
What makes Paris look like Paris? (2012) - mxschumacher
https://cacm.acm.org/magazines/2015/12/194622-what-makes-paris-look-like-paris/fulltext
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cdoersch
Wow--didn't expect my old paper to re-surface in 2018.

Besides being a neat visualization, one remarkable thing (to me) is that this
is one of the few computer vision tasks where the state-of-the-art is still
the old hand-designed descriptors--specifically HOG. The attempts to re-do
this work with deep learning haven't worked so well. The closest I know is
[https://arxiv.org/abs/1506.06343](https://arxiv.org/abs/1506.06343) , which
I've never even seen applied to cities. The problem is actually that deep nets
have too much invariance: they can classify whether a facade is in Paris or
not, but there's no easy way to separate out different kinds of facades.

If anyone has questions about this work, post below and I'll try to answer.

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keiferski
Anecdotally, after having lived in Paris for ~6 months, one of the most
noticeable aspects of the city is its relative uniformity. Unlike Berlin,
London, or Prague, you can wander for awhile in Paris and essentially see the
same style of architecture and urban landscape repeated. It has something of
an “endless” effect on your time perception.

~~~
eloisant
That's because Paris is stuck in the 19th century with its Haussmannian style.

Usually a city lives and changes to adapt itself to its times, and Paris was
no exception... Until the 19th century.

Now the local government wants to "preserve" it for the joy of tourists, to
the detriments of locals. Housing is scarce causing high prices. Buildings are
old and inconvenients.

Paris is a museum-city. Designed for tourists.

~~~
keiferski
Yeah, I can’t agree, sorry. I’m not sure if you’ve lived in Paris or not, but
these “it’s a tourist city” comments almost always come from people that
haven’t lived there. There are dozens of incredible neighborhoods in Paris
that have little-to-no tourist presence. It’s akin to saying NYC is a tourist
city because Times Square is a mess.

~~~
ovi256
Unfortunately, the rules meant to preserve the Haussmanian parts beloved by
tourists are applied uniformly throughout the city, even in those
neighborhoods without tourists which you mention.

There were deviations from the rules throughout the ages, especially on the
left bank with the newer, taller towers (Place d'Italie, Montparnasse, Berges
de Seine). But these deviations were always one off, pushed through by an
ambitious leader that burned off a lot of political capital.

~~~
realusername
To build taller buildings, you would need much wider streets than what you
have now, unless you want half of the city to be in a permanent shadow. This
would not solve the housing issue. The density of Paris is close to the
maximum possible already.

~~~
tormeh
What's the point of building taller if you just increase the street width so
total livable area per ground area is the same? That's nonsensical. Of course
people will have to live with shadow. It's the only way to increase density
(unless you want people to live in basements).

~~~
realusername
I don't know if you have been to Paris but the streets are VERY small, if you
would build skyscraper, it would not be livable at all. Additionally, you need
extra land for the foundation of the skyscraper (very very difficult to get in
a crowded city like Paris. The point of the skyscraper is that it's cheaper
for the company building it, it only makes sense in that aspect.

~~~
tormeh
Eh, no. Skyscrapers are not cheap. The cheapest thing you can build is
sprawling low-rise.

Some streets in Paris are narrow, others aren't. Streets with two-way road
traffic are wide enough.

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everdev
I've always been amazed at how at the epicenter of a large city or event there
are many normal looking things that contribute subtly or inadvertently to the
overall awe. It's not like everything in Times Square is magical, yet the sum
of them is.

I wonder how many of these more ordinary objects or store fronts you could
remove and still keep the aesthetic wonder of the place. Take out the garbage
cans, the street lights, the cross walks, bring the buildings a little closer
together or father apart. At what point does it's quality simply change?

~~~
harperlee
> This, milord, is my family's axe. We have owned it for almost nine hundred
> years, see. Of course, sometimes it needed a new blade. And sometimes it has
> required a new handle, new designs on the metalwork, a little refreshing of
> the ornamentation... but is this not the nine hundred-year-old axe of my
> family? And because it has changed gently over time, it is still a pretty
> good axe, y'know. Pretty good.

Terry Pratchett, The Fifth Elephant (Discworld, #24; City Watch, #5)

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femto
There is a way to test the validity of their result. Go to figure 6 of the
paper, in which they have a set of "Extracted Visual Elements" for each city.
Cover the captions under each set, then see if you can pick the city. If their
results are valid, shouldn't the essence of the city be in their selected
photos, allowing a person to identify the city by looking at them?

I picked London, but none of the others (which might just reflect my lack of
knowledge of each city). What do others see in figure 6?

~~~
jgtrosh
There's no reason for a human to be as good as the machine, even though it
seems like a very human task. Maybe you can use the results as input to get
better at that task yourself?

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Scarblac
Can this type of software be used the other way around, to turn any picture of
some building into a picture of that building _in Paris_?

That's an effect I've seen with many deep learning things but that I don't
understand.

~~~
cdoersch
The closest I'm aware of is this: [http://papers.nips.cc/paper/6650-toward-
multimodal-image-to-...](http://papers.nips.cc/paper/6650-toward-multimodal-
image-to-image-translation)

However, it requires rectified, segmented training data, unlike the above.

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nailer
I'm not sure Paris _does_ look like Paris. It's quite famous for being a let
down:
[https://en.m.wikipedia.org/wiki/Paris_syndrome](https://en.m.wikipedia.org/wiki/Paris_syndrome)

~~~
HAL9000Ti
"From the estimated six million yearly visitors, [...]around 20 Japanese
tourists a year are affected by the syndrome"

With 0.0003% of people being affected, I'd argue that this so called "symptom"
is hardly a noteworthy phenomenon.

~~~
nailer
The syndrome - with panic attacks etc - is the most severe response. Most
people I know who've been to Paris with high or romantic expectations just get
scammed, spat on, yelled at or robbed and feel a bit disappointed.

~~~
pluma
I've been to Paris a few times and when people tell me they want to go there
for romantic reasons, I just tell them to go to Bruges instead. The Old Town
of Bruges is exactly the way most people seem to imagine Paris: old buildings,
reasonably clean, lots of street cafés and horse-drawn carriages.

Even the Eiffel tower looks better from a distance than close-up (mostly
because it's really just a massive lump of steel). There are nice corners in
Paris but if you haven't actually ever been to Paris before, you'll probably
be disappointed by the overall experience.

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twic
Mansard roofs. It's the mansard roofs. I never noticed them until i moved into
a flat (not in Paris) which is in a mansard roof, and now i'm hyper-aware of
them. Paris has them everywhere, and even has multi-storey ones, which are
very rare in the UK.

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bfuller
I think the smell of Paris is very unique

~~~
lostlogin
The smell of Edinburgh is even more so for me, mostly due to breweries I
think.

~~~
_Wintermute
Depends which way the wind is blowing, if you're lucky it's from the brewery
or distillery, sometimes you get the meat processing plant which isn't so
pleasant.

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dang
Although that publication says 2015, this work goes back to at least 2012:
[https://news.ycombinator.com/item?id=4374542](https://news.ycombinator.com/item?id=4374542).

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buckthundaz
Well, it isn't called the French curve without reason.

