Follow the sun: how shadows tell you which half of Earth you are in
Shadow direction and satellite dish angle split the planet in half in under five seconds — no vehicles, no signs and no road furniture required.
· 5 min read
The short version
- North of the equator the midday sun sits in the southern sky and shadows fall toward the north. South of the equator both are mirrored.
- Geostationary satellites sit above the equator, so satellite dishes tilt south in the Northern Hemisphere and north in the Southern — a hemisphere read that needs no sun in frame.
- The steepness of a dish is a latitude gauge: pointing nearly straight up means close to the equator, angled low toward the horizon means high latitude.
- Long shadows in the middle of a bright, clear day mean high latitude or a winter capture. Shadows collapsing to almost nothing beneath objects mean the tropics.
- A shadow read needs no vehicles, signs or road furniture in frame, which makes it cheaper than the driving-side check — but overcast skies, urban canyons and dusk coverage kill it outright.
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.
Common questions
How do you tell which hemisphere you are in from a photo?
Find a clear shadow and work out which compass direction it falls in. In the Northern Hemisphere the midday sun sits in the southern sky, so shadows point north; in the Southern Hemisphere the midday sun sits to the north and shadows point south. The read is only as good as your bearings, so orient yourself against the compass before you trust it.
Which way do satellite dishes point in the Northern Hemisphere?
South. Geostationary satellites orbit directly above the equator, so a dish anywhere north of it must aim southward to see one, and a dish south of the equator must aim north. The angle is informative too: a dish pointing nearly straight up sits close to the equator, while a dish angled low toward the horizon sits at high latitude.
What does it mean when a Street View image has almost no shadows?
Two very different things. If the light is bright and hard and the shadows are simply short, pooling directly beneath objects, the sun is close to overhead and you are in the tropics. If the light is flat and the shadow edges are soft or missing altogether, the sky is overcast and the technique is unavailable — fall back to road furniture.
Can you work out the season from a Street View image?
Once you have a hemisphere, yes. Bare deciduous trees, snow, low sun angles and long midday shadows all indicate a cold-season capture, and the calendar months that means are opposite either side of the equator. That narrows which coverage campaign produced the image, which occasionally narrows the country.