AI-generated Key Takeaways
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Simplifies geometries within a specified error margin, potentially overriding Earth Engine's default error handling.
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The
maxError
argument dictates the allowed deviation of the simplified geometry from the original. -
Using the
simplify
method can result in consistent rendering across zoom levels but might impact performance at lower zoom levels due to reduced simplification. -
The optional
proj
argument allows specifying the projection for the simplified geometry and how the error margin is interpreted.
This overrides the default Earth Engine policy for propagating error margins, so regardless of the geometry accuracy requested from the output, the inputs will be requested with the error margin specified in the arguments to this algorithm. This results in consistent rendering at all zoom levels of a rendered vector map, but at lower zoom levels (i.e. zoomed out), the geometry won't be simplified, which may harm performance.
Usage | Returns |
---|---|
Polygon.simplify(maxError, proj) | Geometry |
Argument | Type | Details |
---|---|---|
this: geometry | Geometry | The geometry to simplify. |
maxError | ErrorMargin | The maximum amount of error by which the result may differ from the input. |
proj | Projection, default: null | If specified, the result will be in this projection. Otherwise it will be in the same projection as the input. If the error margin is in projected units, the margin will be interpreted as units of this projection. |
Examples
Code Editor (JavaScript)
// Define a Polygon object. var polygon = ee.Geometry.Polygon( [[[-122.092, 37.424], [-122.086, 37.418], [-122.079, 37.425], [-122.085, 37.423]]]); // Apply the simplify method to the Polygon object. var polygonSimplify = polygon.simplify({'maxError': 1}); // Print the result to the console. print('polygon.simplify(...) =', polygonSimplify); // Display relevant geometries on the map. Map.setCenter(-122.085, 37.422, 15); Map.addLayer(polygon, {'color': 'black'}, 'Geometry [black]: polygon'); Map.addLayer(polygonSimplify, {'color': 'red'}, 'Result [red]: polygon.simplify');
import ee import geemap.core as geemap
Colab (Python)
# Define a Polygon object. polygon = ee.Geometry.Polygon([[ [-122.092, 37.424], [-122.086, 37.418], [-122.079, 37.425], [-122.085, 37.423], ]]) # Apply the simplify method to the Polygon object. polygon_simplify = polygon.simplify(maxError=1) # Print the result. display('polygon.simplify(...) =', polygon_simplify) # Display relevant geometries on the map. m = geemap.Map() m.set_center(-122.085, 37.422, 15) m.add_layer(polygon, {'color': 'black'}, 'Geometry [black]: polygon') m.add_layer( polygon_simplify, {'color': 'red'}, 'Result [red]: polygon.simplify' ) m