> ## Documentation Index
> Fetch the complete documentation index at: https://docs.geometry.app/llms.txt
> Use this file to discover all available pages before exploring further.

# Data coverage

> One spine, thirty systems — 1900–2100.

# Data coverage

Every row keys to a single date dimension spanning **1900–2100** (73,414 days). On that spine:

| Layer               | What's on it                                                                                                  |
| ------------------- | ------------------------------------------------------------------------------------------------------------- |
| **Calendars**       | Gregorian, Chinese/Vietnamese lunar years, Hebrew, Persian (Nowruz), Vedic samvatsara, Mayan Long Count       |
| **Sky**             | Moon phases, seasons (solstice/equinox anchors), planetary retrogrades and sign ingresses                     |
| **Cards**           | Cardology birth cards, karma/planetary spreads, tarot, full compatibility connection system                   |
| **Numbers**         | Numerology systems, gematria ciphers, life-path math                                                          |
| **Signs & symbols** | Tropical + sidereal zodiacs (13-sign true sidereal included), Chinese zodiac, I Ching, runes, ogham, geomancy |

**How sky dates are calculated:** moon, season, and planetary event anchors are computed offline with the **standard Swiss Ephemeris** Python stack — the same widely used astronomical library many production astrology and astronomy systems rely on — then **stored and served as lookups**. There is no live ephemeris at request time on the published spine.

All of it: pre-computed, lowercase-normalized, served as structured JSON.

**Full payload:** these docs summarize coverage. For every field the tools return, [call a tool](/tools/overview) — the live JSON is the complete payload (no separate `full_payload` flag).