Google Earth Engine ——Landsat 7 ETM+传感器的大气校正表面反射率数据集

This dataset is the atmospherically corrected surface reflectance from the Landsat 7 ETM+ sensor. These images contain 4 visible and near-infrared (VNIR) bands and 2 short-wave infrared (SWIR) bands processed to orthorectified surface reflectance, and one thermal infrared (TIR) band processed to orthorectified brightness temperature. The VNIR and SWIR bands have a resolution of 30m / pixel. The TIR band, while originally collected with a resolution of 120m / pixel (60m / pixel for Landsat 7) has been resampled using cubic convolution to 30m.

These data have been atmospherically corrected using LEDAPS, and include a cloud, shadow, water and snow mask produced using CFMASK, as well as a per-pixel saturation mask.

Strips of collected data are packaged into overlapping "scenes" covering approximately 170km x 183km using a standardized reference grid.

See also the USGS page on SR QA bands.

SR can only be produced for Landsat assets processed to the L1TP level

Data provider notes:

• SR is not run for a scene with a solar zenith angle greater than 76°.
• Users are cautioned to avoid using SR for data acquired over high latitudes (> 65°).
• The panchromatic band (ETM+ Band 7, OLI Band 8) is not processed to Surface Reflectance.
• Efficacy of SR correction will be likely reduced in areas where atmospheric correction is affected by adverse conditions:

• Hyper-arid or snow-covered regions
• Low sun angle conditions
• Coastal regions where land area is small relative to adjacent water
• Areas with extensive cloud contamination

This product is generated by Google using a Docker image supplied by USGS.

该数据集是Landsat 7 ETM+传感器的大气校正表面反射率。这些图像包含4个可见光和近红外（VNIR）波段和2个短波红外（SWIR）波段，这些波段被处理为正交的表面反射率，还有一个热红外（TIR）波段被处理为正交的亮度温度。VNIR和SWIR波段的分辨率为30米/像素。热红外波段，虽然最初是以120米/像素的分辨率采集的（Landsat 7为60米/像素），但已经用三次卷积法重新取样到30米。

这些数据已经用LEDAPS进行了大气校正，包括用CFMASK制作的云、影、水和雪掩码，以及每个像素的饱和度掩码。

收集的数据条被打包成重叠的 "场景"，使用标准化的参考网格，覆盖大约170公里x183公里。

另见美国地质调查局关于SR质量保证带的网页。

SR只能为处理到L1TP级别的Landsat资产制作。

数据提供者说明。

对于太阳天顶角大于76°的场景，不运行SR。

提醒用户避免对在高纬度地区（>65°）获取的数据使用SR。

全色波段（ETM+波段7，OLI波段8）不处理为表面反射率。

在大气校正受到不利条件影响的地区，SR校正的效果将可能降低。

超干旱或被雪覆盖的地区

低太阳角条件

陆地面积相对于邻近水域较小的沿海地区

有大量云层污染的地区

本产品由谷歌使用USGS提供的Docker图像生成。

Dataset Availability

1999-01-01T00:00:00 - 2021-08-12T00:00:00

Dataset Provider

USGS

Collection Snippet

ee.ImageCollection("LANDSAT/LE07/C01/T1_SR")

Resolution

30 meters

Bands Table

Landsat datasets are federally created data and therefore reside in the public domain and may be used, transferred, or reproduced without copyright restriction.

Acknowledgement or credit of the USGS as data source should be provided by including a line of text citation such as the example shown below.

(Product, Image, Photograph, or Dataset Name) courtesy of the U.S. Geological Survey

Example: Landsat-7 image courtesy of the U.S. Geological Survey

See the USGS Visual Identity System Guidance for further details on proper citation and acknowledgement of USGS products.

代码：

var dataset = ee.ImageCollection('LANDSAT/LE07/C01/T1_32DAY_NDVI')
                  .filterDate('1999-01-01', '2002-12-31');
var colorized = dataset.select('NDVI');
var colorizedVis = {
  min: 0.0,
  max: 1.0,
  palette: [
    'FFFFFF', 'CE7E45', 'DF923D', 'F1B555', 'FCD163', '99B718', '74A901',
    '66A000', '529400', '3E8601', '207401', '056201', '004C00', '023B01',
    '012E01', '011D01', '011301'
  ],
};
Map.setCenter(6.746, 46.529, 6);
Map.addLayer(colorized, colorizedVis, 'Colorized');