Polygon
Overview
Polygon is a spatial feature in a GIS that represents a closed area defined by a series of connected points, often used to represent land parcels, administrative boundaries, or other area-based features. Polygons consist of an exterior ring and optionally one or more interior rings (holes).
Key Concepts
Exterior ring is the outer boundary of the polygon (counterclockwise winding). Interior ring is a hole within the polygon (clockwise winding). Vertices are the points defining the polygon boundary. Closure means the first and last vertices must be identical. Simple polygon has no self-intersections. Valid polygon follows OGC rules (proper winding, no self-intersection).
Representations
| Format | Example |
|---|---|
| WKT | POLYGON((-74 40, -74 41, -73 41, -73 40, -74 40)) |
| GeoJSON | {"type": "Polygon", "coordinates": [[[-74,40],[-74,41],[-73,41],[-73,40],[-74,40]]]} |
Derived Measurements
- Area: Total enclosed area (sq meters, acres)
- Perimeter: Length of exterior boundary
- Centroid: Geometric center point
- Bounding box: Minimum enclosing rectangle
Appendix
Created: 2025-12-13 | Modified: 2025-12-13