Geometry Overview

  • Earth Engine uses the Geometry type to represent vector data, supporting various shapes like points, lines, and polygons, as defined in the GeoJSON specification.

  • Geometries can be created interactively with the Code Editor tools or programmatically by providing coordinate lists to Geometry constructors.

  • LinearRing geometries are closed shapes where the starting and ending coordinates are the same, unlike LineString geometries.

  • Multi-part geometries, such as MultiPoint or MultiPolygon, can be broken down into individual geometries using the geometries() method.

Earth Engine handles vector data with the Geometry type. The GeoJSON spec describes in detail the type of geometries supported by Earth Engine, including Point (a list of coordinates in some projection), LineString (a list of points), LinearRing (a closed LineString), and Polygon (a list of LinearRings where the first is a shell and subsequent rings are holes). Earth Engine also supports MultiPoint, MultiLineString, and MultiPolygon. The GeoJSON GeometryCollection is also supported, although it has the name MultiGeometry within Earth Engine.

Creating Geometry objects

You can create geometries interactively using the Code Editor geometry tools. See the Earth Engine Code Editor page for more information. To create a Geometry programmatically, provide the constructor with the proper list(s) of coordinates. For example:

Code Editor (JavaScript)

var point = ee.Geometry.Point([1.5, 1.5]);

var lineString = ee.Geometry.LineString(
  [[-35, -10], [35, -10], [35, 10], [-35, 10]]);

var linearRing = ee.Geometry.LinearRing(
  [[-35, -10], [35, -10], [35, 10], [-35, 10], [-35, -10]]);

var rectangle = ee.Geometry.Rectangle([-40, -20, 40, 20]);

var polygon = ee.Geometry.Polygon([
  [[-5, 40], [65, 40], [65, 60], [-5, 60], [-5, 60]]
]);

In the previous examples, note that the distinction between a LineString and a LinearRing is that the LinearRing is “closed” by having the same coordinate at both the start and end of the list.

An individual Geometry may consist of multiple geometries. To break a multi-part Geometry into its constituent geometries, use geometry.geometries(). For example:

Code Editor (JavaScript)

// Create a multi-part feature.
var multiPoint = ee.Geometry.MultiPoint([[-121.68, 39.91], [-97.38, 40.34]]);

// Get the individual geometries as a list.
var geometries = multiPoint.geometries();

// Get each individual geometry from the list and print it.
var pt1 = geometries.get(0);
var pt2 = geometries.get(1);
print('Point 1', pt1);
print('Point 2', pt2);