This repository is a comprehensive Go library for geometric data structures and operations. It provides implementations of OGC-standard geometry types (Point, LineString, Polygon, MultiPoint, MultiLineString, MultiPolygon, GeometryCollection) with support for 2D, 3D, and measured dimensions. The library includes algorithms for computational geometry (area, centroid, convex hull, line intersection, etc.) and encoders/decoders for formats like WKT, WKB, GeoJSON, KML, and IGC. Architecture is modular: core `geom` package defines types and interfaces, `xy`/`xyz` packages handle planar/spatial algorithms, `encoding/*` packages manage format serialization, and utilities like `transform` and `sorting` offer reusable helpers. Command-line tools for IGC parsing and PostGIS integration demonstrate practical usage. The code emphasizes clean separation of concerns, interface-driven design, and thorough testing including property-based and fuzzing tests.