Height or length: the axis problem
A blue whale is 27 m long. The Eiffel Tower is 330 m tall. Those two sentences use the same grammar and describe completely different measurements, and almost every bad size comparison you have ever read starts by pretending they do not.
The split, in numbers
Of the 393 measured objects behind this game, 210 carry a height and 183 carry a length. That is very nearly an even split, which means that any two objects picked at random have close to a one-in-two chance of being measured on different axes. If you compare their figures without noticing, you have not compared their sizes. You have compared two unrelated distances that happen to be expressed in the same unit.
The rule the game uses is simple and it is stated on every object: one real-world size, one axis it belongs to. An upright thing is judged by height. A long thing is judged by length. Nothing carries both, because carrying both would let a round be scored two different ways.
What a mismatch looks like
Take the Eiffel Tower against Titanic. The tower is 330 m tall. Titanic was 269.1 m long. The ratio is 1.23, and it is a perfectly reasonable thing to say out loud: the tower is taller than the ship is long. What you cannot do is conclude anything about how the two would look parked next to each other, because one of them is lying down.
Stood on its end, Titanic would reach four fifths of the way up the tower, which is a real and vivid fact. Floating, it occupies a rectangle of water 269 m by 28 m and reaches about 53 m above the waterline, and the tower would dwarf it completely. Both statements come from the same two numbers. The difference is entirely in the axis.
The clearest case in the catalogue: the Andean condor at 3.2 m and the American bison at 1.75 m. The condor's figure is a wingspan, taken tip to tip with the wings open. The bison's is shoulder height on a standing animal. The ratio is 1.83, and a condor standing on a bison's back would not reach its own stated size in any direction.
Why not just give both numbers?
Because for most objects the second number is either meaningless or unstable. A giraffe has a height that matters and a nose-to-tail length that almost nobody has ever quoted. A blue whale has a length that matters and a height that depends entirely on which way up you catch it. Publishing two figures where only one is conventional would look more rigorous and be less so.
There is also a practical reason. A comparison with two numbers on each side has four possible pairings, and three of them are wrong. Fixing one axis per object means the comparison has exactly one reading, and the reader does not have to guess which one was intended.
How the axis gets chosen
For most objects the choice is obvious, and it follows what people already say. Nobody asks how tall a whale is. Nobody asks how long a tower is. The convention already exists in ordinary speech and the catalogue just records it.
Where it is not obvious, three rules settle it:
- Follow the published convention. Ships are quoted length overall, so Icon of the Seas is 364.75 m long, not tall, even though it is a very tall object. That is the figure harbours use and the figure every source gives.
- Follow the pose. A saltwater crocodile is 4.5 m long because a crocodile is a horizontal animal. A grizzly bear is 2.5 m tall because the figure that gets published is the upright one. Both are measured in the posture the animal is normally described in.
- Follow the largest meaningful dimension. For a country there is no natural axis, so the outline is judged on whichever span is the more informative. Texas gets an east-west figure of 1,244.8 km. Italy gets a north-south figure of 1,288.9 km. Each matches the shape.
The axis decides the drawing, too
This is the part that is easy to get wrong in a picture. If you scale two silhouettes by fitting them to a box, a long low shape and a tall narrow shape both fill the frame and the comparison is destroyed. Scaling has to be done on the measured axis: a whale sized by its length, a tower sized by its height, and then whatever the other dimension comes out as is simply what it is.
That is why some of the drawings on this site look lopsided. Hubble at 13.2 m against a Stegosaurus at 7 m puts a long thin cylinder beside a chunky animal, and the cylinder dominates the frame without dominating the numbers. A drawing that corrected for that would be prettier and would be lying.
Reading a mixed-axis comparison properly
When the two axes differ, the honest reading is narrow and it is worth stating explicitly: this many metres of that thing, measured that way, against this many metres of the other, measured this way. The ratio is still arithmetic and still correct. What it does not support is a claim about how the two would look together.
Godzilla at 119.8 m against the International Space Station at 109 m is a good example. The station's figure is across its solar arrays, the widest part, and the pressurised modules people actually live in run about seventy metres. So the comparison is a standing height against a panel span, the ratio is 1.10, and anything beyond that is invention.
Once you are in the habit of asking which axis, most published size comparisons start looking shakier and the good ones start looking much better. It is the cheapest single improvement available to anyone writing about size.