A technical reference for the satellite and gridded data sources the platform draws on — resolution, revisit time, temporal coverage, and the original documentation for each, all accessed via Google Earth Engine's public data catalog.
The longest continuous, consistent optical satellite record available, making it the primary source for multi-decade trend analysis and long-baseline change detection.
Finer spatial detail and more frequent revisit than Landsat, at the cost of a shorter historical record — well suited to recent, fine-grained analysis.
Climate Hazards Group InfraRed Precipitation with Station data — blends satellite-derived rainfall estimates with ground station data for improved accuracy over data-sparse regions.
Shuttle Radar Topography Mission — near-global elevation data from a single 11-day shuttle mission, still the most widely used free global DEM.
Modeled population density (people per pixel), derived from census data disaggregated using satellite-derived settlement layers — used for population-weighted zonal statistics.
Radiance from artificial lighting at night — commonly used as a proxy for urbanization intensity, economic activity, and electrification.
C-band synthetic aperture radar. Because radar penetrates cloud and works day or night, Sentinel-1 is the go-to source for flood extent mapping during monsoon and storm events, when optical sensors are blinded by cloud cover. Backscatter (VV/VH) also responds to surface roughness and soil moisture.
The TROPOspheric Monitoring Instrument measures trace-gas column densities — nitrogen dioxide (NO₂), carbon monoxide (CO), sulphur dioxide, ozone, and more — making it the standard free source for mapping air-quality patterns over cities and industrial regions.
A Landsat-derived record of where surface water has been present over nearly four decades — water occurrence, seasonality, and change. Useful for flood-vulnerability context, reservoir and lake monitoring, and separating permanent from seasonal water bodies.