Ha, nice! I secretly hoped someone would mention their real-world usage of "ridiculously" large SVG dimensions, so thanks for the reference!

Your story implies there actually were some viewers that could handle it correctly? Could you recall more details what were they? (My testing was pitifully limited to current browsers only, but I know there must be vast amount of other viewers.)

And if I may ask, did you map one SVG "point" to some length unit (e.g. meter, so getting 84e6 wide wiewBox), or did you assume 90 DPI "pixel" mapping to ~0.2822 mm?

I've just re-tested, and you're right. This SVG won't display properly with chrome, firefox, inkscape or imagemagick

  <?xml version="1.0" encoding="UTF-8" standalone="no"?>
  <svg width="84000000000mm" height="84000000000mm"
     viewBox="0 0 84000000000mm 84000000000mm"
     version="1.1" id="svg5"
     xmlns="http://www.w3.org/2000/svg"
     xmlns:svg="http://www.w3.org/2000/svg">
    <ellipse
       style="fill:none;stroke:#000000;stroke-width:0.812697;stroke-opacity:1"
       id="path111" cx="42000000000mm" cy="42000000000mm"
       rx="42000000000mm" ry="42000000000mm" />
  </svg>

However the browsers don't crash or run out of memory, so they've got that going for them. And if you embed the image in a web page with <img src='84km.svg' width=1000 height=1000> chromium almost manages to display it.

SVG lets you specify sizes in a bunch of different units, but there's actually a fixed ratio between them - in SVG, 1mm means is 3.78px regardless of your display or printer's DPI.

So I didn't scale mm to SVG's arbitrary length units - but the standard did.

So at this point we don't know about any viewer capable of handling Earths orbit sized SVG? That's sad.

> However the browsers don't crash or run out of memory

Good news for your sample. Yet in some browsers there prevail some open issues, just the limits are now farther. For example feeding this SVG to my Firefox almost instantly exhausts my RAM and makes the browser window unusable for a while:

    data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg"
     viewBox="-1e11,-1e11,2e11,2e11"><circle r="1e11"/></svg>

I guess for more beefed machines would be necessary to bump exponents slightly higher. It's a known issue [1].

[1] https://bugzilla.mozilla.org/show_bug.cgi?id=1864374

From looking at the following pages

- https://docs.aspose.com/svg/net/drawing-basics/coordinate-sy...

- https://www.w3.org/TR/SVG2/coords.html

- https://developer.mozilla.org/en-US/docs/Web/SVG/Tutorial/Po...

You can use “cm” and “mm” in SVG.

It will then be up to the viewer program (web browser or which ever program you are using) to make it correct for the DPI of your display.

I tried to make a daily timeline in SVG where 1 unit = 1 second. There are 86400 seconds in a day. Both Firefox and Chrome did not render the image properly, so I had to scale the numbers down too. What a shame.