Spatial analytics API: server-side clustering, density, spatial joins

[mikemcdougall]

Context

Esri charges separately for Spatial Analyst, Network Analyst, and GeoAnalytics Server. PostGIS already has the analytical power — we just need to expose it as clean API endpoints.

Scope

• Clustering: DBSCAN (ST_ClusterDBSCAN), K-means (ST_ClusterKMeans) as API operations
• Density: server-side kernel density estimation / heatmap generation
• Spatial joins: point-in-polygon enrichment as an API call (join layer A features with layer B polygons)
• Buffer analytics: buffer + dissolve + aggregate as a single operation
• Temporal aggregation: time-series rollups with spatial grouping
• Accessible via GeoServices REST extension endpoints and OGC API Processes
• Results returnable as features or as MVT tiles

Acceptance Criteria

• DBSCAN clustering endpoint returns clustered features with cluster IDs
• Spatial join enriches points with containing polygon attributes
• Buffer analytics returns dissolved/aggregated results
• All operations respect the shared Filter AST for input filtering
• Performance: 100K feature clustering completes in <5s

References

• ADR-0024: Pro tier feature
• PostGIS docs: ST_ClusterDBSCAN, ST_ClusterKMeans