Tessera

@fil.rezo.net

maps | data | code | journalism #D3 & #Observable 👁️‍🗨️ https://observablehq.com/@fil 🌍 https://visionscarto.net/

Unprecedented drying of 43% of small French streams, as reported by the French Biodiversity Agency (OFB), indicates a critical ecological tipping point following the 2022 drought. Increased climate-driven drought frequency is causing permanent biodiversity loss and ecosystem collapse in waterways.

Dr. Serge Zaka@sergezaka.bsky.social · 9h ago

Cette carte est gravissime. Mais elle n'a pas fait la une de l'actualité. Pour moi, l'été 2026 marque un tournant. Après celui de 2022, il devient difficile de ne plus parler de "rupture écologique" ou de "point de non retour" pour une partie des milieux aquatiques français. 1/18

Jen Mapes @mapesgeog.bsky.social · yesterday

The NACIS schedule is out! Particularly excited about our panel on the fantasy maps of Karen Wynn Fonstad. She was highlighted in the NYT series of overlooked obituaries although they annoyingly refers to her as a "novice cartographer" when she in fact was an expert. www.nytimes.com/2025/01/13/o...

Overlooked No More: Karen Wynn Fonstad, Who Mapped Tolkien’s Middle-earth (Gift Article)

She was a novice cartographer who landed a dream assignment: to create an atlas of the setting of “The Hobbit” and “The Lord of the Rings.”

nytimes.com

Simon Kuestenmacher @simongerman600.bsky.social · 2d ago

Boink! Many more uncontrolled objects re-enter Earth's atmosphere compared to a decade ago. Source: www.reddit.com/r/dataisbeau...

Ansgar Wolsing @ansgarw.bsky.social · 2d ago

The current water level of the Rhine in Cologne is 67 centimeters.

A line chart indicating the water level of the Rhine in Cologne across the year. The current year, 2026, is shown with a think purple line up until August 3rd. The minimum and maximum values for the years 2000 to 2025 are shown as a light grey ribbon.
A darker grey ribbon shows the range within which 80% of the water levels fall.
The chart shows how the water level changes throughout the year. The current year has remarkably low water levels in July and August.

Zeke Hausfather @zekehausfather.com · 3d ago

I'm not sure folks have realized just how crazy the second half of 2026 and 2027 will be for global temperatures – on the back of a record-smashing El Niño event. Here is my latest estimate of where both years will end up compared to global temperatures since 1850.

Matt Khinda @mattkhinda.city · 3w ago

World cup meets world maps: a risograph print of a standard football pattern distorted using different map projections. (yes, I know projections are flat but I like that the shading implies they've been reinflated into the most unusable balls)

A risograph-printed poster showing a standard football pattern distorted by seven map projections. The text is printed in black and the pattern in fluorescent orange.

A detailed view of the risograph printing textures scanned at high resolution.

Abel Vázquez Montoro @abelvm.bsky.social · 3w ago

Worn dirt trails cutting across the lawn while the path bends the long way? Desire paths — now you can simulate them before they exist. Free, open-source pedestrian flow simulator: abelvm.github.io/desire-paths #UrbanPlanning #Walkability

Desire Paths — read where people choose to walk

Drop start and end points on real streets and parks, then see where pedestrians naturally walk — and why the plan fights their instincts.

abelvm.github.io

Observable @observablehq.com · 3w ago

Here @fil.rezo.net reproduces @climatecasino.net’s chart, using warped gridlines to represent both the absolute temperature and the deviation from the historical mean for each day of the year. new.observablehq.com/@fil/godzill...

A line chart with an x-axis showing days of the year, from start of January to end of December; a left y-axis showing temperature, from 22 to 31 ºC; and a right axis showing deviation, from -3σ to 4σ. An orange line shows the mean, starting the year around 26.3 ºC and peaking in May around 27.8 ºC. Faint blue lines show a huge amount of historical data. A bold red line representing 2026 begins the year below the mean, just below 26 ºC, and continues to present day far above the mean, 29.4 ºC. Gray gridlines get “pinched” in the middle, representing narrower summer deviations, highlighting that the current temperature is almost 3.5σ above the mean.

Prof. Eliot Jacobson@climatecasino.net · 4w ago

Breaking News! Code: y-axis alert. Nino 3.4 SST is now up to 3.63 SD above the 1991-2020 baseline, about 1-in-7000 in the absence of anthropogenic warming. There's not enough room in a single post to express just how crazy this is. Please read: climatecasino.substack.com/p/some-monst...

Observable @observablehq.com · last mo.

Here Monica Rizzolli describes her artwork “Forma e Fórmula”. Inspired by Johan Gielis’s “superformula” — a generalization of the superellipse — she developed a “curatorial interface” for curves and a “herbarium of generative flowers” new.observablehq.com/@dac4b2f6fec...

Observable @observablehq.com · last mo.

Here nxrix (@nxrix.bsky.social, I suppose?) extends Plot with a custom mark rendering GLSL shaders to demonstrate domain coloring for complex-valued functions, with interactive pan and zoom new.observablehq.com/@nxrix/domai...

@robertfathauer.bsky.social · last mo.

