Uses and advantages of satellite imagery

Satellite imagery is an image of the Earth recorded by sensors on satellites (e.g. Landsat, Sentinel, SPOT, IRS, WorldView) in different wavelength bands, usually in digital form.

Uses

• Land use / land cover mapping and change detection.
• Topographic and thematic mapping, DEM generation and urban planning.
• Monitoring of floods, landslides, glaciers, forest fires and drought; damage assessment after earthquakes.
• Selection of sites and routes of roads, canals, dams and pipelines.
• Water resources: rivers, lakes, snow cover and catchment studies.
• Agriculture and forestry: crop condition, yield estimates, and forest cover.
• Environmental monitoring of pollution, erosion and deforestation.

Advantages

1. Covers large and inaccessible areas in one image (wide synoptic view).
2. Repeat coverage at regular intervals allows monitoring of change over time.
3. Multispectral (and thermal / microwave) bands give information beyond what the eye sees.
4. Digital data is easy to process and combine with GIS.
5. Cheaper and faster than aerial or ground survey for large areas.
6. Many images are free or low-cost (Landsat, Sentinel), and the archive provides historical data.
7. Uniform data over political boundaries, and safe over dangerous areas.