Geometry: points, paths, and areas
Learn why one location, a route, and a boundary need different geometry even when they use the same coordinates.
Why this matters
A coordinate answers “where is this position?” Geometry answers a larger question: is the thing a single place, a path through places, or an area? That distinction lets software perform different kinds of spatial reasoning.
Learn it
A Point stores one position. A LineString stores an ordered sequence of positions. A Polygon stores one or more closed rings that describe an area. Multi-geometries group several shapes of the same kind. GeometryCollection can contain mixed geometry types. The geometry you choose should match the question you need to answer.
Work through an example
A research station can be a Point. A vessel track can be a LineString. A study area or geofence can be a Polygon. Converting all three into points would throw away information about movement and area.
Point → station
LineString → route or track
Polygon → study area or boundaryPractice
- 1Classify several real things as point, path, or area.
- 2Build each shape in the geometry exercise.
- 3Ask what questions become possible only because you chose the right geometry.
Try it
Point, line, polygon, or collection?
These geometry types answer different spatial questions: where something is, how something moves or connects, and what area something occupies.
One position. Useful for a station, observation, stop, asset, or event.
What to watch for
Do not choose Polygon just because an object looks large on a map. Choose geometry based on what the record means and what spatial operations you need.
Where this takes you
Geometry becomes the basis for GeoJSON, routes, geofences, map layers, spatial rules, and many GIS analyses.