Google Earth Engine ——地表水的位置和時間分布30米分辨率（JRC/GSW1_0/GlobalSurfaceWater）資料集

This dataset contains maps of the location and temporal distribution of surface water from 1984 to 2015 and provides statistics on the extent and change of those water surfaces. For more information see the associated journal article: High-resolution mapping of global surface water and its long-term changes (Nature, 2016) and the online Data Users Guide.

These data were generated using 3,066,102 scenes from Landsat 5, 7, and 8 acquired between 16 March 1984 and 10 October 2015. Each pixel was individually classified into water / non-water using an expert system and the results were collated into a monthly history for the entire time period and two epochs (1984-1999, 2000-2015) for change detection.

This mapping layers product consists of 1 image containing 7 bands. It maps different facets of the spatial and temporal distribution of surface water over the last 32 years. Areas where water has never been detected are masked.

該資料集包含1984年至2015年地表水的位置和時間分布圖，并提供這些水面的範圍和變化的統計資料。更多資訊見相關期刊文章。全球地表水及其長期變化的高分辨率地圖（自然，2016）和線上資料使用者指南。

這些資料是使用1984年3月16日至2015年10月10日期間擷取的Landsat 5、7和8的3,066,102個場景生成的。使用專家系統将每個像素單獨分類為水/非水，并将結果整理為整個時間段的月度曆史和兩個紀元（1984-1999年，2000-2015年），用于變化檢測。

該測繪層産品由1張包含7個波段的圖像組成。它描繪了過去32年中地表水的空間和時間分布的不同方面。從未檢測到水的區域被掩蓋了。

Dataset Availability

1984-03-16T00:00:00 - 2015-10-18T00:00:00

Dataset Provider

EC JRC / Google

Collection Snippet

ee.Image("JRC/GSW1_0/GlobalSurfaceWater")

Resolution

30 meters

Bands Table

Name	Description	Min	Max	Units
occurrence	The frequency with which water was present.	100	%
change_abs	Absolute change in occurrence between two epochs: 1984-1999 vs 2000-2015.	-100	100	%
change_norm	Normalized change in occurrence. (epoch1-epoch2)/(epoch1+epoch2) * 100	-100	100	%
seasonality	Number of months water is present.	12
recurrence	The frequency with which water returns from year to year.	100	%
transition	Categorical classification of change between first and last year.
max_extent	Binary image containing 1 anywhere water has ever been detected.
max_extent Bitmask	Bit 0: Flag indicating if water was detected or not 0: Not water 1: Water

Class Table: transition

Value	Color	Color Value	Description
#ffffff	No change
1	#0000ff	Permanent
2	#22b14c	New permanent
3	#d1102d	Lost permanent
4	#99d9ea	Seasonal
5	#b5e61d	New seasonal
6	#e6a1aa	Lost seasonal
7	#ff7f27	Seasonal to permanent
8	#ffc90e	Permanent to seasonal
9	#7f7f7f	Ephemeral permanent
10	#c3c3c3	Ephemeral seasonal

資料說明：

All data here is produced under the Copernicus Programme and is provided free of charge, without restriction of use. For the full license information see the Copernicus Regulation.

Publications, models, and data products that make use of these datasets must include proper acknowledgement, including citing datasets and the journal article as in the following citation.

If you are using the data as a layer in a published map, please include the following attribution text: 'Source: EC JRC/Google'

 引用：

Jean-Francois Pekel, Andrew Cottam, Noel Gorelick, Alan S. Belward, High-resolution mapping of global surface water and its long-term changes. Nature 540, 418-422 (2016). (doi:10.1038/nature20584)

代碼：

var dataset = ee.Image('JRC/GSW1_0/GlobalSurfaceWater');
var occurrence = dataset.select('occurrence');
var occurrenceVis = {
  min: 0.0,
  max: 100.0,
  palette: ['ffffff', 'ffbbbb', '0000ff'],
};
Map.setCenter(59.414, 45.182, 6);
Map.addLayer(occurrence, occurrenceVis, 'Occurrence');