Google Earth Engine——USGS National Elevation Dataset 国家高程数据集（NED）曾经是*美国地质调查局的主要高程数据产品。NED是一个无缝数据集

USGS National Elevation Dataset 1/3 Arc-Second

The National Elevation Dataset (NED) used to be* the primary elevation data product of the USGS. The NED is a seamless dataset with the best available raster elevation data of the conterminous United States, parts of Alaska, Hawaii, and some territorial islands. The NED is derived from diverse source data that are processed to a common coordinate system and unit of vertical measure. NED data are distributed in conformance with the North American Datum of 1983 (NAD 83). All elevation values are in meters and, over the conterminous United States, are referenced to the North American Vertical Datum of 1988 (NAVD 88). The vertical reference will vary in other areas.

*For over 15 years, the NED was the primary elevation data product of the USGS' National Map. However, it has been renamed and now considered just one component of elevation in The National Map after the 3D Elevation Program became operational.

国家高程数据集（NED）曾经是*美国地质调查局的主要高程数据产品。NED是一个无缝数据集，包含了美国本土、阿拉斯加部分地区、夏威夷和一些领土岛屿的最佳可用光栅高程数据。NED来自不同的源数据，这些数据被处理成一个共同的坐标系统和垂直测量单位。NED的数据是按照1983年的北美基准（NAD 83）发布的。所有的高程值以米为单位，在美国本土，以1988年的北美垂直基准（NAVD 88）为参考。在其他地区，垂直参考会有所不同。

*15年来，NED是美国地质调查局国家地图的主要高程数据产品。然而，在三维高程计划开始运作后，它已被重新命名，现在被认为只是国家地图中的一个高程组成部分。

Dataset Availability

2012-02-07T00:00:00 - 2012-02-07T00:00:00

Dataset Provider

United States Geological Survey

Collection Snippet

Copied

ee.Image("USGS/NED")

Bands Table

* = Values are estimated

代码：

var dataset = ee.Image('USGS/NED');
var elevation = dataset.select('elevation');
var elevationVis = {
  min: 0.0,
  max: 4000.0,
  gamma: 1.6,
};
Map.setCenter(-100.55, 40.71, 5);
Map.addLayer(elevation, elevationVis, 'Elevation');