Summary
Finding the right place on a map can be tricky when place names mean different things in different contexts. The authors study whether big language models alone can replace traditional lists of place names called gazetteers, which also hold information about locations and relationships. They discover that while language models are good at roughly figuring out places, they often make big mistakes when trying to pinpoint exact locations without the structure gazetteers provide. Adding constraints from gazetteer hierarchies helps with broad location accuracy but doesn't fix all fine-scale errors. This shows that current language model methods still need gazetteers to reliably handle detailed spatial information.
What this means in practice
- •For mapping software developers: Build more accurate place name disambiguation by combining language models with gazetteer-based hierarchical search to reduce location errors in map applications.
- •For geospatial data teams: Improve automated geographic data linking by chaining language model retrievals with spatial hierarchy constraints to enhance coarse geographic grounding in large datasets.
Abstract
Geographic information retrieval (GeoIR) tasks require systems to interpret ambiguous toponyms for downstream applications. Traditionally, toponym resolution relies on gazetteers to provide an explicit index of place entities and spatial relationships. Recently, gazetteer-free approaches seek to reduce dependence on handcrafted searches: dense retrieval utilizes text encoders to capture rich context, moving beyond the limitations of lexical search. However, text encoders implicitly assume that learned representations can function as reliable spatial-semantic indexes. In this paper, we evaluate this assumption through a spatial-semantic indexing setup: given a contextualized toponym mention, we retrieve the corresponding gazetteer entity represented by text derived from a gazetteer knowledge graph. We benchmark five frozen text encoders under two retrieval strategies: brute-force nearest-neighbor retrieval over entity representations, and a neuro-symbolic hierarchical beam search that constrains retrieval (i.e. chaining the search with gazetteer hierarchy). Experimental results reveal a distinct coarse-versus-fine trade-off. Unconstrained dense retrieval frequently incurs catastrophic spatial errors. Conversely, hierarchical constraints improve coarse geographic grounding, but still yield limited benefit for fine-grained localization metrics: vanilla text encoders fail to capture the fine-scale spatial fidelity encoded in gazetteers. Our code is publicly available at: https://doi.org/10.25439/rmt.31094269