What is shapely-compute?

A skill that exposes commands to create geometries, perform boolean operations, evaluate spatial predicates, compute measurements, apply transformations, and validate geometries using Shapely.

Which geometry types are supported?

Points, lines, polygons, multipoints, multilinestrings, and multipolygons are supported, including polygons with holes.

How do I validate or fix geometries before operations?

Use the validate command to check topology, and apply fix or repair strategies as needed to ensure subsequent operations succeed.

shapely-compute

Scanned

npx machina-cli add skill parcadei/Continuous-Claude-v3/shapely-compute --openclaw

Files (1)

SKILL.md

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Computational Geometry with Shapely

When to Use

Creating geometric shapes (points, lines, polygons)
Boolean operations (intersection, union, difference)
Spatial predicates (contains, intersects, within)
Measurements (area, length, distance, centroid)
Geometry transformations (translate, rotate, scale)
Validating and fixing invalid geometries

Quick Reference

I want to...	Command	Example
Create geometry	`create`	`create polygon --coords "0,0 1,0 1,1 0,1"`
Intersection	`op intersection`	`op intersection --g1 "POLYGON(...)" --g2 "POLYGON(...)"`
Check contains	`pred contains`	`pred contains --g1 "POLYGON(...)" --g2 "POINT(0.5 0.5)"`
Calculate area	`measure area`	`measure area --geom "POLYGON(...)"`
Distance	`distance`	`distance --g1 "POINT(0 0)" --g2 "POINT(3 4)"`
Transform	`transform translate`	`transform translate --geom "..." --params "1,2"`
Validate	`validate`	`validate --geom "POLYGON(...)"`

Commands

create

Create geometric objects from coordinates.

# Point
uv run python scripts/shapely_compute.py create point --coords "1,2"

# Line (2+ points)
uv run python scripts/shapely_compute.py create line --coords "0,0 1,1 2,0"

# Polygon (3+ points, auto-closes)
uv run python scripts/shapely_compute.py create polygon --coords "0,0 1,0 1,1 0,1"

# Polygon with hole
uv run python scripts/shapely_compute.py create polygon --coords "0,0 10,0 10,10 0,10" --holes "2,2 8,2 8,8 2,8"

# MultiPoint
uv run python scripts/shapely_compute.py create multipoint --coords "0,0 1,1 2,2"

# MultiLineString (pipe-separated lines)
uv run python scripts/shapely_compute.py create multilinestring --coords "0,0 1,1|2,2 3,3"

# MultiPolygon (pipe-separated polygons)
uv run python scripts/shapely_compute.py create multipolygon --coords "0,0 1,0 1,1 0,1|2,2 3,2 3,3 2,3"

op (operations)

Boolean geometry operations.

# Intersection of two polygons
uv run python scripts/shapely_compute.py op intersection \
    --g1 "POLYGON((0 0,2 0,2 2,0 2,0 0))" \
    --g2 "POLYGON((1 1,3 1,3 3,1 3,1 1))"

# Union
uv run python scripts/shapely_compute.py op union --g1 "POLYGON(...)" --g2 "POLYGON(...)"

# Difference (g1 - g2)
uv run python scripts/shapely_compute.py op difference --g1 "POLYGON(...)" --g2 "POLYGON(...)"

# Symmetric difference (XOR)
uv run python scripts/shapely_compute.py op symmetric_difference --g1 "..." --g2 "..."

# Buffer (expand/erode)
uv run python scripts/shapely_compute.py op buffer --g1 "POINT(0 0)" --g2 "1.5"

# Convex hull
uv run python scripts/shapely_compute.py op convex_hull --g1 "MULTIPOINT((0 0),(1 1),(0 2),(2 0))"

# Envelope (bounding box)
uv run python scripts/shapely_compute.py op envelope --g1 "POLYGON(...)"

# Simplify (reduce points)
uv run python scripts/shapely_compute.py op simplify --g1 "LINESTRING(...)" --g2 "0.5"

pred (predicates)

Spatial relationship tests (returns boolean).

