Your birth chart is cast for one moment and one place. Change the place and keep the moment, and the planets stay exactly where they were in the zodiac, but the houses and angles move. That simple fact is the basis of two related techniques: relocation charts, which recalculate your chart for a new city, and astrocartography, which draws your whole chart across a world map at once.
People usually find these techniques when they're deciding whether to move, study abroad, or take a job in another country. They're useful for that, within limits. This guide explains what the lines on the map mean, how a relocation chart differs from your natal chart, how to use both sensibly, and where the method stops being reliable.
Where astrocartography comes from
The idea that a planet's strength depends on its position relative to the horizon and meridian is as old as horoscopic astrology. Angular planets (those near the Ascendant, Descendant, Midheaven, or IC) have always been considered the loudest in a chart.
What changed in the 1970s was the map. The American astrologer Jim Lewis developed a system for plotting, on a world map, every place where each planet in your birth chart was on one of the four angles at the moment you were born. He called it AstroCartoGraphy and trademarked the name. Computers made the calculation practical, and the technique spread quickly. Today most people say "astrocartography" for any map of this kind.
The four kinds of lines
At the moment you were born, every planet was rising somewhere on Earth, setting somewhere, culminating overhead somewhere, and at the lowest point below the horizon somewhere. An astrocartography map draws each of those as a line.
- MC line (Midheaven): the places where the planet was at the highest point of its daily arc, crossing the local meridian. Themes of career, reputation, and public role.
- IC line (Imum Coeli): the places where the planet was at the lowest point, directly below. Themes of home, family, roots, and private life.
- AC line (Ascendant): the places where the planet was rising on the eastern horizon. Themes of identity, body, and how you come across.
- DC line (Descendant): the places where the planet was setting on the western horizon. Themes of partners, close relationships, and the people you attract.
MC and IC lines run straight north-south, because a planet crosses the meridian at the same moment everywhere along one line of longitude. Each planet's MC and IC lines sit exactly 180 degrees of longitude apart. AC and DC lines curve, because the timing of rising and setting depends on latitude as well as longitude. The curves can bend sharply near the poles, which becomes important later.
What each planet's line tends to bring
The planet colors the place. Standard readings:
- QSun lines: visibility, confidence, being recognized. Sun on the MC is a classic career line.
- Moon lines: emotional comfort, domestic life, public mood. Moon on the IC often feels like home.
- Mercury lines: learning, writing, trade, busy social traffic.
- RVenus lines: pleasure, affection, art, easier social life. Venus on the DC is a well-known "relationship line."
- Mars lines: energy, competition, ambition, sometimes conflict or accidents.
- YJupiter lines: growth, opportunity, generosity from others, sometimes excess.
- USaturn lines: hard work, responsibility, structure, loneliness or delays. Often productive, rarely easy.
- Uranus, Neptune, Pluto lines: disruption and freedom, idealism and confusion, intensity and transformation, in that order.
Two refinements matter. First, the planet's condition in your natal chart carries over. A Venus in Scorpio squared by Saturn doesn't turn into pure delight because you live on its line; you meet that Venus more strongly, complications included. Second, a "difficult" line isn't automatically a place to avoid. Many people do their best work on a Saturn MC line.
Relocation charts: same moment, new place
A relocation chart is your birth chart recalculated for a different location but the same moment in universal time. The effect:
- Unchanged: every planet's sign and degree, every aspect between planets, retrograde status. You're still you.
- Changed: the Ascendant, Midheaven, all house cusps, and which house each planet falls in.
So relocation doesn't change your character. It changes where your character gets expressed. A natal chart with Venus in the 12th house might put Venus in the 10th when relocated, and the same affectionate, aesthetic nature becomes more publicly visible in that city.
The astrocartography map and the relocation chart describe the same thing from two angles. Standing on a planet's MC line is the same as having that planet exactly on the Midheaven of your relocated chart. The map shows you the whole world at a glance; the relocation chart shows the full house picture for one specific place.
A worked example
Say someone was born in London with 20 degrees Leo rising and the Sun at 5 degrees Taurus close to the Midheaven. In London, their Sun sits right on the career angle.
Now relocate the chart to New York. The Earth turns 15 degrees of longitude per hour, and New York is about 74 degrees west of London. At the moment of birth it was roughly five hours earlier on the clock in New York, so the local sky was earlier in its daily turn. A planet that was culminating over London was still climbing in the east over New York.
In the New York relocation chart, the Midheaven moves back by roughly 74 degrees of right ascension, and the Sun, still at 5 Taurus, is no longer near the top of the chart. It lands in the 12th house, not far above the Ascendant. The person is the same, with the same Taurus Sun and the same aspects, but in New York that Sun works more privately, behind the scenes, or through retreat and inner work rather than public status. Their London Sun MC line, meanwhile, runs north-south through London and would pass through other cities on the same meridian.
If they were weighing London against New York for a career move, the map would already have told them which city put the Sun on the MC.
How to use a map sensibly
A few working habits make astrocartography far more useful:
- Look at distance, not just the line. Influence is strongest close to the line and fades with distance. Practitioners disagree on exact limits, but most treat the nearest few hundred miles as the strong zone.
- Start from the natal chart. Check which planets are strong or troubled at birth before deciding which lines to seek or avoid. A well-placed Jupiter is worth moving toward. A badly afflicted one may deliver its problems on a larger scale.
- Match the line to the purpose. An MC line suits career moves. An IC line suits settling down. A DC line suits meeting partners. The same line can be great for one goal and irrelevant to another.
- Read the relocated houses too. Even far from any line, a relocation chart can move important planets into more helpful houses.
- Watch transits to the relocated angles. When a transit crosses a relocated angle, the city tends to "switch on" that theme for a while. See transits explained for the timing side.
Limits and common mistakes
- Birth time precision matters a lot. The Earth rotates one degree every four minutes. A birth time off by 8 minutes shifts every MC and IC line by about 2 degrees of longitude, which is more than 200 kilometres at the equator. If your time is rounded, treat lines as broad bands. Birth time explains why this matters in any chart.
- High latitudes distort. Near the Arctic and Antarctic circles, AC and DC lines curve wildly and some house systems stop working properly, since certain degrees never rise at all.
- Lines aren't guarantees. A Venus line won't hand you a partner. It describes a theme that's more available, not an event.
- Don't cherry-pick. Almost every major city lies near some line. It's easy to justify any move you already wanted to make.
- Short visits aren't the same as living there. Most practitioners find relocation effects clearest when you actually live somewhere, not during a weekend trip.
- You take your natal chart with you. Relocation reshuffles emphasis. The underlying aspects and challenges travel along.
Start with your natal angles
Before looking at any map, you need to know your natal angles and which planets are near them, because astrocartography is built on exactly that. Cast your chart with an accurate birth time, note the Ascendant and Midheaven degrees, and see which planets sit closest to them.
If you're unsure how the angles and houses work, the twelve houses explained is the best place to start, and rising sign explained covers the Ascendant in detail.