this post was submitted on 12 Feb 2025
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Acrobat 7’s maximum PDF size limit (381 km²) overlaid on Germany (lemmy.world)
submitted 2 weeks ago* (last edited 2 weeks ago) by FlyingSquid@lemmy.world to c/map_enthusiasts@sopuli.xyz
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[–] lord_ryvan@ttrpg.network 35 points 2 weeks ago (2 children)

Some questions...

  1. How is this measured in sq km, rather than something digital such as pixels?
  2. Why is it 381? How did they arrive at that number?
  3. Why is there any limit at all, if it's this big?
[–] dohpaz42@lemmy.world 48 points 2 weeks ago* (last edited 2 weeks ago) (1 children)

Beginning with PDF 1.6, the size of the default user space unit may be set with the UserUnit entry of the page dictionary. Acrobat 7.0 supports a maximum UserUnit value of 75,000, which gives a maximum page dimension of 15,000,000 inches (14,400 * 75,000 * 1 ⁄ 72). The minimum UserUnit value is 1.0 (the default).

15 million inches happens to be exactly 381 km Source

[–] gressen@lemm.ee 16 points 2 weeks ago (1 children)

That's sooooo arbitrary.

[–] Arigion@feddit.org 14 points 2 weeks ago

True. But thankfully most of the world uses centimetrs instead of inches nowadays. 😉

[–] Successful_Try543@feddit.org 30 points 2 weeks ago* (last edited 2 weeks ago) (1 children)

To satisfy the anything but metric postulate: 381 km originally are 15 million inches.

However, using some tricks, the size isn't limited to that.

https://alexwlchan.net/2024/big-pdf/

Remark: The side length of the square correspods to 381 km, subsequently, its area is 145161 km^2 .
381 km^2 are slightly smaller than the city of Cologne.

[–] ChaoticNeutralCzech@feddit.org 8 points 2 weeks ago (1 children)

Good to see Germany won't run out of PDF for their digital mapping efforts and need a costly replacement.

[–] Successful_Try543@feddit.org 1 points 2 weeks ago

I'm pretty sure, we would use a costly alternative anyways.