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diffraction-limited t1_jdqhhfy wrote

Would have loved to see the residuals of that exponential fit. They look a bit off even by eye? Not sure if this is the proper model since with the areal distance the area accessible to build houses raises with a square, so the simplest model I'd try is to use something with an inverse square law no?

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PredictorX1 t1_jdqjeq7 wrote

That's interesting. Can you supply some measure of performance (mean squared error, mean absolute error, ...) for those curve fits?

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CeruleanBoolean141 t1_jdqkt4k wrote

Why is a 4-7 room apartment cheaper than a 1 room? Does 4-7 room mean it’s like communal living like a student dorm?

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sudu1988 OP t1_jdql91k wrote

Replying to CeruleanBoolean141 (#2,368,820)

4-7 rooms means that these are offered apartments, which have between 4 and 7 rooms. It's up to you if you can afford and live alone or share it with other people. I do believe that 1-bed apartments are most expensive per square meter because 1) there is the highest demand (to use them within the week and go back to family on weekends), and 2) because you have fixed costs (council tax, ...) included, which are scaled by less square size. In France everything except gas and electricity is included already into the rent.

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sudu1988 OP t1_jdqlt0v wrote

Replying to diffraction-limited (#2,368,940)

Well, the results looked much more off. But you are right, I should add some information on the mean squared error. In my article I didn't wanted to shock people with it, because it's kind of more informative post.

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diffraction-limited t1_jdqm5ej wrote

Replying to sudu1988 (#2,368,991)

Yeah i get that, but for me that would be the interesting part. Making a model is just one part, choosing if the model is correct is a whole different story :) And i still think that adjusting an inverse square model might be worth trying, no? The price is based on available space, and this correlates with a square and not an exponential function. Not sure why I feel so strongly about that, sorry:)

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Furkhail t1_jdqnh3c wrote

Replying to CeruleanBoolean141 (#2,368,820)

It's not the price of the apartment but the square meter price. A double berdroom apartment is more expensive than a single bedroom but the square meter won't be. For example. Single bedroom 50m2 500€. Goes at 10€/m2. A four bedroom aparment 150m2 1200€. That's 8€/m2. More expensive in total cheaper in €/m2

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fallen-soul_ t1_jdqr1q2 wrote

Replying to CeruleanBoolean141 (#2,368,820)

1 room apartments are popular among students here in Paris, because the overall rental price is still much cheaper than a 2-3 room apartment. Since demand is high for cheaper rents, it explains in part why the price per unit (m²) is higher for smaller apartments. I'd also add that i think there is relatively less student housing (exclusively for students) in central Paris than other European cities (my own impression, I haven't checked the numbers.)

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DazedWithCoffee t1_jdqs66g wrote

Very cool, if you can expand this to other cities that would be very interesting

Also, if you could plot this against the mass of garbage outside each, that would be great /s

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legagneur t1_jdqt7ox wrote

I had a friend who owned an apartment right across the street from Notre Dame (literally right across the street, maybe 20 meters away).

It was the most gorgeous apartment I’ve seen in my entire life. We used to sit on his balcony for meals and just watch everyone walk by, the cathedral just an arm’s reach away.

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legagneur t1_jdqtfi7 wrote

Replying to DaleGribble312 (#2,369,098)

Seven rooms or seven bedrooms? The graphic doesn’t specify, so I’d assume seven rooms.

I lived with a French family who owned a building. The floor of their residence was about five rooms or so, but included living areas (salon, formal dining area, etc) as well.

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hmiemad t1_jdqtj4j wrote

In the article, Fig 12, on the left, we see a clearer relation of total rent vs size. There is a clear intercept (337.55€, say C). I think you should rerun the regression with taking this into account : (price-C)/size vs distance. And finally, when you find the relation (exp, linear, quad, whatever, say F ), you run a regression on price = C + F(distance) * size.

Also, there are robust ways to run regression, better than just remove the outliers once and rerun. Huber is your friend, as are statsmodel/sklearn (both built on top of scipy).

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TheHappyEater t1_jdqw2nz wrote

What's with the weird strata at 50,and 60km? Are these self-reported distances?

