Londology A curious atlas of London

Methods

Everything here is built from public data, offline, from files kept in the repository. The site fetches nothing while it builds. That is not a technical detail: it means a chart on this page can be reproduced later from the same numbers, rather than from whatever the source published this morning.

Confidence marks

Claims that carry weight are labelled with how certain they are. Three levels, no more — a page dense with badges is as uninformative as a page with none.

Fact
Documented in a cited source. I can show you exactly where. A number is a fact only when the sentence says what it measures: "the highest recorded monthly mean of any line in this series" is a fact; "the hottest line" is a vibe.
Interpretation
My reading of solid data. Someone competent could read the same numbers differently, and the piece should make it possible to see how.
Hypothesis
An educated guess. It is never published bare: it arrives with the evidence that would confirm or kill it, which is usually the seed of the next piece.

Where the numbers come from

Each piece has a manifest listing every dataset behind it: the publisher, the licence, the exact attribution the publisher requires, and the date it was retrieved. The page prints that manifest rather than a summary of it, in the Behind-the-data block at the end of every analysis. If a licence is unresolved, the piece does not publish — the build refuses it.

Every figure carries the table behind it, in a collapsible block. Charts are drawn at build time and shipped as static images: an article with no interactive map sends no JavaScript at all.

What "data as of" means

It is the last date the data covers, not the day it was downloaded. A dataset that stopped in December 2024 says so, and pieces built on it say so too. Where a series ends early, that is part of the finding rather than a footnote.

AI assistance, disclosed

Drafts are AI-assisted and AI-copyedited. The judgement — which question to ask, what the data can and cannot support, what to leave out — is mine, and the confidence marks are what make that judgement visible. No sentence here makes a claim its sources do not support; when one would, it gets a badge or it gets cut.

Corrections

Slugs never change after publication. Corrections happen in place, with a dated line saying what changed. If a piece is wrong, the record of it being wrong stays on the page.

This page is a skeleton. It is finished alongside the weird-laws piece, which is where the confidence marks first do real work for a reader.