Geolocation Challenges

The discipline

Geolocation means determining where a photo or video was taken from visual clues alone — no metadata, no GPS. CTF challenges provide an image and ask for GPS coordinates or a place name.

Layer your clues

Work from the macro to the micro:

1. Country — road markings, driving side, script/alphabet, flora, sky colour.
2. Region — architecture, terrain, infrastructure style.
3. City — recognisable landmarks, street signage, chain stores.
4. Street — house numbers, utility poles, company logos.

Environmental tells

Clue	Narrows to
Red octagonal STOP sign	North America
White on blue highway signs	Europe
Yellow lane markings	USA, Canada
Left-hand traffic	UK, Japan, Australia, India
Baobab trees	Sub-Saharan Africa
Birch trees	Northern Russia / Scandinavia

Power lines and poles

Wooden poles = North America, Japan, rural developing world. Concrete poles = Eastern Europe. Underground cables (no poles) = Western Europe, Scandinavia.

Reverse image search workflow

1. Upload to Google Lens → “Search image” → look for identical locations.
2. Try Yandex Images — much stronger for non-Western locales.
3. Crop to the most distinctive feature (a building, a sign) and search that crop separately.

Confirming with Street View

Once you have a candidate location:

1. Open Google Maps.
2. Drop into Street View at the candidate.
3. Rotate to match the camera angle in the challenge image.
4. Match at least 3 independent features before committing.

Shadow analysis

The sun’s position reveals the time of day and — combined with the photo date — the latitude. Tools like SunCalc let you overlay shadow direction on a map.