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mikehawk1988 t1_jdqxusv wrote

Next time give us an adjusted R² too, makes it more interpretable

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Posnania t1_jdqyo3y wrote

BTW, the major central crossway for Ile-de-France transit network is Chatelet Les Halles, about 1 km from Notre Damme cathedral, and 1 km from Louvre, 400 meters from Pompidou Centre, and so on.

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r_linux_mod_isahoe t1_jdr1bg2 wrote

We really need to start teaching people how to do a non-linear regression. Why would you ever do a parametric fit on over 100 data points in a 1D input space?

lowless is your friend

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tyen0 t1_jdr1v8a wrote

Replying to sudu1988 (#2,368,230)

> [OC] posts must state the data source(s) and tool(s) used in the first top-level comment on their submission.

not just a link to your blog.

(and I can't find the data source on your blog, either.)

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DataMan62 t1_jdr4opf wrote

To compare this to my American expectations, I found that

  1. A sq m is about 11 sq ft (1600 sq in / 144 sq in).
  2. The € is worth about $1.08 right now. It’s been as low as 85¢ in 2001 and as high as $1.59 in 2008.

So a hypothetical 1100 sq ft apartment (say 30’ x 37’) 10 km (6.2 mi) from Notre Dame would run anywhere from €1500 to €5000 per month. ($1620 to $5400 / month)

I’m guessing apartments in Paris are mostly small to tiny. What is a typical size for studio, 1-, 2-, and 3-bedroom apartments? What’s the minimum size?

Does number of rooms count bathrooms?
Is a kitchen usually counted as a room?
Do all apartments in Paris have bathrooms and kitchens? Even 1-room apartments?

Thanks for the data and the plot.

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BWWFC t1_jdr6m6s wrote

interesting value cluster for 4-6 rooms at 23km

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96385 t1_jdr6v8y wrote

Replying to TheHappyEater (#2,370,428)

I thought these might be self-reported distances too, but then I remembered apartments aren't built with uniform density around a city. It might just be due to unequal concentrations of population in the suburbs.

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fallen-soul_ t1_jdradik wrote

Replying to DataMan62 (#2,371,524)

Hey, I'm from Paris.

>I’m guessing apartments in Paris are mostly small to tiny.

objectively speaking (and relative to other cities in the world), I think you can say that. I'll speak for central Paris, since that's where I and most of my friends so far have lived.

Studios go from 8m² to 20m², the majority being between 8-15m², mostly inhabited by students or young professionals. It might sound crazy, but within that category a big number of studios are in the 8-10m² and are still in high demand: usually they have a bed, a tiny sink, hot plate and shower, and the toilet is outside and shared; we still call them "maiden rooms", as they used to have that purpose back then, and they're usually on the last floor of a typical parisian ("Haussmanien") building.

I'd say 1-bedroom apartments usually range from 20m² to 30m² - from that surface upwards, the vast majority have their own bathroom - , and 2-bedroom apartments (maybe the most common type, I'm not sure) anywhere from 30m² to 70-80m². I've lived with my parents in a 45m² 2-bedroom apartment my entire life so far and I'm moving out soon (guess why... lol); the kitchen and bathroom are not counted as rooms, only bedrooms and living rooms are. Currently, 45m² 2-bdrm flats can cost from €400k to €600k in central Paris, maybe even €700k in the most expensive areas, it's completely fucking nuts. 3 adults can barely live together in such a small surface.

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tyen0 t1_jdrox29 wrote

Replying to sudu1988 (#2,373,110)

It's not asking you to sticky it, just that it be your first top level comment, which you did.

I was just complaining because you didn't provide any links to the data sources. (I wanted to verify the 1 room vs 1 bedroom discrepancy)

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Sequitur1 t1_jdrqxm1 wrote

Replying to ntnl (#2,371,944)

Next to a Catholic church that covers up child molestation, thus the headline. Says nothing about city center and sheep as defined in the bible and quoted by Mr. Rogers on his death bed: "All the nations will be gathered before Him, and He will separate them one from another, as a shepherd divides his sheep from the goats. And He will set the sheep on His right hand, but the goats on the left” (Matthew 25:31-33).