# Does polygon contain point?
uv run python scripts/shapely_compute.py pred contains \
    --g1 "POLYGON((0 0,2 0,2 2,0 2,0 0))" \
    --g2 "POINT(1 1)"

# Do geometries intersect?
uv run python scripts/shapely_compute.py pred intersects --g1 "..." --g2 "..."

# Is g1 within g2?
uv run python scripts/shapely_compute.py pred within --g1 "POINT(1 1)" --g2 "POLYGON(...)"

# Do geometries touch (share boundary)?
uv run python scripts/shapely_compute.py pred touches --g1 "..." --g2 "..."

# Do geometries cross?
uv run python scripts/shapely_compute.py pred crosses --g1 "LINESTRING(...)" --g2 "LINESTRING(...)"

# Are geometries disjoint (no intersection)?
uv run python scripts/shapely_compute.py pred disjoint --g1 "..." --g2 "..."

# Do geometries overlap?
uv run python scripts/shapely_compute.py pred overlaps --g1 "..." --g2 "..."

# Are geometries equal?
uv run python scripts/shapely_compute.py pred equals --g1 "..." --g2 "..."

# Does g1 cover g2?
uv run python scripts/shapely_compute.py pred covers --g1 "..." --g2 "..."

# Is g1 covered by g2?
uv run python scripts/shapely_compute.py pred covered_by --g1 "..." --g2 "..."

measure

Geometric measurements.

# Area (polygons)
uv run python scripts/shapely_compute.py measure area --geom "POLYGON((0 0,1 0,1 1,0 1,0 0))"

# Length (lines, polygon perimeter)
uv run python scripts/shapely_compute.py measure length --geom "LINESTRING(0 0,3 4)"

# Centroid
uv run python scripts/shapely_compute.py measure centroid --geom "POLYGON((0 0,2 0,2 2,0 2,0 0))"

# Bounds (minx, miny, maxx, maxy)
uv run python scripts/shapely_compute.py measure bounds --geom "POLYGON(...)"

# Exterior ring (polygon only)
uv run python scripts/shapely_compute.py measure exterior_ring --geom "POLYGON(...)"

# All measurements at once
uv run python scripts/shapely_compute.py measure all --geom "POLYGON((0 0,2 0,2 2,0 2,0 0))"

distance

Distance between geometries.

uv run python scripts/shapely_compute.py distance --g1 "POINT(0 0)" --g2 "POINT(3 4)"
# Returns: {"distance": 5.0, "g1_type": "Point", "g2_type": "Point"}

transform

Affine transformations.

# Translate (move)
uv run python scripts/shapely_compute.py transform translate \
    --geom "POLYGON((0 0,1 0,1 1,0 1,0 0))" --params "5,10"
# params: dx,dy or dx,dy,dz

# Rotate (degrees, around centroid by default)
uv run python scripts/shapely_compute.py transform rotate \
    --geom "POLYGON((0 0,1 0,1 1,0 1,0 0))" --params "45"
# params: angle or angle,origin_x,origin_y

# Scale (from centroid by default)
uv run python scripts/shapely_compute.py transform scale \
    --geom "POLYGON((0 0,1 0,1 1,0 1,0 0))" --params "2,2"
# params: sx,sy or sx,sy,origin_x,origin_y

# Skew
uv run python scripts/shapely_compute.py transform skew \
    --geom "POLYGON(...)" --params "15,0"
# params: xs,ys (degrees)

validate / makevalid

Check and fix geometry validity.

