Locate an image or change
Compare map landmarks, satellite acquisitions and observation layers with their dates.
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.
cartes.gouv.fr
Explore IGN maps, aerial photography and public territorial layers.
What to record
Area, coordinates, layer, producer, displayed scale and data date.
Source-specific check
The date you opened the map is not the date of its image or layer.
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
Align extent, acquisition date and resolution; record layers and processing.
If results disagree
If colours change, check palette, clouds and season before inferring physical change.
Output to produce
Dated comparison of products and settings.
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 |
|---|---|---|---|---|---|
| cartes.gouv.fr | 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?
Align extent, acquisition date and resolution; record layers and processing.
What if sources appear to contradict each other?
If colours change, check palette, clouds and season before inferring physical change.
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.