Over 5,500 mathematical artworks can now be browsed in an attractive new gallery-wall layout on the Bridges website, thanks to the efforts of Nathan Selikoff: gallery.bridgesmathart.org/gallery?seed...

Jo Wood @jwolondon.bsky.social · last mo.

London Data Week #LDW starts today with an interesting and packed programme of free events (but book in advance): londondataweek.org/ldw26-events/ I will be giving a talk on Friday about revealing voting biases with 📊 following the recent local elections. londondataweek.org/ldw26-events...

BallotMap for London showing name-ordering bias in ranked votes

A grid of 32 squares arranged in an approximate diamond shape representing the 32 boroughs of London.

Each square is a London borough. Within each, the candidates for the main parties are shown as coloured lines (Greens: green, Labour: red, LibDems: orange, Conservatives: blue, Reform: cyan, Aspire: pink). They are ordered in rows where the top row is the alphabetically first candidate within their party and ward, the second row alphabetically second, and the bottom row alphabetically last. Darkest lines are those where the candidate received most votes within their party; medium lines where they received the middle number of votes within their party and lightest lines where they received the fewest.

Only those in ballots where they were one of three party candidates shown.

This allows us to see where people have split their vote between parties, choosing just one or two from the slate of three in a given party.

A darker lines in the top row compared to the bottom row of each square indicates voting perference for candidates with names closer to start of alphabet.

We see darker lines in the top row for every borough in London. Some boroughs with particularly strong name bias (strong contrast between top and bottom rows) include Enfield (Enf), Havering (Hvg), Bromley (Brm) and Merton (Mrt). Slightly weaker effects can be seen in Richmond (Rch) and Tower Hamlets (Tow) where party preference exerts a strong influence.

Voting data: Democracy Club, 21st May, 2026.

Observable @observablehq.com · last mo.

This is a Bluesky post about a notebook about embedding Bluesky posts that embeds this Bluesky post. new.observablehq.com/@tophtucker/...

Bluesky

An Observable notebook by Toph Tucker

new.observablehq.com

Mike Bostock @ocks.org · 3mo ago

In this week’s Observable Podcast, co-CEO Julio and I discuss our mission to make computation easier for humans to use and understand. We need a better medium! youtu.be/0uBOL9NP8Iw?...

What even is Observable? | Observable Podcast

YouTube video by Observable

youtu.be

Saloni @scientificdiscovery.dev · 5mo ago

The number of organs available for donation has risen massively in the past five years. It seems to be the result of technological advances in preserving organs after circulatory death. jamanetwork.com/journals/jam...

Chart of trends in recovered organs from circulatory deaths

Françoise Bahoken @fbahoken.bsky.social · 5mo ago

Et les nerfs de nos chairs comme des cartes marines, dans Panthere Première pantherepremiere.org/texte/et-les...

Entretien avec Sarah Maldoror, présidente de la Troupe Les Griots à propos de la pièce Les Nègres de Genet. Propos recueillis en 1958 par Marguerite Duras. Planche de bande dessinée au graphisme stylisée en niveaux de gris 1/2

Observable @observablehq.com · 5mo ago

When D3 was released in February 2011, it transformed how we build data visualizations for the web and ushered in a new age of unbridled creativity in information design, data journalism, and beyond. Today, it remains the backbone of modern, interactive data viz. Happy 15th birthday, D3 🎂 d3js.org

Andrew Heiss @andrew.heiss.phd · 6mo ago

I just whipped up this little #QuartoPub site last week that demonstrates how I teach p-values/hyp-testing through simulation both with live OJS and with #rstats, and I think it's super neat! It has examples for diff-in-means, diff-in-props, and regression slopes nullworlds.andrewheiss.com #statsky

Simulated null distribution for data with a sample size of 100, difference in group means of 5, and a p-value of 0.142

Simulated null distribution of a slope of 0.8 and p-value of 0.002

Finally, we have to decide if the p-value meets an evidentiary standard or threshold that would provide us with enough evidence that we aren’t in the null world (or, in more statsy terms, enough evidence to reject the null hypothesis).

There are lots of possible thresholds. By convention, most people use a threshold (often shortened to α) of 0.05, or 5%. But that’s not required! You could have a lower standard with an α of 0.1 (10%), or a higher standard with an α of 0.01 (1%).

Statistically significant
The p-value is < 0.001 and our threshold for α is 0.05

In a world where there is no relationship between x and y, the probability of seeing a slope of at least 0.901 is < 0.1%

Since < 0.001 is less than 0.05, we have enough evidence to say that the slope is statistically significant.

Evidentiary standards

When thinking about p-values and thresholds, I like to imagine myself as a judge or a member of a jury. Many legal systems around the world have formal evidentiary thresholds or standards of proof. If prosecutors provide evidence that meets a threshold (i.e. goes beyond a reasonable doubt, or shows evidence on a balance of probabilities), the judge or jury can rule guilty. If there’s not enough evidence to clear the standard or threshold, the judge or jury has to rule not guilty.