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Fondren_Richmond t1_jdrsljq wrote

studio near old Notre Dame

penthouse ten leagues far rent's still the same

studio no heat or A/C

penthouse has in unit laundry

studio no parking off-street or on-

penthouse reserved lot space for each one

studio don't take packages that

penthouse doorman signs for

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redasphilosophy t1_jdrw3jb wrote

Replying to TheHappyEater (#2,370,428)

Explanation attempt : while the 20 first kilometers around Notre-Dame are uniformely urbanised, areas beyond are more rural with an agglomeration or two here and here. For instance the 50 km stratum could correspond to Mantes-la-Jolie, the 70km one could be Chartres or Compiègne.

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springlord t1_jdscfb1 wrote

TIL: Ile-de-France can be as far as almost 100 km from the center of Paris.

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doktorjake t1_jdse7c8 wrote

This is beautiful data. Too many moving bar charts lately. Scatter plots are the most informative and most interesting.

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diffraction-limited t1_jdsez93 wrote

Replying to MarchelloO (#2,374,394)

It's a visual check if there is still hidden data in your fit. If the residuals seem to be randomly distributed, it's a good first rough check that your model covers all the available data. Usually you find the residuals moving all in one, and then all in the other direction, looks a bit like a wave-y very noisy motion along the x axis.

There are more robust ways to check like Anderson darling if I'm not wrong, but the residuals are easily plotted and a good quick and dirty first check

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RoastedRhino t1_jdsmhwl wrote

Distance in what norm?

I would be curious to see what is the effect of a "travel time" distance, it could explain some high prices far away (but very well connected to the city) and make the curve fitting a bit easier.

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magicbobcat t1_jdspblw wrote

I wonder - does this track for selling prices as well?

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vkfu t1_jdt1gy8 wrote

Do a log transformation on your dependent variable

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hmiemad t1_jdtapst wrote

Replying to sudu1988 (#2,370,121)

Once you get it, map the standardized error with colorscale. And don't do the cheap average per departement or municipality. I know for a fact that in 18th and 17th arrondissements of Paris, you can get very different rates. So for each appartment, one point on the map with the error as color. Rich neighbourhoods should pop up.

​

edit : for mapping purposes, take a look at geopandas. very close to pandas. easy to use : gdf.plot()

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Redcarborundum t1_jdthlhp wrote

There are dense vertical clusters around 25km and 48km from Notre Dame. I wonder what popular areas are at that distance from the cathedral.

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DataMan62 t1_jdtodqn wrote

Replying to fallen-soul_ (#2,372,230)

Wow! More severe conditions than I expected, but are the prices you mentioned, and on the chart, prices to buy? We call that a condominium. I was under the impression the chart was monthly rent. We refer to rental units as apartments.

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morhe t1_jdu06dh wrote

Replying to MarchelloO (#2,374,419)

You can draw any line you want. From something crazy and nonsensical to something that looks nice and smooth like the ones here. The fact that the lines “look” nice means nothing if they are not a realistic representation of the distribution of the data. So, the lines might be pretty but not significant but we can’t tell without a measure

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ljog42 t1_jdubw2u wrote

Paris has a diameter of 6km/8km, more than 20km is barely the suburbs anymore

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fallen-soul_ t1_jduj4qs wrote

Replying to DataMan62 (#2,383,193)

yes the chart is monthly rent, and the prices I gave are prices to buy indeed. We don't rent our apartment, so I'm more aware of sale prices for that category.

Btw when I say central Paris, I'm talking about the area within the perimeter of the ring road we call périphérique, so less than a 5-6km (3-3.5mi) distance from Notre Dame

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rackelhuhn t1_jdut32m wrote

Replying to r_linux_mod_isahoe (#2,371,098)

I don't know why you're getting downvotes, maybe the statement is expressed a a bit too absolutely, but with large datasets and few dimensions there are almost no downsides to flexible regression approaches (LOESS, splines etc.) There is no reason to fit an exponential regression with this much data.

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sudu1988 OP t1_jdzqcp4 wrote

After removing my shaddow ban and restoring the post, it's online again 😊🥰

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