dataset · Global
JRC Global Surface Water Mapping Layers, v1.4
This dataset contains maps of the location and temporal distribution of surface water from 1984 to 2021 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](https://www.nature.com/nature/journal/v540/n7633/full/nature20584.html) (Nature, 2016) and the online [Data Users Guide](https://storage.googleapis.com/global-surface-water/downloads_ancill
Visit source ↗Source details
Licence: proprietary
Evidence quality: 28.1
Listed in gee public catalogue API on 2026-10-16; relevance/value screened (haiku).
Metadata checked: 2026-10-14T13:20:00.000Z
What's in it
- Data offered docs-verified
- occurrence (% of time water present) · change_abs (absolute change between epochs) · change_norm (normalised change) · seasonality (months water present) · recurrence (year-to-year return frequency) · transition (categorical change class) · max_extent (binary water-ever-detected mask)
- Coverage docs-verified
- Global · 1984-03-16 to 2021-12-31 (Landsat scenes); Earth Engine availability 1984-03-16 to 2022-01-01
- Resolution docs-verified
- 30 m pixel size (all bands)
- Formats llm-inferred
- Google Earth Engine image (ee.Image)
- Access docs-verified
- Free to use with proper acknowledgement under Copernicus Programme terms; accessed via Google Earth Engine, which requires registration. Entry metadata lists licence as 'proprietary', which conflicts with the docs.
Useful for
- Use cases llm-inferred
- Flood-risk FRA context: historic surface water occurrence and seasonality at or near a site · BNG/ecology baseline: separating permanent from seasonal water around a development footprint · Catchment screening: long-term change in water extent using change_norm and transition bands
- Audience llm-inferred
- flood risk consultants · hydrologists · ecologists · GIS analysts · planners
Limitations
- Constraints llm-inferred
- Entry licence 'proprietary' conflicts with docs (Copernicus, free with acknowledgement); verify before client use · Earth Engine platform is described as free for research, education and nonprofit use; commercial consultancy terms are not stated · Requires Earth Engine registration; entry auth is null · Occurrence mask double-counts partial occurrence (mask value equals band value), so mask-based statistics may mislead · Areas where water was never detected are masked, so masked pixels are not confirmed dry land · 30 m Landsat resolution may under-represent small or narrow water bodies · Static historical product ending 2021; no newer epochs listed
Evidence
- ee.Image('JRC/GSW1_4/GlobalSurfaceWater')
- https://developers.google.com/earth-engine/datasets/catalog/JRC_GSW1_4_GlobalSurfaceWater
Check upstream coverage, uncertainty and licence before use. Station observations are not forecasts or design levels.