Half the planet is the wrong half. Here is how to delete it.
This costs you nothing. No vehicle has to be in frame, no sign has to be readable, no bollard has to exist. You need one lit object standing on the ground, or a dish on a roof.
The rule
The apparent path of the sun differs either side of the equator, and it differs in a way you can read off the ground.
North of the equator, the sun tracks across the southern sky. At midday it sits to your south, and shadows fall toward the north.
South of the equator it is mirrored. The midday sun sits to your north, and shadows fall toward the south.
Get your bearings first
The rule is useless unless you know which way you are facing. Street View gives you a compass. Use it: orient yourself, then read the shadow direction against true north rather than against the road.
If you do not trust the compass, the carriageway will do. Shadows falling consistently across the road in one direction, combined with your direction of travel, still gives you a usable read.
Satellite dishes: the cheat
This is the one most players miss.
Geostationary satellites sit above the equator. Dishes have to point at them. So in the Northern Hemisphere dishes tilt south, and in the Southern Hemisphere they tilt north — regardless of cloud, time of day, or whether there is a single shadow in the frame.
Better still, the steepness of the tilt varies with latitude. A dish pointing nearly straight up suggests you are close to the equator. A dish angled low toward the horizon suggests high latitude.
Dishes are on rooftops across most of the inhabited world, they never move, and nobody thinks to check them.
Shadow length is a latitude signal
Direction gives you the hemisphere. Length gives you a band within it.
- Long shadows in the middle of a bright, clear day
- High latitude, a winter capture, or both. Stack it against the vegetation to decide which.
- Short, hard shadows
- Low latitude, or summer. The light is coming from high overhead.
- Shadows pooling directly beneath objects
- The tropics. Near the equator the direction rule breaks down entirely, but the collapse itself tells you where you are.
- Soft-edged or absent shadows
- Cloud, not geometry. This is a failed read, not a short one.
Cross-check with the season
Once you have a hemisphere, run the season against it. Bare deciduous trees in the Northern Hemisphere mean a winter capture. Bare trees plus a Southern Hemisphere read means the opposite half of the calendar. That constrains which coverage campaign you are looking at, which occasionally constrains the country.
| What you see | Northern Hemisphere | Southern Hemisphere |
|---|---|---|
| Midday sun | In the southern sky | In the northern sky |
| Midday shadows | Fall toward the north | Fall toward the south |
| Satellite dishes | Tilt south | Tilt north |
| Bare trees and low sun | Captured in the northern cold months | Captured in the opposite half of the calendar |
The failure cases
Four conditions take this technique off the table:
- Overcast skies, which remove directional shadows entirely.
- Dense urban canyons, where the shadow you can see was cast by a building and tells you about the street grid, not the sun.
- Heavy tree cover, which shreds a single shadow into dappled noise.
- Night, dawn and dusk coverage, where the sun is low enough that shadow direction is dominated by time of day rather than hemisphere.
When it works, though, this is the cheapest halving of the world available.
Cheaper even than driving side, because it needs no vehicles in frame at all.