GEE数据集——澳大利亚1987—2022年30米分辨率地表水数据集

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发布于 2024-05-24 09:23:35

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发布于 2024-05-24 09:23:35

简介

澳大利亚数字地球（DEA）水观测使用一种算法将大地遥感卫星图像中的每个像素分为 "湿"、"干 "或 "无效"。水观测统计提供的信息包括每年大地遥感卫星能够清晰观测到某一区域的次数、这些观测结果中潮湿的次数，以及这意味着在地貌中观测到水的时间百分比。

将分类像素合并成涵盖每年的摘要，就能得到通常有水和很少有水的地方的信息。由于没有对该产品进行置信度过滤，它受到输入的水分类中出现的误分类噪音的影响，很难单独进行解释。

该产品是澳大利亚数字地球计划的一部分

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数据介绍

Catalog Owner

Geoscience Australia

Dataset Availability

1987-01-01T00:00:00Z–2022-01-01T00:00:00Z

Dataset Provider

Geoscience Australia NGIS

Contact

https://www.ga.gov.au/contact-us

Earth Engine Snippet

ee.ImageCollection("projects/geoscience-aus-cat/assets/ga_ls_wo_fq_cyear_3")

DEA Water Observations Statistics (Landsat)

Geoscience Australia Landsat Water Observation Statistics Collection 3

Version:

3.1.6 (Latest)

Product types:

Derivative, Raster

Time span:

1986 – Present

Update frequency:

Periodically

Product IDs:

ga_ls_wo_fq_apr_oct_3, ga_ls_wo_fq_nov_mar_3, ga_ls_wo_fq_cyear_3, ga_ls_wo_fq_myear_3

Resolution 25 meters

波段

Name	Max	Wavelength	Description
blue	10000*	0.450-0.520 μm	Band blue surface reflectance geometric median.
green	10000*	0.520-0.600 μm	Band green surface reflectance geometric median.
red	10000*	0.630-0.690 μm	Band red surface reflectance geometric median.
near_infrared	10000*	0.760-0.900 μm	Band near infrared surface reflectance geometric median.
shortwave_infrared_1	10000*	1.550-1.750 μm	Band shortwave infrared 1 surface reflectance geometric median.
shortwave_infrared_2	10000*	2.080-2.350 μm	Band shortwave infrared 2 surface reflectance geometric median.
Euclidean_distance_median_absolute_deviation	10000*		The Median Absolute Deviation using Euclidean distance (EMAD). EMAD is more sensitive to changes in target brightness.
spectral_distance_median_absolute_deviation	10000*		The Median Absolute Deviation using Cosine (spectral) distance (SMAD). SMAD is more sensitive to change in target spectral response.
Bray_Curtis_dissimilarity_median_absolute_deviation	10000*		The Median Absolute Deviation using Bray Curtis dissimilarity (BCMAD). BCMAD is more sensitive to the distribution of the observation values through time.
count	400*		The number of the available pixels used for calculation per calendar year.

* estimated min or max value

代码

var water_obs = ee.ImageCollection('projects/geoscience-aus-cat/assets/ga_ls_wo_fq_cyear_3');

var gray = 150;
var background = ee.Image.rgb(gray, gray, gray).visualize({ min: 0, max: 255 });

var visualization_frequency = {
  bands: ['frequency'],
  min: 0.0,
  max: 1.0,
  palette: ['ffffff', 'ffbbbb', '0000ff']
};

var point = ee.Geometry.Point([113.651455, -26.024137]);

var image = water_obs.filterBounds(point)
                     .filterDate('2010-01-01', '2011-01-01')
                     .first()
                     .visualize(visualization_frequency);
                     
Map.centerObject(image, 12);
var imageWithBackground = ee.ImageCollection([background, image]).mosaic();
Map.addLayer(imageWithBackground, {}, 'Water Frequency ratio');

引用

Mueller, N., Lewis, A., Roberts, D., Ring, S., Melrose, R., Sixsmith, J., Lymburner, L., McIntyre, A., Tan, P., Curnow, S., & Ip, A. (2016). Water observations from space: Mapping surface water from 25 years of Landsat imagery across Australia. Remote Sensing of Environment, 174, 341-352 https://cmi.ga.gov.au/data-products/dea/686/dea-water-observations-statistics-landsat