With p-values:

If the probability of seeing an effect or difference (or δ) in a null world is less than 5% (or whatever the threshold is), we rule it statistically significant and say that the difference does not fit in that world. We’re pretty confident that it’s not zero.
If the p-value is larger than the threshold, we do not have enough evidence to claim that δ doesn’t come from a world of where there’s no difference. We don’t know if it’s not zero.
Importantly, if the difference is not significant, that does not mean that there is no difference. It just means that we can’t detect one if there is. If a prosecutor doesn’t provide sufficient evidence to clear a standard or threshold, it does not mean that the defendant didn’t do whatever they’re charged with†—it means that the judge or jury can’t detect guilt.

@fil.rezo.net · 10mo ago

…published a new version of d3-tricontour observablehq.com/@fil/multipo...

Multipolygon tricontour

Since v1.1.0 d3-tricontour can compute multipolygonal contours.

observablehq.com

Yusuf @yusufimaadkhan.com · 11mo ago

Reminded me of this (if you think of structural breaks as shifting between equilibria on an S-curve). observablehq.com/@fil/fitting... web.archive.org/web/20220523... Also shows why historical/domain-specific intuition is so important. HT @fil.rezo.net and Constance Crozier

Fitting a sigmoid

This notebook tries and reproduces this eye-opening experiment by Constance Crozier. Conclusion: even with a very small noise, predicting a sigmoid model by fitting the past values is pure folly; note...

observablehq.com

Yakov Feygin@buddyyakov.bsky.social · 11mo ago

Playing with a shower idea of a way to explain the implications. If we accept the market as big computer metaphor, the computer is quite good at running say a regression model and defining the best fit. What it is not great at is identifying a structural break in a series with very little data.

James King @jamesking.io · 11mo ago

Big fan of @observablehq.com and since their preview release of Observable Notebooks 2.0 my team at Fora Health have integrated Notebook Kit into our app. Works really well so far. Quick demo ⬇️ screen.studio/share/TqvyfFbU

Observable Notebooks 2.0 in Fora Health — Screen Studio

Observable Notebooks 2.0 in Fora Health — Created and shared with Screen Studio

screen.studio

Mike Bostock @ocks.org · 11mo ago

Observable Notebook Kit and Desktop 1.1 are out. Headline feature: database connectors! 🎉 You can now query DuckDB, SQLite, Postgres, and Snowflake directly from notebooks. And it’s self-hosted. And it saves results automatically for performance and stable analysis. observablehq.com/notebook-kit...

Observable Notebooks Database connectors | Observable

observablehq.com

Andrew McNutt @mcnuttandrew.bsky.social · last yr.

charts you hate to see

a choropleth map of the western us highlighting the federal lands that are proposed to be sold, colored by blm and USFS

Martin H. Trauth @martinhtrauth.bsky.social · last yr.

Very interesting open access article about the "Long-term impact and biological recovery in a deep-sea mining track" by D.O.B. Jones and colleagues. Their photos of the ocean floor after mining, before and after, are simply shocking. #geoscience www.nature.com/articles/s41...

Typical photograph of undisturbed seabed at the control site with polymetallic nodules, from Jones et al., Nature, 642,112-118, 2025.

Area of track with complete removal of nodules by deep-sea mining in the centre and deeper propulsion tracks either side, from Jones et al., Nature, 642,112-118, 2025.

Jason Reid @jasonreiduk.bsky.social · last yr.

If you want to go, there’s just one more day of viewing (Monday 16th). Bring tissues.

Taylor Shelton @jtsphd.bsky.social · last yr.

Atlanta is the most surveilled city in the United States. But because the Atlanta Police Department claims that releasing the locations of these 60,000+ cameras will lead to terrorism, we’ve not been able to map their locations... Until now. Read more 👇👇

City of Cameras

Atlanta is the most surveilled city in the United States. With 124.14 surveillance cameras per 1,000 people, we not only lead the country, we have more than twice as many cameras per capita as 2nd …

mappingatlanta.org

André Loez & podcast Paroles d’histoire @andreloez.bsky.social · last yr.

Fut un temps où les questions géopolitiques avaient une place de premier plan dans l'espace public en France, y compris avec de fantastiques efforts carto & dataviz Les modifications de #frontières dans les Balkans à la Une du journal Excelsior, 21/2/1921

https://gallica.bnf.fr/ark:/12148/bpt6k4603552m/f1.image

Corin Faife @corin.bsky.social · last yr.

As the United States vetoes another Israel-Palestine ceasefire resolution at the UN Security Council, here's a graphic I made for @afp.com showing every veto on a similar resolution since 1970.

@fil.rezo.net · last yr.

bump bump

Interactive Journalism@interactives.bsky.social · last yr.

New on The New York Times : “Do You See Craters or Bumps on the Moon’s Surface?”

Shannon Mattern @shannonmattern.bsky.social · last yr.

"The 1930’s International Atlas of Clouds + of States of the Sky... provides a detailed textual description of different kinds of clouds, their shapes, the occurrences of the clouds, their behaviour, and a description of the disturbances the clouds indicate." socks-studio.com/2024/03/24/o...

A page of the atlas featuring two photos of clouds and two diagrams describing their types and characteristics

A page of the atlas featuring a photo of cirrus clouds and a diagram of its filaments