San Francisco in 3D: Cross the Golden Gate on Your iPhone

A bridge across the mouth of the bay, a prison island sitting in the middle of it, and more than forty hills that a flat map quietly irons out. Here is how to explore all of it in full 3D with live Street View, right from your iPhone.

San Francisco occupies the tip of a peninsula in northern California, the Pacific on one side, the bay on the other, and a narrow strait between them that everything drains through. It is small by American standards, roughly seven miles by seven, and famously vertical, built over more than forty named hills rather than around them. Fog arrives through the gap in the afternoon and rewrites the light in half an hour.

The catch is that the city is expensive and its weather is misunderstood. The viewpoints above the bridge are busy year round, and the summer most people book is the foggiest and coolest stretch of the year. Alcatraz tickets sell out weeks ahead. It is easy to arrive with three days, a jacket you did not pack and no view of the bridge.

None of that applies from where you are sitting. You can explore San Francisco today, in full 3D with live Street View, on your phone.

What makes San Francisco special

The Golden Gate Bridge crosses the strait at the mouth of the bay, where the tidal water of a whole river system meets the ocean. It opened in 1937, then the longest suspension span in the world. Its colour was a decision, not an accident: the consulting architect argued for keeping the orange-red primer over the striped schemes the military wanted, because it would read against fog and headland. He was right, and it is why the bridge photographs as it does.

Alcatraz sits out in the bay, close enough that inmates could reportedly hear the city on New Year's Eve. It was a fortification, then a military prison, then a federal penitentiary from the 1930s until 1963, and then, for nineteen months from 1969, the site of a Native American occupation that helped change federal policy. All of it is still on the island, and the cellhouse audio tour uses the voices of men who worked and served time there.

The hills are the third thing, and they are not scenery but the reason the city looks and works the way it does. Telegraph Hill carries Coit Tower and a staircase down its eastern face. Russian Hill holds the crooked switchback block of Lombard Street. Twin Peaks stands near the centre, high enough to watch the grid run to the water in every direction. Some streets have grades over thirty percent, a number you do not feel until you try one.

How to explore San Francisco in 3D

This is where MAPAS comes in. A flat map turns San Francisco into a grid, which is the lie that ruins people's walking plans. In real 3D the grid stands up.

Tilt the map and the hills appear under the streets. Drop into live Street View at the foot of a block and look up it. Circle the bridge towers, cross to the headlands, or trace a route and see how much of it climbs.

For a first run, try this order:

1. Search for San Francisco, California and switch to 3D so the peninsula, the strait and the bay islands take shape.
2. Circle the Golden Gate Bridge at tower height, then swing north to the Marin Headlands for the classic view back.
3. Drop into live Street View at Baker Beach or Fort Point to see the span from below.
4. Fly east to Alcatraz, circle the island, and note how short the crossing to the city looks.
5. Land on the crooked block of Lombard Street, then climb Telegraph Hill to Coit Tower and turn a full circle.
6. Switch on GPS navigation to walk the same route for real when you arrive.

Beyond the Golden Gate

• The Presidio — a former army post turned parkland, with cypress woods running down to the bridge.
• Lands End — a coastal trail on the northwestern corner, past the ruins of the Sutro Baths.
• Golden Gate Park — a long rectangle of gardens, lakes and museums stretching to the ocean.
• The Mission — the city's oldest surviving building, murals in the alleys, the best weather in town.
• Chinatown — the oldest in North America, rebuilt after 1906 and still a working neighbourhood.

Fog, faults and what the ground is made of

The 3D view gives you two things a photograph withholds. The first is the fog, which is less weather than mechanism. Cold upwelled water offshore chills the marine air, the hot interior valleys pull it inland, and the strait is the low gap it funnels through. See the terrain and you understand why the western districts sit under grey all July while the Mission is in sun.

The second is the ground itself. These hills are an accreted jumble of seafloor rock — chert, serpentinite, sandstone — scraped onto the edge of the continent, and the folds read clearly from above. The San Andreas fault runs offshore to the north and comes ashore just south of the city, and the flat, made ground along the waterfront is where shaking has done its worst, in 1906 and again in 1989. Tilt the map and the difference between hill and fill is plain.

Before you go

September and October are the clearest, warmest months. Summer is cool and grey at the coast. Winter brings rain, and some of the sharpest air of the year between fronts. Layers are not optional in any season.

Book Alcatraz well ahead and only through the official ferry operator; those boats are the only legal way onto the island, and they sell out. Expect steep sidewalks, and check the grade before you commit to a route. And treat the neighbourhoods as neighbourhoods: most of what looks like a film set is where people live.

Common questions

Can I walk across the Golden Gate Bridge?

Yes, on the sidewalk, and it is worth doing. Access hours differ by side and season for walkers and cyclists, and it is windier and louder than photographs suggest.

How many days does San Francisco need?

Three covers the bridge, Alcatraz and the central hills. Five lets you add the ocean side, the Mission and a day north into Marin or the wine country.

Is MAPAS free to use?

Yes. It is free on the App Store, needs no sign-up before you start exploring, and works on iPhone and iPad.

No ferry ticket, no parking, no fog on the day you booked. Just San Francisco, in three dimensions, whenever you want to look.

Open MAPAS and cross the Golden Gate in 3D.