Shapely
Python library for creating, manipulating, and analyzing 2D geometric objects (Point, LineString, Polygon) using the GEOS C engine with vectorized NumPy operations in v2.0.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
No network layer; GEOS C library is well-audited; malformed geometry inputs can cause GEOS crashes in rare cases — validate inputs from untrusted sources
⚡ Reliability
Best When
You need fast, reliable 2D geometric operations in Python and are working with in-memory geometry objects rather than files.
Avoid When
You need to read/write spatial files, handle CRS projections, or perform 3D geometric analysis.
Use Cases
- • Computing intersections, unions, and differences between geographic polygons
- • Testing whether points fall within polygon boundaries for spatial containment queries
- • Buffering geometries to create distance-based zones around features
- • Simplifying complex polygon boundaries to reduce vertex count for performance
- • Vectorized batch operations on large arrays of geometries using NumPy integration (v2.0+)
Not For
- • Reading or writing geospatial file formats like GeoJSON, Shapefile, or GeoPackage (use Fiona or GeoPandas)
- • Coordinate reference system (CRS) transformations or projections (use pyproj or GeoPandas)
- • 3D geometry operations — Shapely is strictly 2D (Z coordinates are stored but ignored in calculations)
Interface
Authentication
Local Python library — no authentication required
Pricing
BSD 3-Clause license. Completely free for commercial and open-source use. GEOS underlying library is LGPL.
Agent Metadata
Known Gotchas
- ⚠ Shapely 2.0 introduced breaking API changes from 1.x — geometry constructors and many functions moved; agents using legacy tutorials will encounter AttributeError
- ⚠ Coordinate order is (x, y) i.e., (longitude, latitude) — agents using (lat, lon) order will produce geometrically incorrect results silently
- ⚠ Invalid geometries (self-intersecting polygons) cause operations to return empty or None results without always raising an exception — always validate with is_valid
- ⚠ Z coordinates are accepted but ignored in all 2D calculations — agents assuming 3D distance calculations will get wrong answers
- ⚠ The shapely.ops module was restructured in 2.0; imports like from shapely.ops import unary_union still work but shapely.unary_union is now preferred
Alternatives
Full Evaluation Report
Detailed scoring breakdown, competitive positioning, security analysis, and improvement recommendations for Shapely.
Scores are editorial opinions as of 2026-03-06.