How the Lines Work

The four angles

Every chart has four angles, and The Birth Chart page introduces them in the wheel. On the map they become lines.

The Ascendant line is where a planet was rising at the moment you were born. The Ascendant is how you arrive, so on this line the planet sits in how you come across, in your body and presence, in how a place meets you.
The Descendant line is where the planet was setting. The Descendant is the doorway to other people, so this line is about who you draw to you in that place, partners and relationships, and what comes to you through others. You may feel much the same on a Descendant line, and it is the people around you who carry the planet.

The Midheaven line is where the planet was directly overhead. The Midheaven, MC for short, is the top of the chart and the cusp of the tenth house, so this line is career, public life, reputation and what you build in the world.

The IC line is where the planet was directly underfoot. IC stands for Imum Coeli, the bottom of the sky, and it is the cusp of the fourth house. This line is home, roots, family, the private life and the ground you stand on. It is the most private of the four, and in my experience the one people feel most and talk about least.

The Houses page covers the same four points as the cusps of houses one, seven, ten and four.

How the lines are found

Picture the Earth at the instant of your birth. The Sun is directly overhead somewhere, and at that moment it is overhead for every place on the same line of longitude from pole to pole. That is your Sun Midheaven line, and it is straight on the map. Go round to the far side of the globe, to the opposite line of longitude, and the Sun is directly underfoot. That is your Sun IC line, straight as well.

Rising and setting work differently. Where a planet sits on the horizon depends on how far north or south you are as well as how far east or west, so the Ascendant and Descendant lines curve across the map in long arcs.

Do that for each of the seven planets and you have twenty eight lines.

The seven planets

I work the map with the Sun, the Moon, Mercury, Venus, Mars, Jupiter and Saturn. Uranus, Neptune and Pluto have lines too, and many astrologers read them. I keep to the seven that move a life in ways you can feel, and when an outer planet's line runs hard through a place someone is asking about, I will mention it in the reading.

Distance from a line

A line's influence is strongest when you are within a few hundred kilometres of it and fades as you move away. Most astrologers treat something like 500 to 1,000 kilometres as the band worth reading, and I work the same way. I read the nearest lines to a place and say how close each one runs.

Where two lines cross, or run close together for a stretch, both planets speak at once, and the mix is the reading. A Venus line crossing a Saturn line is a very different place from either one on its own.

The birth time

Everything on this map hangs on the moment of birth. A birth chart with a rough time still has its Sun, its Moon and its aspects. An astrocartography map with a rough time has every line in the wrong place.

The Midheaven lines move about a degree of longitude for every four minutes of clock time. Fifteen minutes is nearly four degrees, which at the latitude of Perth is about 350 kilometres, enough to carry a line from the city to the far edge of the wheatbelt.

The time is read in the place where you were born and in the time zone that applied there on that day, with daylight saving checked for that year. A chart drawn with the wrong zone can be an hour out, and so is every line on the map. If you do not have your time to within about fifteen minutes, the map is a sketch, and I will tell you so.

Where it came from

Astrocartography is modern. The idea of relocating a chart, redrawing it for a new place, is old, but the map of lines was worked out and named by the American astrologer Jim Lewis in the 1970s, when computers first made it practical to draw. Before that nobody was going to calculate twenty eight curves by hand for one client. I use the lines the way I use the rest of the chart, as one tool among several.

How I read a relocation

You take your chart with you wherever you go. A place changes which parts of it are turned up loud, and that is all it changes. So I read the lines near a place against the whole birth chart, and the chart comes first.

A line is read with the planet's condition in the natal chart. A well placed Saturn's line is steadying, a place where work gets done and foundations get built. A Saturn that is hard pressed in the chart, squared and strained, has a line that asks more of you and gives back more slowly. The Planets page and the seven planet pages under it tell you how to judge a planet's condition, and I look there before I look at the map.

The lines that run close to your birthplace belong to the planets that were near the angles when you were born, and they are the ones your birth chart already shows as strong.

What a reading looks like

When someone brings me a place, I find the two or three nearest lines to it, say how close each one runs, and read them against the chart. Then I say what the place looks good for. A Saturn Midheaven line is a place to work and build a reputation, which suits some seasons of a life and would wear thin in others. A Jupiter line is a place where doors open, and where it is easy to walk through too many of them.

That is guidance. It says how a place is likely to meet you and leaves what you do there to you. Nobody leaves my table having been told where to live. Transits and Retrogrades matter too, because a move made under a hard transit lands differently from the same move in calmer weather.

Which place has always pulled at you, and have you ever looked at what runs through it?

If you would like your own chart read, my readings are here.