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50fbac7

Here. That's the Transport Act B.E. 2497 (1954): §12 lets the committee set routes and how many operators get licensed, via Gazette notice. So the route announcements after it should show how routes changed. Want me to dig into those?
On text: old PDFs are image-only scans, no text layer. The 2021 reform one has real text. Dataset OCR starts 2002. So the text era is ~2002+, roughly 3k notices. Notes are in NOTES.md in the repo.
Can we make like a database of a changelog of each bus route? So given a route, we can see when it was established, when was it revised, etc. with deep links into the PDF.
Known wart, see the Bangkok route 1 shot: air-con ปอ. 1 and ordinary 1 share a page, and the 2021 reform's numbers (4-70E, 5-1) are in the same list. Next could be: split those, then use text layers for the body-only notices. Which first?
Wart = known flaw. Bangkok "route 1" page mixes 3 different things: air-con ปอ.1 คลองจั่น-ปากคลองตลาด (1978, 1982), ordinary สาย 1 ถนนตก-ท่าเตียน (2007), and the 2021 reform notice.
Diagram. A: my "route 1" page merges 3 unrelated things just because the titles say "สายที่ 1". B: your reform PDF is one notice for 258 routes (G/B/R/Y codes renumbered to 1-xx…4-xx), but its title names only route 1. Text layers fix both.
Correction: text layers fix B. For A, the 1978/1982 notices are scans, so that one needs OCR. Next I'll check which years have text layers.
Text layer check, 2 sampled PDFs per year: every PDF from 2002 on has one, every one before is a scan. So 2,355 notices (2002+) are readable now; the other 4,979 (1955–2001) need OCR. Want me to start parsing route bodies for 2002+?
Before parsing bodies, I'd change it to: one row per route mentioned in a notice (action, number, name, PDF page, quoted text). Then which mentions are "the same route" becomes a separate layer we can fix by hand. Sound right?

commit 50fbac7

Yes, sounds good. When you extract text from PDF, please put text in a file so we don't have to redo the text extraction every time we source text from PDF.