Lines on the world map where planets were angular at your birth.
At the moment you were born, each planet was on the horizon or the meridian of some point on Earth. Joining those points gives four lines per planet, and the technique consists of reading them: where a line runs, that planet is at its most prominent. Most places have no line nearby, and that is the normal condition.
What each angle tells you
A line takes its meaning from the angle the planet sits on. On the Midheaven it speaks of public role, career and how others see you. On the Imum Coeli it concerns home, roots and private life. On the Ascendant it touches how you come across and how you start things, the body included. On the Descendant the emphasis falls on relationships: partners, associates, other people in general.
The planet tells you what is involved, the angle tells you where it shows. Venus on the Midheaven and Venus on the Imum Coeli are the same Venus from your chart, but the first expresses itself in public life and the second at home. No line is purely favourable: traditionally even the most coveted carry a cost, and the most feared a gift.
How close a line needs to be
A line is not a thin thread: it is read as a band. There is no value everyone agrees on, but the most common treats a line as active within about 150 kilometres and weaker out to 300. Beyond that, the planet weighs exactly what it weighs in your birth chart, no more and no less.
On SideraMea there are forty-four lines, four for each of eleven bodies: the Sun, the Moon, the planets out to Pluto, and Chiron. The North Node is left out, because it is a calculated point rather than a body that rises and culminates. You can also type in a city and see which lines pass near it, how far away they are and what they mean in the tradition.
Frequently asked questions
Should I move to where my Venus line runs?
No line is an instruction about where to live. Astrocartography is a symbolic tool for thinking about how you might experience a place, not a map of the right destinations. Used sensibly, it is weighed against what you already know about yourself and your life: a place on a Venus line is read as pleasant, but traditionally also as one where focus can slip.
Do you need an exact birth time for astrocartography?
Yes, more than for many other techniques. The Earth turns roughly one degree every four minutes, and the lines turn with it: a four-minute error shifts the Midheaven and Imum Coeli lines by a degree of longitude, about 111 kilometres at the equator and less further north or south. With an unknown birth time, the whole map is unreliable.
Does astrocartography apply to a short trip?
Opinions differ. Many astrologers read it mainly for places where you live for a long time, where a line has time to make itself felt in everyday life. Others use it for travel and holidays too, as a way of understanding why a place stayed with you. Either way, it describes an atmosphere, not an event that is bound to happen.
See it in your own chart
Calculating your birth chart is free: wheel, planets, houses, aspects and a first reading. All you need is your date, time and place of birth.