postgis-knowledge-patch_skill

Overview

This skill encapsulates PostGIS 3.5+ changes and new features for writing modern spatial SQL. It highlights breaking changes, new vector/raster/topology functions, and SFCGAL 3D advances so you can update queries, materialized views, and pipelines safely. Use it as a concise reference when targeting PostGIS releases 3.5 through 3.6+ (2024–2026).

How this skill works

The skill summarizes additions and breaking changes by release, focusing on function renames, signature changes, and new capabilities (raster, topology, SFCGAL/3D, coverage and aggregation). It calls out required library versions and examples of semantic shifts you must address in SQL, views, and topology workflows. Use the entries to locate which functions were introduced, replaced, or deprecated and to guide query rewriting and data migration.

When to use it

• Upgrading PostGIS extensions from 3.4 or earlier to 3.5/3.6
• Rewriting queries that use SFCGAL 3D functions or ST_* SFCGAL names
• Adjusting materialized views after changed function signatures (ST_AsGeoJSON, ST_GeneratePoints, ST_Clip)
• Converting topology or raster pipelines affected by bigint IDs, new precision rules, or ST_Clip touched semantics
• Implementing new raster aggregation, exact reclassification, or coverage-cleaning workflows

Best practices

• Audit and rebuild materialized views when function signatures changed (ST_AsGeoJSON, ST_Clip, ST_GeneratePoints)
• Search and replace renamed SFCGAL ST_* functions to CG_* and test 3D behavior on sample geometries
• When upgrading topology, migrate to bigint IDs and adjust any functions that assumed integer topology IDs
• Regenerate random-seeded outputs (ST_GeneratePoints) and re-evaluate tests that depend on deterministic results
• Validate and test critical spatial predicates after ST_DFullyWithin semantics changes and when using new buffering/partitioning functions

Example use cases

• Replace legacy SFCGAL ST_Buffer3D and visibility calls with CG_Buffer3D and CG_Visibility, then re-check application logic
• Use ST_RemoveSmallParts to clean sliver polygons before topological operations and area calculations
• Apply ST_AsRasterAgg to create raster tiles from vector features for visualization or analysis
• Clip rasters with ST_Clip(..., touched=>true) to include boundary pixels in analysis and export
• Run ValidateTopologyPrecision and MakeTopologyPrecise before importing topologies into systems that require consistent precision