检测算法，生成一张多数共识地图，该地图标注了在16张及以上地图（占比超50%）中均被纳入保加利亚政权疆域边界内的点位。随后，该多数共识地图将与占比地图、置信区间边界地图以及聚类地图相结合。置信区间边界地图通过空间Bootstrap法生成，用于量化多数共识地图中的不确定性。聚类地图通过径向基函数构建，可基于制图者的来源国分析其潜在认知偏向。最终生成的地图则反映了当前学界对公元800年左右保加利亚政权疆域边界的普遍共识。除了为中世纪与现代的地图学、史学及政治辩论提供量化研究支撑外，本文还提出了一套可广泛应用的研究方法，用于在地图绘制存在分歧的场景下整合各类地图边界与疆域数据。