Google Earth Engine ——Google Earth Engine ——ALOS World 3D - 30m (AW3D30) 是一个全球数字表面模型 (DSM) V2_1版本数据集

ALOS World 3D - 30m (AW3D30) is a global digital surface model (DSM) dataset with a horizontal resolution of approximately 30 meters (1 arcsec mesh). The dataset is based on the DSM dataset (5-meter mesh version) of the World 3D Topographic Data. More details are available in the dataset documentation.

In the version 2.1, released in April 2018, the source AW3D DSM has been upgraded to version 2. Masks of the land water and low correlation pixels were also filled with existing DEMs in addition to the cloud and snow pixels between 60 degrees North and 60 degrees South. In Japan area, filling was carried out after updating coastline information.

The AW3D DSM elevation is calculated by an image matching process that uses a stereo pair of optical images. Clouds, snow, and ice are automatically identified during processing and applied the mask information. However, mismatched points sometimes remain especially surrounding (or at the edges of) clouds, snow, and ice areas, which cause some height errors in the final DSM. Here are some example areas with data values outside of valid elevation range. Impossibly low negative values are concentrated in Antarctica around (-63.77, -61.660), (-77.22, -150.27), and (-73.29, 168.14); in Indonesia around (-5.36, 134.55); in Brazil around (-1.667113844, -50.6269684); and in Peru around (-10.45048137, -75.39459876) with approximate values of -1013, -998, -635, and -610 respectively. Impossibly high positive values are found in several locations in the Arctic around (79.83, -77.67) and (69.54, -75.42); in Fiji around (-16.58, 179.44) and (-18.96, 178.39); and in Nepal around (28.50, 84.56) with approximate values of 15369, 15213, and 10900 respectively.

ALOS World 3D - 30m (AW3D30) 是一个全球数字表面模型 (DSM) 数据集，水平分辨率约为 30 米（1 弧秒网格）。该数据集基于 World 3D Topographic Data 的 DSM 数据集（5 米网格版本）。数据集文档中提供了更多详细信息。

在 2018 年 4 月发布的 2.1 版本中，源 AW3D DSM 已经升级到版本 2。除了北纬 60 度和 60 度之间的云和雪像素之外，陆地水域和低相关像素的掩码还填充了现有的 DEM度南。日本地区在更新海岸线信息后进行填充。

AW3D DSM 高程是通过使用一对立体光学图像的图像匹配过程计算出来的。云、雪和冰在处理过程中自动识别并应用蒙版信息。然而，不匹配的点有时会特别存在于云、雪和冰区周围（或边缘），这会导致最终 DSM 中出现一些高度错误。以下是一些数据值超出有效海拔范围的示例区域。极低的负值集中在南极洲 (-63.77, -61.660)、(-77.22, -150.27) 和 (-73.29, 168.14) 附近；在印度尼西亚附近 (-5.36, 134.55)；在巴西附近 (-1.667113844, -50.6269684);在秘鲁 (-10.45048137, -75.39459876) 附近，近似值分别为 -1013、-998、-635 和 -610。在北极的几个位置（79.83，-77.67）和（69.54，-75.42）附近发现了不可能的高正值；在斐济大约 (-16.58, 179.44) 和 (-18.96, 178.39)；在尼泊尔 (28.50, 84.56) 附近，近似值分别为 15369、15213 和 10900。

Dataset Availability

2006-01-24T00:00:00 - 2011-05-12T00:00:00

Dataset Provider

JAXA Earth Observation Research Center

Collection Snippet

ee.Image("JAXA/ALOS/AW3D30/V2_1")

Resolution

30 meters

Bands Table

• Bits 0-3: Generated from resampled DSM.
  • 0: Valid
  • 1: Cloud and snow mask (invalid).
  • 2: Land water and low correlation mask (valid).
  • 3: Sea mask (valid).
  • 4: Void filled with National Land Numerical Information 10m DEM by Geographical Survey Institute of Japan (valid).
  • 8: Void filled with Shuttle Radar Topography Mission SRTM-1 Version 3 (valid).
  • 12: Void filled with PRISM DSM (valid).

* = Values are estimated

数据引用说明：

This dataset is available to use with no charge under the conditions specified in the Terms of use for ALOS Global Digital Surface Model.

T. Tadono, H. Ishida, F. Oda, S. Naito, K. Minakawa, H. Iwamoto : Precise Global DEM Generation By ALOS PRISM, ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol.II-4, pp.71-76, 2014. PDF file

J. Takaku, T. Tadono, K. Tsutsui : Generation of High Resolution Global DSM from ALOS PRISM, The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol. XL-4, pp.243-248, ISPRS, 2014. PDF file

J. Takaku, T. Tadono, K. Tsutsui, M. Ichikawa : Validation of ‘AW3D’ Global DSM Generated from ALOS PRISM, ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol.III-4, pp.25-31, 2016. PDF file

T. Tadono, H. Nagai, H. Ishida, F. Oda, S. Naito, K. Minakawa, H. Iwamoto : Initial Validation of the 30 m-mesh Global Digital Surface Model Generated by ALOS PRISM, The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, ISPRS, Vol. XLI-B4, pp.157-162, 2016. PDF file

代码：

var dataset = ee.Image('JAXA/ALOS/AW3D30/V2_1');
var elevation = dataset.select('AVE_DSM');
var elevationVis = {
  min: 0.0,
  max: 4000.0,
  palette: ['0000ff', '00ffff', 'ffff00', 'ff0000', 'ffffff'],
};
Map.setCenter(136.85, 37.37, 4);
Map.addLayer(elevation, elevationVis, 'Elevation');