GeoTools is an open-source Java library for geospatial data manipulation, implementing OGC standards and providing a modular architecture for data access, styling, rendering, and coordinate reference systems. It supports a wide range of vector and raster formats through JDBC plugins (PostGIS, Oracle, SQL Server, etc.), shapefile, GeoPackage, GeoTIFF, NetCDF, and more. The library is used as the foundation for GeoServer and other GIS applications, offering a rich set of filter functions, process framework, and XML binding infrastructure for OGC web services (WMS, WFS, WCS, WPS). The codebase is well-structured with extensive test coverage, though some modules are marked as unsupported and may have lower maintenance priority.
Centerline is a Python library for computing the medial axis (centerline) of polygon geometries using Voronoi diagrams. It provides both a programmatic API via the Centerline class and a command-line interface (create_centerlines) for processing vector files. The library takes polygon/multipolygon inputs, generates a Voronoi diagram from densified boundaries, filters ridges contained within the input geometry, and unions them to produce a multilinestring output while preserving attribute data. The architecture separates core algorithmic logic (geometry.py) from I/O and CLI concerns (converters.py), with proper error handling via custom exceptions.