GCRI · Space and Earth Observation
Methods and uncertainty
The methods Space and Earth Observation relies on: their equations and assumptions, the data they need, how they are validated and the limits of what they can show.
Methods and uncertainty in five parts.
The methods in use.
- 01Earth observation and remote sensingChoosing sensors for a question · Change detection over time · Validating derived productsApplied here
- 02Space systems and satellite servicesMission continuity analysis · Space segment resilience · Debris compliance assessmentApplied here
- 03Geospatial information systemsIntegrating EO with administrative data · Catalogues and interoperabilityApplied here
- 04Spatial statistics and geostatisticsArea estimation with error-adjusted counts · Stratified sampling designApplied here
- 05High-performance, cloud and edge computingAnalysis next to the archive · Reproducible processing chains · National data cubesApplied here
- 06Communications and network technologyData distribution to users · Spectrum protection for EO · Ground station networksApplied here
- 07Physics and quantum scienceRadiative transfer for atmospheric correction · Microwave scattering · Orbit determinationApplied here
Each method, its role in this field and how it is checked.
- Earth observationRole hereEarth observation and remote sensing is the technology this platform stewards for the network.Checks appliedAccuracy with intervals; Sensor consistency; Independent reference
- Space systemsRole hereSpace systems and satellite services is the second technology this platform stewards.Checks appliedStatus verification; Guideline mapping; Scenario coverage
- GeospatialRole hereGeospatial information systems manage location data and combine Earth observation with maps of people, assets and boundaries.Checks appliedBoundary version control; Standards validation; Positional checks
- Spatial statisticsRole hereSpatial statistics give Earth observation its quantitative rigour: sampling designs for accuracy assessment, unbiased area estimation, spatial interpolation and models that combine satellite data with ground observations, each reported with its uncertainty.Checks appliedDesign-based inference; Interval reporting; Spatial cross-validation
- ComputingRole hereHigh-performance and cloud computing let Earth observation scale from single images to petabyte archives.Checks appliedVersion recording; Regeneration test; Cost accounting
- CommunicationsRole hereCommunications technology links satellites to ground and users to services.Checks appliedLatency measurement; Interference flagging; User access testing
- PhysicsRole herePhysics explains how satellite sensors measure the Earth: radiative transfer through the atmosphere, microwave scattering, thermal emission and orbital mechanics.Checks appliedModel intercomparison; Uncertainty propagation; Calibration site checks
How the process runs.
Process explorer · Process
Methods and uncertainty: Source to evidence record
10 steps·4 stages·2 gates
Process
Methods and uncertainty: Source to evidence record
A source is registered and assessed, its record labelled and classified, and a Digital Evidence Passport carries provenance; a correction reaches every dependent record.
01 Intake
- 01Identify the sourceSource · The source stewardDiscovery is not ingestion. Source identification records the source class, steward, institutional role and jurisdiction.
- 03Register the sourceStepRegistration makes a discovered source a governed participant in the evidence lifecycle. It implies no endorsement or certification.
02 Assessment
- 04Jurisdiction and rights classificationGateRights classification identifies licence, consent, confidentiality and reuse limits. The result determines access and routing.
- 05Evidence quality assessmentStepQuality assessment decides whether a record is fit for a defined use. Quality is multidimensional and never a single score.
- 06Evidence labelStepEvery finding carries one of nine evidence labels. Missing data is shown as missing, never as zero.
03 Record
- 07Evidence classificationRecordClassification gives records lifecycle states, such as source-verified, public-safe or restricted. States can coexist and set evidence use.
- 08Source release and identifierRecord · NXS-GRX (canonical data, provenance and risk)A source release records rights, temporal coverage and source lineage. A UNI is allocated through a catalogue and never typed by hand.
- 09Digital Evidence PassportRecordThe passport records provenance, quality, rights, jurisdiction, permitted use and history, so evidence keeps its context when it travels.
04 Use and correction
- 02Correction reaches dependent recordsStep · NXS-GRX (canonical data, provenance and risk)A source correction propagates to dependent cuts and products without rewriting old results.
- 10Public-safe reviewGatePublic-safe review decides whether a record can be shared publicly. It is a distinct stage and is not validation.
Data protocols: evidence lifecycle · Data protocols: core data objects and evidence records · The Global Risks Index (NXS-GRX)Designed programme process, not a record of operation. No cycle has run and every programme is at service level R0. A gate is a programme decision, never a public-authority approval, certification or deployment authorisation. The data-protocol pages describe a design, not a running system.
Where uncertainty in Earth observation analysis comes from, and how it is shown.
| Source | Why it matters here | How it is reported |
|---|---|---|
| Classification accuracy | Varies with region, season and class | Accuracy assessments per product |
| Revisit and cloud | Limit what fast events are seen | Observation dates stated |
| Geolocation | Errors matter for small features | Accuracy stated |
| Sensor continuity | Missions end; records break | Record continuity noted |
Every derived map states sensor, date and accuracy.
How uncertainty is reported.
- 01
State assumptions
Each analysis lists its assumptions and the data it depends on.
- 02
Quantify where possible
Ranges and confidence are reported alongside central estimates.
- 03
Validate and compare
Models are checked against observations and, where possible, against other models.
- 04
Publish limits
What an analysis cannot show is stated beside what it can.
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.
Questions and answers.
Are the methods open?
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