Google Earth Engine——USGS National Elevation Dataset 國家高程資料集（NED）曾經是*美國地質調查局的主要高程資料産品。NED是一個無縫資料集

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.

國家高程資料集（NED）曾經是*美國地質調查局的主要高程資料産品。NED是一個無縫資料集，包含了美國本土、阿拉斯加部分地區、夏威夷和一些領土島嶼的最佳可用光栅高程資料。NED來自不同的源資料，這些資料被處理成一個共同的坐标系統和垂直測量機關。NED的資料是按照1983年的北美基準（NAD 83）釋出的。所有的高程值以米為機關，在美國本土，以1988年的北美垂直基準（NAVD 88）為參考。在其他地區，垂直參考會有所不同。

*15年來，NED是美國地質調查局國家地圖的主要高程資料産品。然而，在三維高程計劃開始運作後，它已被重新命名，現在被認為隻是國家地圖中的一個高程組成部分。

Dataset Availability

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

Dataset Provider

​​United States Geological Survey​​

Collection Snippet

Copied

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​ee.Image("USGS/NED")​

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Bands Table

Name	Description	Min*	Max*	Resolution	Units
elevation	Elevation	-85.61	4414.22	10.2 meters	Meters

* = Values are estimated

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');