API Documentation
Atmospheris provides the ISO 2533 Standard Atmosphere model and ISO 5878 wind distribution calculations as both a Ruby gem and a TypeScript/JavaScript library. Both implement the complete set of atmospheric property calculations from the standard, covering all 19 derived properties across the full altitude range of −2,000 m to 80,000 m, plus Rice distribution wind modeling per ISO 5878.
Choose Your Language
TypeScript / JavaScript
Full TypeScript type definitions, tree-shakeable exports, and works with Node.js, browser bundlers (Vite, Webpack), and Deno.
npm install atmospherisRuby
The reference implementation — a comprehensive Ruby gem with object-oriented API, lazy computation, and full ISO coverage. Requires Ruby 3.0+.
gem install atmospherisProperty Groups
ISO 2533 organizes atmospheric properties into three groups, which both libraries return in a single result object:
Group 1 — Primary
- Geopotential & geometric altitude
- Temperature (K, °C, °F, °R) & temperature ratio
- Molecular temperature & lapse rate
- Pressure (Pa, mbar, mmHg) & pressure ratio
- Density & density ratio
Group 2 — Derived (Motion)
- Gravity & gravity ratio
- Speed of sound & speed ratio
- Dynamic viscosity (Sutherland’s formula)
- Kinematic viscosity
- Mean particle speed
Group 3 — Derived (Other)
- Specific weight
- Pressure scale height
- Thermal conductivity
- Air number density
- Collision frequency
- Mean free path & mole volume
Precision Modes
Both libraries support two precision levels, matching the presentation conventions in ISO 2533:
- Normal precision — Full significant figures for engineering calculations. Matches ISO 2533 Tables 5–7.
- Reduced precision — Fewer significant digits, matching the reduced-precision tables in ISO 2533 Tables 8–10.
Both modes use the same underlying formulas; only the output rounding differs. The precision setting does not affect calculation accuracy — only the number of digits presented in the result.