# Check if valid
uv run python scripts/shapely_compute.py validate --geom "POLYGON((0 0,1 0,1 1,0 1,0 0))"
# Returns: {"is_valid": true, "type": "Polygon", ...}

# Fix invalid geometry (self-intersecting, etc.)
uv run python scripts/shapely_compute.py makevalid --geom "POLYGON((0 0,2 2,2 0,0 2,0 0))"

coords

Extract coordinates from geometry.

uv run python scripts/shapely_compute.py coords --geom "POLYGON((0 0,1 0,1 1,0 1,0 0))"
# Returns: {"coords": [[0,0],[1,0],[1,1],[0,1],[0,0]], "type": "Polygon"}

fromwkt

Parse WKT and get geometry information.

uv run python scripts/shapely_compute.py fromwkt "POLYGON((0 0,1 0,1 1,0 1,0 0))"
# Returns: {"type": "Polygon", "bounds": [...], "area": 1.0, ...}

Geometry Types

point - Single coordinate (x, y) or (x, y, z)
line/linestring - Sequence of connected points
polygon - Closed shape with optional holes
multipoint, multilinestring, multipolygon - Collections

Input Formats

Coordinates string: "0,0 1,0 1,1 0,1" (space-separated x,y pairs)
WKT: "POLYGON((0 0, 1 0, 1 1, 0 1, 0 0))"

Output Format

All commands return JSON with:

wkt: WKT representation of result geometry
type: Geometry type (Point, LineString, Polygon, etc.)
bounds: (minx, miny, maxx, maxy)
is_valid, is_empty: Validity flags
Measurement-specific fields (area, length, distance, etc.)

Common Use Cases

Use Case	Command
Collision detection	`pred intersects`
Point-in-polygon	`pred contains`
Area calculation	`measure area`
Buffer zones	`op buffer`
Shape combination	`op union`
Shape subtraction	`op difference`
Bounding box	`op envelope` or `measure bounds`
Simplify path	`op simplify`

Related Skills

/math-mode - Full math orchestration (SymPy, Z3)
/math-plot - Visualization with matplotlib

Source

git clone https://github.com/parcadei/Continuous-Claude-v3/blob/main/.claude/skills/shapely-compute/SKILL.mdView on GitHub

Overview

Computational Geometry with Shapely lets you create points, lines, and polygons, perform boolean operations (intersection, union, difference), and evaluate spatial predicates and measurements (area, length, distance, centroid). It also supports geometry transformations and validating/fixing invalid geometries to ensure robust GIS workflows.

How This Skill Works

It wraps Shapely geometry objects and exposes commands like create, op, pred, measure, transform, and validate to manipulate them. Users supply inputs as WKT-like strings, and the toolkit applies standard Shapely methods (e.g., intersection, union, contains, buffer, convex_hull) to produce geometries or numeric results.

When to Use It

Creating geometric shapes (points, lines, polygons)
Performing boolean operations (intersection, union, difference)
Evaluating spatial predicates (contains, intersects, within)
Computing measurements (area, length, distance, centroid)
Transforming geometries (translate, rotate, scale) and validating/fixing invalid geometries

Quick Start

Step 1: Create a polygon with the CLI: uv run python scripts/shapely_compute.py create polygon --coords "0,0 1,0 1,1 0,1"
Step 2: Compute the intersection of two polygons: uv run python scripts/shapely_compute.py op intersection --g1 "POLYGON((0 0,2 0,2 2,0 2,0 0))" --g2 "POLYGON((1 1,3 1,3 3,1 3,1 1))"
Step 3: Measure area of the resulting geometry: uv run python scripts/shapely_compute.py measure area --geom "POLYGON((0 0,2 0,2 2,0 2,0 0))"

Best Practices

Validate input geometries before performing operations to avoid errors
Use consistent coordinate systems and precision to ensure reliable results
Test edge cases with holes, multipoints, and multi-geometries
Store intermediate geometries in variables to reuse in subsequent steps
Prefer immutable operations and clearly name outputs for traceability

Example Use Cases

Calculate the overlapping area between two land parcels to assess shared interest
Buffer a point to create a safety or impact zone around a location
Compute the convex hull of a set of survey points to bound a study area
Validate polygons before importing into a GIS to prevent topology errors
Measure area, length, and centroid for reporting on spatial datasets

Frequently Asked Questions

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