Overture Maps Foundation recently announced the general availability of the Global Entity Reference System (GERS). GERS provides common, open, accessible IDs for geospatial entities like buildings, places, and roads, making data sharing, onboarding, and joining easier.
The Overture Maps Foundation created the Global Entity Reference System (GERS) to combat the "conflation tax," which is the significant cost and effort of integrating fragmented geospatial data from various sources. Launched in June 2025, GERS assigns unique, persistent identifiers (GERS IDs) to real-world entities such as buildings, places, and roads. These IDs function like "fingerprints" for physical entities, enabling straightforward data joining and updates across different datasets without complex spatial matching. GERS is central to Overture's strategy of providing high-quality, open foundational map data and allows for "Extensions" to add richer, use-case specific attributes.
Making Geospatial Data Onboarding Easier
Overture Maps' Global Entity Reference System (GERS) makes geospatial data onboarding much easier by assigning unique, persistent identifiers (GERS IDs) to real-world entities like buildings, places, and roads. This lets developers join disparate datasets using shared GERS IDs, replacing computationally intensive and error-prone spatial matching with simple, unambiguous lookups, drastically reducing data integration time. Rather than a spatial join (which only a few people know how to do), it’s a column join which is common to spreadsheet users.
Geospatial data is challenging due to the high effort (and resulting cost) of integrating fragmented datasets with inconsistent formats, schemas, and naming conventions. Traditional spatial joins are computationally complex and error-prone, compounded by a lack of stable identifiers, the constant changes in the physical world, and limited geospatial expertise among many data teams.
GERS solves these issues by providing open, high-quality, interoperable base map data with stable, standardized identifiers. It serves as the "linchpin" for Overture's interoperability strategy, and helps reduce the conflation tax by ensuring accurate data correlation. Its is unique in that it is open, global, and entity-based, all three of which are necessary for wide adoption. This framework fosters collaboration, allowing competitive companies to build proprietary solutions on a shared, non-differentiating asset, and streamlining data management for continuous updates and innovation.
Introducing Bridge Files
GERS is an ID system designed to make geospatial data interoperability a reality. The system consists of multiple key elements that make it easier for users to onboard. One of these key elements are Bridge Files, which are introduced next.
Bridge Files link GERS identifiers to those used in other mapping systems, including OpenStreetMap or proprietary datasets. This decouples spatial identity from geometry or source-specific attributes, enabling much simpler and more accurate data integration. By providing these links, Bridge Files enhance the interoperability fostered by GERS, helping users connect diverse geospatial information seamlessly.
Overture uses multiple source datasets in its conflation pipeline; for example it currently uses 7 different sources of data for our Buildings Theme. If the same real-world building is present in 3 of these sources, it doesn’t include all 3 representations of the building in our release. Instead, in the conflation pipeline the same GERS ID is assigned to the same building across all sources, but only the building from one of the sources is included in the release. All of the GERS ID are stored to source ID references, including for features that don’t end up in a release, and these published as Bridge Files.
If end users already deploy any of these source datasets, they can easily connect to Overture data and GERS identifiers by using Bridge Files as a join table. Bridge Files also provide insight into Overture’s conflation process since they show the variety of sources that were available for a feature (e.g. a building).
