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Understanding GERS IDs

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Understanding GERS IDs

The Global Entity Reference System (GERS) provides a standardized framework for identifying and referencing geospatial entities. This page explains what GERS IDs are, why they matter, and how GEM leverages them to transform your geospatial data management.

What is a GERS ID?

A GERS ID (Global Entity Reference System Identifier) is a unique, persistent identifier assigned to geospatial features such as road segments, intersections, and other map entities. Developed as part of the Overture Maps Foundation initiative, GERS IDs provide a common reference system that enables interoperability across different mapping platforms and data sources.

Key characteristics

Unique

  • Each GERS ID uniquely identifies a specific geospatial entity
  • No two entities share the same identifier
  • Eliminates ambiguity in data references

Persistent

  • IDs remain stable over time, even as map features are updated
  • Enables historical data tracking and analysis
  • Supports long-term data management strategies

Global

  • Consistent identification system across regions and countries
  • Enables worldwide interoperability
  • Supports cross-border applications

Standardized

  • Based on open standards
  • Community-driven development through Overture Maps Foundation
  • Vendor-neutral approach

Why GERS IDs matter

The challenge of geospatial data integration

Organizations working with geospatial data typically face several challenges:

  1. Multiple Data Sources: Different vendors, agencies, and systems use different identification schemes
  2. Data Conflation: Matching and merging overlapping datasets is complex and error-prone
  3. Map Updates: When maps change, maintaining data consistency becomes difficult
  4. Interoperability: Sharing data across systems requires custom integration for each pairing
  5. Historical Tracking: Following features over time as maps evolve is challenging

The GERS solution

GERS IDs address these challenges by providing:

  • Common Language: A shared reference system that all parties can use
  • Reduced Complexity: Eliminate custom integration between each system pair
  • Data Persistence: Track entities consistently across map versions
  • Simplified Maintenance: Reduce effort required to keep data aligned
  • Open Ecosystem: Participate in a growing community of GERS-enabled services

How GERS IDs work

Structure

GERS IDs are structured identifiers that encode information about the geospatial entity they represent. While the specific format may vary by entity type, they typically include:

  • Entity Type: Indicates whether the ID refers to a road, intersection, place, etc.
  • Unique Identifier: A globally unique component
  • Version Information: Tracks changes to the entity over time

Example

1Gers Road ID: R_78212
2- R: Indicates this is a road entity
3- 78212: Unique identifier for this specific road

Entity types

GERS IDs can represent various geospatial entities:

  • Roads: Individual road segments
  • Intersections: Junction points where roads meet
  • Places: Points of interest, addresses, and other locations
  • Administrative Boundaries: Political and administrative divisions
  • Transportation Infrastructure: Bridges, tunnels, and other features

Linear referencing with GERS

One of the most powerful features of GERS IDs is support for linear referencing along road segments.

What is linear referencing?

Linear referencing is a method of describing positions along a linear feature (like a road) using a measurement from a reference point, rather than geographic coordinates.

Example

1Gers Road ID: R_78212
2- Section A: 0-67m, Speed Limit: 30 km/h
3- Section B: 67-142m, Speed Limit: 50 km/h

This allows you to:

  • Reference specific positions along a road
  • Define segments with different attributes
  • Support sub-segment level precision
  • Enable dynamic segmentation

Benefits of linear referencing

  1. Precision: Sub-meter accuracy for positioning data along roads
  2. Flexibility: Dynamically create segments without modifying the base map
  3. Efficiency: Store data more compactly than coordinate-based approaches
  4. Consistency: Maintain references even when road geometry is updated

GERS IDs and map updates

One of the most significant advantages of GERS IDs is how they handle map updates.

Traditional approach (without GERS)

  1. Map provider releases new map version
  2. Your custom road IDs no longer match
  3. Manual conflation required to remap your data
  4. Time-consuming, error-prone process
  5. Data may be temporarily unavailable

With GERS IDs

  1. Map provider releases new map version with updated GERS IDs
  2. GERS system maintains continuity for unchanged features
  3. Changed features receive updated IDs with transition information
  4. Your data automatically stays synchronized
  5. Minimal manual intervention required

Handling changes

GERS handles different types of map changes:

No Change

  • Feature remains the same
  • GERS ID stays constant
  • Your data requires no update

Minor Modification

  • Geometry updated slightly (e.g., improved accuracy)
  • GERS ID typically remains the same
  • Your data automatically benefits from improved geometry

Significant Change

  • Road realigned, split, or merged
  • New GERS ID(s) assigned
  • System provides transition mapping
  • GEM can automatically update your data associations

New Feature

  • New road or feature added
  • New GERS ID assigned
  • Opportunity to extend your data coverage

GEM and GERS integration

GEM makes working with GERS IDs simple and automatic.

