What the catalogue records

Every entry has a stable identifier, a category, a measurement in metres, a labelled dimension, a selection note and a source link. Our first collection contains 113 entries. Measurements are selected independently; no competitor catalogue or silhouette library is used.

Choosing a value

  • Animals: the note states a zoo’s adult reference or a published upper size. Values are not species-wide averages.
  • Dinosaurs: museum body-length estimates. Reconstructions carry uncertainty.
  • Landmarks: a specified height or length, explicitly including or excluding spires, antennas, pedestals or approaches.
  • Vehicles: a named model and dimension from a manufacturer or operator.
  • Planets and moons: the note distinguishes equatorial, rounded or table diameters. Rings and orbits are excluded.
  • Equipment: a regulated dimension, a chosen value in an allowed range or a labelled conversion from circumference.
  • Geography and nature: maximum published lengths, summit elevations, tree heights or waterfall drops, with their reference stated.

Defined everyday references

The 1.70-metre person is a deliberately chosen reference, not an average. The 80-inch door is another defined example. Neither requires a claim that all people or all doors share those dimensions.

How we draw the scale

Original SVG drawings are schematic illustrations. The bounding dimension along the labelled axis is assigned the recorded measurement. One metres-to-pixels scale then applies to both drawings. The camera fits the scene; it does not change a guess. Geography icons are not map outlines, and mountain icons are not surveyed profiles. Catalogue portrait thumbnails are explicitly not to scale.

Transparent scoring

Let the error factor be the larger of guess ÷ true size and true size ÷ guess. A factor up to 1.03 scores 100. Otherwise, score = 100 × (1 − log(error factor) ÷ log(4)), rounded and capped at 0–99. Negative results become zero. Thus half and double both score 50. Five rounds total 500.

Daily generation and fair challenges

A fixed catalogue version, the UTC date and the collection produce a deterministic daily set. Friend links include a seed and version, so recipients get the same comparisons. The first release uses version 1. Catalogues and game formulas should be versioned together if expanded later, to preserve old challenge links.

Personal stats, not invented rankings

Best scores, completed sets and daily streaks are stored locally. A global percentile would require real, consistently collected player results; none is displayed.

Corrections

Sources can change and better measurements can become available. If a selected value, convention or link is wrong, use the contact form and include the object name, proposed correction and source URL.