Methodology
How Location Astrology is calculated
Relocation advice is only worth as much as the arithmetic under it. This page says what that arithmetic is — where the planetary positions come from, how a distance to a line is measured, and exactly how a city's score is put together. Everything below describes code that runs; the last section says what we don't claim.
01 · Positions
Swiss Ephemeris, which is JPL DE431
Every planetary position on this platform comes from the Swiss Ephemeris, which is the Jet Propulsion Laboratory's DE431 ephemeris in compressed form — the same source professional astronomical software uses, accurate to a small fraction of an arcsecond over the range any birth chart needs. ΔT, the drift between atomic and rotational time, is applied inside it.
There is exactly one place in this codebase that asks the ephemeris for equatorial coordinates. The map lines, the Local Space rays and the relocated charts all read from it. A planet cannot move on one screen without moving on the others.
02 · The question Vedic astrologers ask first
Which ayanamsa do the lines use? None.
A planetary line marks where a planet is angular — on the horizon or the meridian — and that is a fact about the sky and the spinning Earth, not about where anyone has chosen to start the zodiac. The lines are computed in equatorial coordinates, right ascension and declination, so they carry no ayanamsa at all. Switching from Lahiri to Krishnamurti will not move your Jupiter MC line by a metre, and any tool whose lines do move is telling you something about its code rather than about the sky.
Two things on the same map are ayanamsa-dependent, and that is not an inconsistency. The sign bands — which rashi holds the Midheaven at each longitude — are boundaries of the zodiac, so they are definitionally wherever the ayanamsa puts them; ours are sidereal, converted for the coordinate change. And the relocated chart is a Vedic chart: sidereal, with Lahiri, Krishnamurti or Raman available.
03 · Geometry
Distance to the line, not to the dots it was drawn with
A line is drawn by sampling it, and the samples are about 111 km apart. It is tempting to measure a city's distance by finding the nearest sample — and wrong, because a city sitting exactly on a line but midway between two samples would read as tens of kilometres away from it.
We measure the cross-track great-circle distance to the arc between the samples, so the answer is the distance to the line itself and the sampling density sets no accuracy floor. When the panel says a Jupiter MC line passes 142 km north of you, 142 km is the distance to the line.
04 · Strength
Kilometres and degrees run through one curve
Two different kinds of nearness matter in this reading: how close a city is to a planetary line, in kilometres, and how close a planet is to an angle of the relocated chart, in degrees. Most systems score these from two separate hand-tuned tables, which then drift apart.
Ours are the same curve. Distance is divided by 111.195 km per degree and fed to the same smooth Gaussian that scores ecliptic angularity, so 334 km from a line and 3° from an angle carry equal weight by construction rather than by coincidence. Influence fades gradually; there is no step where a city abruptly stops counting.
05 · Scoring
Sixteen goals, and the formula is published
A place that suits a career does not automatically suit a marriage, so there is no single "good place" score. Sixteen life goals — career, business, wealth, marriage, romance, property, children, health, peace of mind, education, spiritual life, foreign settlement, travel, fame, politics and the arts — each carry their own weighted house formula and their own natural significators.
Those formulas are not written into the interface. The interface asks the engine for them, so what you are shown and what is computed cannot drift apart. Every city score comes back with its component parts, the weights that combined them, and a list of the factors that moved it — each tagged with the method that produced it.
06 · Vedic layers
Divisional charts and three dasha systems
Where a goal has a confirming divisional chart, it is used: D2 for wealth, D4 for property, D9 for relationships, D10 for career, D20 for spiritual life. A varga is gated when the birth time is not accurate enough to support it, and the response says when that happened rather than quietly scoring anyway.
Timing is read through Vimshottari, Char (Jaimini) and Yogini dashas, individually or averaged together. Each conclusion is tagged [V] [C] [Y] so you can see which system said what — and where they disagree, you can see that too.
07 · Settings
What you can change, and what it touches
- Lunar node
- Mean (default) or True. The true node is the instantaneous one and sits up to about 1.7° from the mean. Affects Rahu and Ketu everywhere they appear.
- House system
- Eight available, Placidus by default. Affects the relocated chart only — a map line is an angle, and every house system agrees about the angles.
- Topocentric
- Off by default. Corrects for the observer's position on Earth's surface; worth up to about a degree for the Moon and negligible otherwise.
Every setting defaults to what the platform has always done, so nothing moves under you unless you move it — and whichever settings produced a reading are returned with that reading, because a chart on the true node with Koch houses is a different chart and you should be able to see that it was.
08 · Honesty
What we don't claim
- Topocentric correction does not apply to the map lines. A line is computed for every point on Earth at once, so there is no observer for parallax to correct for. We offer it where there genuinely is one — the relocated chart and Local Space — and not where there is not.
- The four cardinal-angle lines stop at ±85° latitude. Beyond the polar circles a body can be circumpolar for half the year and the rising and setting lines stop being well defined. Quadrant house systems are undefined up there too; we substitute Equal houses and say so in the response rather than answering a different question quietly.
- City scores are drawn from a curated catalogue. Rankings and zone readings cover the cities in it, not every settlement on Earth. A region containing none of them returns no score and says so — it does not return zero, because zero is a score and absence is not.
- A zone score is an average, not a total. Drawing a bigger box does not earn a better number. The lines crossing a region are shown as evidence for the average, never as a contribution to it.
- Lifestyle data is kept out of the astrology. Cost of living, climate and connectivity belong beside a score, never inside it. Where we show them they are labelled separately.
- The AI never calculates. It receives finished engine output — scores, distances, lines, dashas — and writes it in plain language. Every sentence it produces is traceable to a number on this page.
- And the obvious one. Astrology is not a guarantee. A well-supported city is a place worth considering, weighed alongside visas, work, money and the people you would be leaving.
Read your own map.
Open Location AstrologyFrequently asked questions
Which ayanamsa do the astrocartography lines use?
None. Planetary lines are computed in equatorial coordinates — right ascension and declination — so they carry no ayanamsa and do not move when you switch between Lahiri, Krishnamurti or Raman. The sign bands and the relocated chart are sidereal, because a sign boundary is definitionally wherever the ayanamsa puts it.
How accurate are the planetary positions?
Every position comes from the Swiss Ephemeris, which is NASA JPL DE431 in compressed form, with the atomic-to-rotational time correction applied inside it. The same source feeds the map lines, the Local Space rays and every relocated chart.
How is the distance from a city to a planetary line measured?
By cross-track great-circle distance to the line itself, not to the points it was drawn with. Lines are sampled about 111 km apart, so measuring to the nearest sample would put a city sitting exactly on a line tens of kilometres away from it.
Is one location score used for every purpose?
No. Sixteen life goals — career, wealth, marriage, property, health, spiritual life and others — each have their own weighted house formula and significators, and the interface asks the engine for those formulas rather than keeping its own copy.
Does the AI work out the astrology?
No. The AI receives finished engine output — scores, distances, planetary lines, dashas — and writes it in plain language. Every sentence it produces traces back to a computed number.
Talk it through with an astrologer — your charts and reports are already on file, so there is nothing to re-enter.