AI-generated Key Takeaways
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This Landsat 7 dataset provides annual composites of the Normalized Difference Water Index (NDWI) from 1999 to 2021.
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The NDWI is calculated using top-of-atmosphere reflectance and is sensitive to changes in liquid water content in vegetation.
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This dataset has been superseded by a newer Landsat collection, LANDSAT/COMPOSITES/C02/T1_L2_ANNUAL_NDWI, which is recommended for use instead.
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The data is freely available for research, education, and non-profit use and requires acknowledgement of the USGS as the data source.
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Composites include all scenes from each year, with the most recent pixel representing the composite value for that year.
- Dataset Availability
- 1999-01-01T00:00:00Z–2021-01-01T00:00:00Z
- Dataset Provider
- Tags
Description
These Landsat 7 Collection 1 Tier 1 composites are made from Tier 1 orthorectified scenes, using the computed top-of-atmosphere (TOA) reflectance. See Chander et al. (2009) for details on the TOA computation.
The Normalized Difference Water Index (NDWI) is sensitive to changes in liquid water content of vegetation canopies. It is derived from the Near-IR band and a second IR band, ≈1.24μm when available and the nearest available IR band otherwise. It ranges in value from -1.0 to 1.0. See Gao (1996) for details.
These composites are created from all the scenes in each annual period beginning from the first day of the year and continuing to the last day of the year. All the images from each year are included in the composite, with the most recent pixel as the composite value.
Bands
Bands
| Name | Pixel Size | Description |
|---|---|---|
NDWI |
30 meters | Normalized Difference Water Index |
Terms of Use
Terms of Use
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.