Automatic matching

GEM uses AI-driven algorithms to:

  1. Analyze your geospatial datasets
  2. Identify corresponding GERS entities
  3. Assign appropriate GERS IDs
  4. Handle complex matching scenarios
  5. Provide confidence scores for matches

Sub-segment precision

GEM leverages linear referencing to:

  • Match data at sub-segment level precision
  • Support detailed attribution along roads
  • Enable fine-grained analytics
  • Preserve the full detail of your original data

Continuous synchronization

GEM maintains alignment by:

  • Monitoring GERS updates
  • Automatically updating your data associations
  • Handling feature changes intelligently
  • Providing change notifications
  • Maintaining historical links

GERS and the Overture Maps foundation

What is Overture Maps?

The Overture Maps Foundation is a collaborative effort to develop open, interoperable map data. Key aspects include:

  • Open Standard: Freely available specifications
  • Industry Collaboration: Supported by major technology companies
  • Community-Driven: Open to contributions and feedback
  • Interoperable: Designed for cross-platform compatibility

TomTom's role

TomTom is an active participant in the Overture Maps Foundation:

  • Contributing to GERS specification development
  • Providing high-quality map data
  • Supporting the open mapping ecosystem
  • Developing tools like GEM to make GERS accessible

Benefits of using GERS IDs with GEM

Global interoperability

Your data becomes compatible with:

  • Other GERS-enabled systems
  • Overture Maps data
  • TomTom Orbis Maps
  • Future GERS-enabled services

Reduced conflation costs

  • Eliminate manual matching between systems
  • Reduce ongoing maintenance burden
  • Accelerate time-to-market for new integrations
  • Lower total cost of ownership

Higher data quality

  • Leverage standardized, persistent identifiers
  • Benefit from community-validated references
  • Improve data accuracy and consistency
  • Enable better data validation

Future-proof investment

  • Participate in growing open ecosystem
  • Benefit from ongoing GERS improvements
  • Ensure long-term data compatibility
  • Support evolving business needs

Real-world example

Before GERS and GEM

A city traffic department has:

  • Traffic sensors along roads (with internal IDs)
  • Incident reports (with custom location references)
  • Maintenance records (using yet another ID system)
  • Must manually reconcile these systems
  • Struggles to share data with state transportation department

After GERS and GEM

The same city:

  • All systems reference roads using GERS IDs
  • Data automatically aligns across systems
  • Seamlessly shares data with state and other jurisdictions
  • Immediately benefits from map updates
  • Reduces IT maintenance burden significantly

Technical considerations

Data format

GERS IDs can be integrated with various data formats:

  • GeoJSON with GERS ID properties
  • CSV files with GERS ID columns
  • Database tables with GERS ID fields
  • GIS shapefiles with GERS attributes

Working with GERS IDs

Once matched through GEM:

  • Reference features using GERS IDs in your applications
  • Use GERS IDs for data correlation and linkage
  • Maintain GERS IDs for long-term data consistency
  • Enable interoperability with other GERS-enabled systems

Performance

GERS IDs are designed for efficiency:

  • Fast lookup and indexing
  • Compact storage requirements
  • Efficient range queries
  • Scalable to global datasets

Best practices

Implementing GERS IDs

  1. Store Both: Keep original IDs and GERS IDs initially
  2. Validate: Verify GERS ID assignments meet your quality requirements
  3. Monitor: Track GERS ID changes and update patterns
  4. Document: Record your GERS ID integration approach
  5. Test: Validate end-to-end workflows with GERS IDs

Data quality

  1. Source Quality: Ensure your input data is high quality
  2. Match Confidence: Review low-confidence matches
  3. Update Frequency: Establish appropriate sync schedules
  4. Validation Rules: Define acceptance criteria
  5. Exception Handling: Plan for unmatched entities

Frequently asked questions

Q: Are GERS IDs free to use?

A: GERS IDs themselves are part of an open standard. GEM is a commercial service that helps you work with GERS IDs efficiently.

Q: What happens if a road is split into two segments?

A: The original GERS ID may be deprecated, and two new IDs are created. GEM provides transition mapping so your data can be updated accordingly.

Q: Can I use GERS IDs with other maps?

A: Yes, GERS IDs are designed for interoperability across different map providers that support the GERS standard.

Q: How often do GERS IDs change?

A: GERS IDs are designed to be persistent. They change only when the real-world feature changes significantly. Most IDs remain stable across many map releases.

Q: Do GERS IDs work offline?

A: Yes, once you have assigned GERS IDs to your data, they work offline. Online connectivity is needed for initial matching and updates.

Next steps

Ready to leverage GERS IDs for your organization?