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Overview

To systematically identify municipal boundary changes across 35 European countries between 2014 and 2024, we combine automated comparisons of geospatial data over time with man- ual verification against legislative sources. Following (Servigne et al., 2000)1, we use geometric properties of polygons and computational geometry algorithms (e.g. checks for closure, inter- sections, and uniqueness) to detect potential boundary changes between t and t + 1. We then verify these changes against legal records to ensure that they correspond to formally adopted administrative reforms.

Methodological Sequence

Acquisition of Geographic Files

For every pair of consecutive years (t and t + 1), we collect vector datasets (e.g., Shapefile, GeoJSON) containing municipal polygons. All files were exclusively retrieved from authorized national repositories, guaranteeing consistent and accurate geometry.

Automated Change Detection

Specialized algorithms compare the polygons for years t and t + 1, classifying three types of transformations:

  • Extinction – a polygon disappears.
  • Emergence – a polygon appears without a prior reference.
  • Reconfiguration – mergers, splits, or boundary adjustments.

The detailed section explains the spatial criteria—minimum-area thresholds, topological adjacency tests, etc.

Automated results are cross-checked against official legislation (laws, decrees, administrative resolutions) to verify:

  1. The category of change nature (see Classification of Municipal Changes)
  2. The accuracy of elements involved (including the number of units involved, names, and dates)

Each detected change is validated and linked to its legal instrument, providing documentary support.

Construction of a relational Database System

These datasets serve as the landing stage of the previous steps and operate under the principle that the history of any municipality’s changes must be reconstructable. The first dataset contains geospatial files in which every municipal polygon is tagged with an internal identifier, making municipalitys’ geographies trackable. The second dataset records the nature and characteristics of changes or stability, detailing how municipalities have evolved. The third contains the legal documentation supporting those changes.

References

  1. Servigne, S., Ubeda, T., Puricelli, A., & Laurini, R. (2000). A methodology for spatial consistency improvement of geographic databases. GeoInformatica, 4(1), 7--24. ↩