Geodesic vs. Planar Geometries

Page Summary

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• Earth Engine geometries are either geodesic (shortest path on a sphere) or planar (shortest path in a 2-D plane).

• By default, Earth Engine geometry constructors create geodesic geometries, which are suitable for global data.

• Planar geometries can be created by setting the geodesic parameter to false in the constructor.

• You can convert between geodesic and planar geometries using the ee.Geometry constructor.

A geometry created in Earth Engine is either geodesic (i.e. edges are the shortest path on the surface of a sphere) or planar (i.e. edges are the shortest path in a 2-D Cartesian plane). No one planar coordinate system is suitable for global collections of features, so Earth Engine's geometry constructors build geodesic geometries by default. To make a planar geometry, constructors have a geodesic parameter that can be set to false:

 var 
  
 planarPolygon 
  
 = 
  
 ee 
 . 
 Geometry 
 ( 
 polygon 
 , 
  
 null 
 , 
  
 false 
 ); 

Figure 1 shows the difference between the default geodesic polygon and the result of converting the polygon to a planar representation.

You can convert between geodesic and planar geometries using the ee.Geometry constructor.