Data Provenance

The Global Ecclesiastical Jurisdictions Version 1.0 dataset was developed by collaborators at GoodLands and the Environmental Systems Research Institute, Inc. (Esri) in 2016. The boundaries were constructed through an extensive process of geographic research, source comparison, digitization, georeferencing, and manual cartographic interpretation. The process drew on many different kinds of materials, including published maps and atlases, ecclesiastical sources, geographic and geopolitical boundary data, jurisdictional information, point locations, historical documents, and maps and materials shared directly by members of the Catholic Church.

The provenance spreadsheet accompanying this version attempts to catalog the principal sources used in developing the boundaries, but it is not a complete record of every source consulted. Additional materials were used for cross-checking, verification, and contextual understanding, including correspondence and phone consultations with clergy and other knowledgeable individuals, older papers and maps shared by priests, and maps encountered during pilgrimages that were photographed, georeferenced, and compared with other sources. Many of these materials were invaluable for resolving local or ambiguous boundaries but were not always available in a form that could be fully documented or cited. The provenance record has therefore become progressively more comprehensive with subsequent versions and improvements to the project's documentation and versioning practices.

The geographic construction of the dataset involved georeferencing a large number 

of historical and contemporary map images, comparing those maps against  corresponding geopolitical boundaries where appropriate, referencing known point locations, and synthesizing information across many independent sources. Where existing jurisdictional data were available, these were also reviewed and cross-checked. In many areas, boundaries ultimately required manual interpretation and digitization based on the available evidence.

The source materials varied considerably in geographic extent, precision, scale, and resolution. To create a globally consistent dataset suitable for geographic analysis, the resulting boundaries were harmonized to a common cartographic scale of approximately 1:3,000,000. This required generalization and spatial adjustment so that the dataset could function as a uniform global analytical layer rather than as a collection of boundaries at incompatible levels of detail. The resulting geometries should therefore be understood as a standardized geographic representation rather than a survey-level or legally precise delineation of ecclesiastical boundaries.

The Version 1.0 dataset represents an unusually broad synthesis of geographic and ecclesiastical information assembled from many sources and through substantial manual research and cartographic work. The provenance record identifies the sources that could be systematically documented, while recognizing the many additional contributions, formal and informal, that helped cross-check and improve the boundaries. We are grateful to the many people who shared maps, documents, local knowledge, and historical materials that contributed to this work.

An important component of the 2016 Diocesan Boundaries of the Catholic Church dataset was the close collaboration with David M. Cheney, creator of Catholic-Hierarchy.org. Cheney had been systematically developing a global database of Catholic bishops and dioceses for many years before this project. His database began in Corel Paradox around 1996–1999, initially to organize information on bishops and dioceses, and was expanded in 2000 to support historical changes to dioceses and the storage of yearly diocesan data.

Cheney's work draws extensively on the Annuario Pontificio and other ecclesiastical sources. His continuing source documentation identifies Annuario Pontificio volumes across more than a century, including extensive holdings from the twentieth and twenty-first centuries. Through our collaboration, Cheney generously shared data from this long-running database and worked closely with the project team to help populate and enrich the geographic diocesan dataset with structured ecclesiastical information.

This collaboration was particularly valuable because Cheney's database contained not only names and basic jurisdictional information, but also historical and statistical information associated with individual dioceses. His meticulous documentation and robust data dictionary provided an important structure for connecting geographic boundaries to the corresponding ecclesiastical entities and their attributes. This made it possible for the geographic dataset to represent dioceses not simply as polygons on a map, but as identifiable ecclesiastical units to which demographic, organizational, historical, and statistical information could be connected.