Observer latitude and longitude
The terrestrial coordinate contract behind ascendants, houses, rise and set times, and topocentric positions.
Calculation contract · released 2026-08-18
Definition
Observer coordinates locate the calculation origin on Earth. Longitude sets local rotation angle; latitude sets the horizon orientation.
Calculation procedure
Resolve a named place to WGS 84 coordinates, retain the selected result and uncertainty, validate axis order and sign, and never infer coordinates from timezone alone.
Required inputs
- Named place or coordinates
- Horizontal coordinate reference system
- Latitude/longitude uncertainty
- Location-selection evidence
Maha convention
Maha records latitude and longitude in decimal degrees under EPSG:4326 and keeps place lookup separate from chart computation.
Uncertainty and edge cases
Town-centroid coordinates are adequate for many reports but are not equivalent to a surveyed event site; angular sensitivity should be tested near boundaries.
What this does not establish
A geocoder result does not prove the person or event was physically at that point.
Authoritative references
These sources establish the calculation vocabulary, data product, or transformation convention. They do not establish astrological interpretation.
- WGS 84 geographic 2D coordinate reference system
EPSG Geodetic Parameter Registry · EPSG:4326 (revision 2022-11-29)
The WGS 84 latitude and longitude coordinate reference system and axis/unit definitions used for terrestrial observer locations.
Boundary: EPSG:4326 is horizontal; elevation must separately name its value, unit, reference, and uncertainty.