几何图形可视化和信息

直观呈现几何图形

如需直观呈现几何图形,请将其添加到地图中。例如:

Code Editor (JavaScript)

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

// Create a planar polygon.
var planarPolygon = ee.Geometry(polygon, null, false);

// Display the polygons by adding them to the map.
Map.centerObject(polygon);
Map.addLayer(polygon, {color: 'FF0000'}, 'geodesic polygon');
Map.addLayer(planarPolygon, {color: '000000'}, 'planar polygon');

如需详细了解可视化,请参阅地图项和 FeatureCollection 可视化

几何图形信息和元数据

如需查看几何图形的相关信息,请输出该几何图形。如需以程序化方式访问这些信息,Earth Engine 提供了多种方法。例如,如需获取之前创建的多边形的相关信息,请使用以下命令:

Code Editor (JavaScript)

print('Polygon printout: ', polygon);

// Print polygon area in square kilometers.
print('Polygon area: ', polygon.area().divide(1000 * 1000));

// Print polygon perimeter length in kilometers.
print('Polygon perimeter: ', polygon.perimeter().divide(1000));

// Print the geometry as a GeoJSON string.
print('Polygon GeoJSON: ', polygon.toGeoJSONString());

// Print the GeoJSON 'type'.
print('Geometry type: ', polygon.type());

// Print the coordinates as lists.
print('Polygon coordinates: ', polygon.coordinates());

// Print whether the geometry is geodesic.
print('Geodesic? ', polygon.geodesic());

请注意,除非指定投影,否则几何图形的周长(或长度)以米为单位,面积以平方米为单位。默认情况下,计算会基于 WGS84 球体执行,计算结果以米或平方米为单位。