The Open Geospatial Consortium (OGC) defines a set of core operations that a Discrete Global Grid System (DGGS) must support. These include quantization, spatial relations, and interoperability. Together, they form the foundation for integrating DGGS into spatial data infrastructures and enabling robust geospatial analysis.
Quantization
Quantization is the most fundamental DGGS operation. It enables the transformation of existing geospatial data into a DGGS-compatible format. This process involves:
- Crawling source datasets
- Converting data into internal DGGS formats
- Integrating and aggregating values into grid cells
- Performing quality control checks
The core of quantization lies in converting between geographic coordinates and DGGS cell addresses. Most DGGS-based methodologies include custom or system-supported procedures for this conversion step.
Spatial Relations
DGGS must support spatial relationships at both the cell and object levels.
Cell-Level Relations
These include:
- Sibling relations: adjacent cells at the same resolution
- Parent-child relations: hierarchical connections between cells at different resolutions
Libraries such as DGGRID support these relations. The efficiency of querying depends on the type of indexing used. Hierarchical indexing improves performance for parent-child navigation. Coordinate-based indexing enhances sibling detection and neighborhood queries.
Object-Level Relations
Traditional GIS uses the Dimensionally Extended 9-Intersection Model (DE-9IM) to describe topological relationships. Adapting this to DGGS requires care. Certain relationships, such as “exterior of A intersects interior of B,” may not apply in a DGGS context where data is quantized to discrete cells. A modified or extended model may be needed, especially to represent fuzzy or shared boundaries between complex geographic features.
Interoperability
Interoperability is a high-level requirement for a mature DGGS implementation. A DGGS must support communication with external systems and users through standard APIs and data formats. This ensures compatibility with broader spatial data infrastructures and facilitates data exchange between organizations. Work in this area is ongoing, with efforts focused on defining open standards and supporting integration into geospatial ecosystems.
Supporting these core operations allows DGGS to move beyond theory and into practical applications, serving as a scalable and standards-compliant foundation for modern geospatial systems.