Model answer

What Landsat is good for — basically watching the Earth’s surface change, decade after decade.

• Forests — tracking deforestation in the Amazon, Borneo, Congo. Map every year, see what’s gone.
• Cities — urban growth, sprawl, paving over farmland.
• Agriculture — crop type maps, yield forecasts (track how green fields get during the season).
• Water — reservoir levels, glacier retreat, algal blooms in the Great Lakes.
• Disasters — wildfire burn scars, flood extent, volcanic activity.
• Climate — long-term surface-temperature trends, snow-cover decline.

Why it works: Landsat has been running since 1972, the imagery has been FREE since 2008, and a single scene covers ~185 km × 170 km. Hard to find a serious land-change study that doesn’t lean on Landsat somewhere.

🔬 Show the science / technical version

• Continuity since 1972 — decadal change detection unmatched by any other system.
• Land-cover / land-use change — Amazon deforestation, urban growth, wetland loss.
• Agriculture — crop-type mapping, yield forecasting via NDVI, irrigation monitoring.
• Water — reservoir extent, glacier retreat, algal blooms (thermal + VSWIR).
• Disaster response — wildfire burn scars, flood extent, volcanic activity.
• Climate — long-term surface-temperature records, snow-cover trends.
• Free & open data policy (since 2008) — the single biggest multiplier of Landsat’s scientific impact.