Compare imagery of an area
Fix area and dates, open USGS and Copernicus scenes, then use NASA Worldview to place the change in context.
Documents to open in this workflow
This order suggests a starting point; revisit a step if identifiers, dates or versions disagree. Access and reuse terms depend on each service.
USGS EarthExplorer
Find USGS satellite and aerial scenes by area, date and collection.
What to record
Scene ID, collection, sensor, footprint, acquisition, resolution, cloud cover, processing and download date.
Source-specific check
A scene records only its area and acquisition time; compare like processing levels.
Open source portalCopernicus Browser
View and compare satellite imagery and metadata over time.
What to record
Product identifier, sensor, acquisition date, area, resolution, cloud cover and processing applied.
Source-specific check
Publication and acquisition dates differ; inspect clouds over the precise area of interest.
Open source portalNASA Worldview
Browse Earth observation layers and compare dates or phenomena.
What to record
Layer name, stated instrument, selected day, extent and visualisation settings.
Source-specific check
Compare identical settings; a changed palette may create a false impression of change.
Open source portal
Matching condition
Keep scene, collection, extent, acquisition and cloud mask for each product.
If results disagree
Different processing or resolution prevents direct attribution of pixel differences to an event.
Output to produce
Scene and parameter comparison plan.
Separate documentary evidence, demonstrated links between documents and remaining inference. State the owner and review trigger.
Supporting methods
Producer references
Matching table to complete
This is a blank template, not a research result. Record the exact item and observation for each source before making the decision.
| Source | Document or exact URL | Date and version | Observation and passage | Scope and limit | Link established or unestablished |
|---|---|---|---|---|---|
| USGS EarthExplorer | To record | To record | To record | To record | To record |
| Copernicus Browser | To record | To record | To record | To record | To record |
| NASA Worldview | To record | To record | To record | To record | To record |
Frequently asked questions
What link should be checked before matching results?
Keep scene, collection, extent, acquisition and cloud mask for each product.
What if sources appear to contradict each other?
Different processing or resolution prevents direct attribution of pixel differences to an event.
Do the listed portals provide independent confirmation?
Not necessarily. Identify the producer and underlying document. Two interfaces distributing one item can check transcription but do not establish a fact independently twice.