You receive a Python module that processes geospatial datasets (CSV/GeoJSON) to compute distances, cluster nearby points, and write summaries. Perform a code review: identify correctness bugs, numerical issues, and edge cases (CRS mismatches, missing/invalid coordinates). Propose performance improvements (vectorization, spatial indexing such as R-tree, batching I/O), refactorings (modularization, type hints, docstrings), and security considerations (input validation, dependency pinning). Outline unit/integration tests with fixture data, estimate time/space complexity of critical paths, and suggest library choices (e.g., pandas, shapely, pyproj) with trade-offs.