Geolocate the Photo: From EXIF GPS to a Named City
Le défi
Quelqu'un a publié une photo de vacances et un enquêteur veut savoir dans quelle ville elle a été prise. Ouvrez les sources et corrélez-les : la photo contient des métadonnées EXIF cachées, la légende laisse un indice, et une note de recherche d'image inversée repère un point de repère. Combinez-les pour nommer la ville et soumettez-la.
Ce que tu vas apprendre
- Read GPS coordinates out of a photo's EXIF metadata
- Convert a latitude/longitude pair into a country and region
- Use a visible landmark (a named tram line and district) to resolve the exact city
- Corroborate a location with independent context like weather and sunset time
- Understand that stripping a caption does not remove embedded location data
Compétences testées
Prérequis
- Awareness that photos can carry EXIF metadata
- Basic understanding of latitude and longitude
Comment ça marche
Geolocating an image is rarely a single lookup. Sometimes the photo carries GPS coordinates in its EXIF block and the work is trivial; more often you have a country-level fix from one signal and have to narrow it to a city using on-the-ground detail. The discipline is to treat every clue as a constraint and find the one place that satisfies all of them.
Here the EXIF GPS reads 38.7223 N, 9.1393 W, which lands on the Atlantic coast of the Iberian peninsula, and the bio confirms the country as Portugal. That is not yet a city - the coordinates are precise, but the exercise is showing you how to verify rather than trust a single number. The reverse-image note supplies the decisive landmark: a yellow Carris 28 tram, which is the historic Tram 28 line climbing the Alfama district. That line and that district exist only in Lisbon. The weather card corroborates with the same coordinates falling in the capital region and a sunset time that matches the photo's timestamp.
The OSINT board presents each clue as a card. No card names the city outright: GPS gives a point, the bio gives a country, the tram gives a landmark, the weather confirms the region. They converge on exactly one answer - Lisbon.
Erreurs fréquentes
- Answering with the country. The GPS and bio give Portugal; the question asks for the city.
- Ignoring the EXIF entirely. The coordinates are hidden in metadata, not in the visible caption - you must open the EXIF source.
- Missing the landmark. The named tram line and district are what distinguish the city from anywhere else in the country.
- Trusting a single signal. Coordinates can be wrong or spoofed; the landmark and weather corroborate the answer.
Comment s'en protéger
If you do not want a photo to reveal where you are, removing the caption is not enough - the location is usually baked into the file itself. Treat every image you post as carrying hidden coordinates until you have actively stripped them.
- Strip EXIF metadata before posting (most platforms do, but verify - some preserve it).
- Avoid posting recognisable landmarks in real time if location matters.
- Disable camera GPS tagging if you do not need it.
- Remember that timestamps, weather, and shadows can also fix a time and place.