Earth observation and remote sensing
Earth observation and remote sensing gather information about the Earth's surface and atmosphere from airborne and spaceborne sensors. They provide consistent, repeatable measurements over areas that are hard to monitor on the ground. Space and Earth Observation stewards this page for the Nexus Consortium.
- Institution
- The Global Centre for Risk and Innovation (GCRI)
- Service level
- R0: information and enquiries
Earth observation run
GCRI · Earth observation and remote… · Run R-7626
Acquisition
revisit and swath
Accuracy assessment
stratified sample
| Water | 91 | 97 | 149 |
| Cropland | 85 | 75 | 238 |
| Built-up | 95 | 94 | 137 |
| Forest | 93 | 92 | 124 |
Processing chain
- AcquireL1
- Calibrateradiometric
- Correctatmospheric
- Maskcloud · shadow
- ClassifyEarth…
- Validateground truth
GCRI · Earth observation runEarth observation run, in outline: domain structure with placeholder names and illustrative values, not a record.
The short answer.
Earth observation and remote sensing gather information about the Earth's surface and atmosphere from airborne and spaceborne sensors. Earth observation maps exposure, damage and environmental change across borders and sectors. In the Nexus Consortium, Space and Earth Observation stewards its canonical page, and 5 other platforms apply it, including Water Nexus and Food Nexus.
Land surface in the Hindu Kush Himalaya.
Surface classes an Earth-observation programme reads: ranges, deserts, glaciers, lakes and reefs, shown for the Hindu Kush Himalaya as an example geography for this subject.
What earth observation and remote sensing covers.
- 01
Core methods
image classification; spectral index analysis; synthetic aperture radar processing; change detection; radiometric and atmospheric correction; time-series compositing.
- 02
Data and instruments
optical multispectral satellites; synthetic aperture radar satellites; thermal infrared sensors; airborne lidar; drone imagery.
- 03
Validation
Products are assessed against ground reference data using accuracy matrices and independent samples. Cross-calibration between sensors checks consistency over time.
- 04
Limits
Clouds, revisit gaps and mixed pixels limit what can be observed. Changes in sensors and processing can create artificial trends.
- 05
Use in risk decisions
Earth observation maps exposure, damage and environmental change across borders and sectors. It supports rapid assessment after disasters and long-term monitoring of risk drivers.
Earth observation practice is coordinated through CEOS and open missions.
| Reference | What it sets |
|---|---|
| CEOS Analysis Ready Data | Processing standards so data can be used without specialist correction |
| Copernicus and Landsat | Open-access optical and radar missions |
| International Charter Space and Major Disasters | Rapid satellite data for disaster response |
| STAC specification | Cataloguing of spatiotemporal assets |
Consistent observation across borders.
Satellites observe every country with the same instrument, which makes them uniquely useful for cross-border and data-scarce analysis. The risk is over-reading: a classification of flood extent or crop type has error rates that vary with cloud, terrain and season, and these errors must be carried into any downstream analysis.
- Report accuracy assessments with confusion matrices for classifications.
- Radar sees through cloud but misreads flooded vegetation and urban areas.
- Revisit time limits what fast events can be observed.
- Applications on Space and Earth Observation and Water Nexus.
Who maintains this page.
Space and Earth Observation stewards earth observation and remote sensing: it keeps this description current and reviews how the method is applied across the platforms.
Terms used on this page.
Each term as this page uses it. Where a standard-setting body defines the term, the wording follows that body.
| Term | Definition |
|---|---|
| Synthetic-aperture radar | An active satellite sensor that sends microwave pulses and records their return, imaging the surface day or night and through cloud; open water appears dark. |
| Change detection | Comparing a reference image with an event image of the same place to map what changed, such as newly flooded land. |
| Revisit time | The interval between successive observations of the same place by a satellite or constellation, which limits how quickly a change can be seen. |
| NDVI | The normalised difference vegetation index, a ratio of red and near-infrared reflectance that rises with green vegetation cover and vigour. |
Where this page's references lead.
The bodies and documents this page is read against. Status and editions change; each link goes to the issuing body.
Where this page leads across the Consortium.
- Earth observation for waterGCRIApplied in Water Nexus.
- Earth observation for crop monitoringGCRIApplied in Food Nexus.
- Earth observation for biodiversityGCRIApplied in Biodiversity Nexus.
- Earth observation for hazardsGCRIApplied in Climate and Hazards.
- Earth observation of oceans and coastsGCRIApplied in Oceans and Coasts.
- Earth observation methodsGCRIApplied in Space and Earth Observation.
Questions and answers.
Why does one institution host every method page?
How do I suggest a correction to a method page?
Around GCRI.
Start with an enquiry.
The current service level is R0: information and enquiries. An enquiry receives a reference and names the next step; applications, payments, compute allocations and registrations open only when their team, terms and review capacity exist.