NASADEM is a reprocessing of STRM data, with improved accuracy by incorporating auxiliary data from ASTER GDEM, ICESat GLAS, and PRISM datasets.

The most significant processing improvements involve void reduction through improved phase unwrapping and using ICESat GLAS data for control.

Documentation:

NASA DEM是对STRM数据的再处理，通过纳入ASTER GDEM、ICESat GLAS和PRISM数据集的辅助数据，提高了精度。

最重要的处理改进涉及通过改进相位解包和使用ICESat GLAS数据进行控制来减少空隙。

Dataset Availability

2000-02-11T00:00:00 - 2000-02-22T00:00:00

Dataset Provider

​​NASA / USGS / JPL-Caltech​​

Collection Snippet

​​ee.Image("NASA/NASADEM_HGT/001")​​

Bands Table

Name

Description

Min

Max

Resolution

Units

elevation

Integer heights in the merged void-free DEM files are relative to the EGM96 geoid (whereas the floating-point heights in the SRTM-only DEM files are relative to the WGS84 ellipsoid).

30 meters

Meters

num

Index indicating the data source and the number of source scenes. * 0: Water in corrected SRTM water body data * 1-23: SRTM 1-23 (max known is 23) * 41-94: PRISM 1-50 (54 max polar, 37 max elsewhere) * 110-160: GDEM3 (saturated at 50) * 170-220: GDEM2 (saturated at 50) * 231: SRTMv3 from GDEM3 * 232: SRTMv2 from GDEM3 * 233: SRTMv2 from GDEM2 * 234: SRTM-with-NGA-fill from GDEM2 * 241: NED from GDEM2 (USA) * 242: NED from GDEM3 (USA) * 243: CDED from GDEM2 (Canada) * 244: CDED from GDEM3 (Canada) * 245: Alaska from GDEM2 (Alaska) * 246: Alaska from GDEM3 (Alaska) * 250: Interpolation * 251: Quad edge averaged where two neighboring quads disagreed (generally a GDEM error) * 255: ERROR (if NUM IS MISSING - none known to exist)

0

255

30 meters

Class

swb

Updated SRTM water body data * 0: Land * 255: Water

0

255

30 meters

Class

* = Values are estimated

数据引用：

NASA JPL (2020). NASADEM Merged DEM Global 1 arc second V001 [Data set]. NASA EOSDIS Land Processes DAAC. Accessed 2020-12-30 from ​​LP DAAC - NASADEM_HGT​​

代码：

var dataset = ee.Image('NASA/NASADEM_HGT/001');
var elevation = dataset.select('elevation');

//加一个白色背景图
var background = ee.Image(1);
Map.addLayer(background, {min: 0, max: 1});

//选择最大最小的范围（高程）
var elevationVis = {
  min: 0,
  max: 2000,
};

// 设置高程的显示大小参数
Map.addLayer(elevation.updateMask(elevation.gt(0)), elevationVis, 'Elevation');
Map.setCenter(17.93, 7.71, 2);

Google Earth Engine——NASA DEM是对STRM数据的再处理，通过纳入ASTER GDEM、ICESat GLAS和PRISM数据集的辅助数据，提高了精度_数据